Venlafaxine (
Effexor,
Efexor) is an arylalkanolamine
SNRISerotonin-norepinephrine reuptake inhibitors are a class of antidepressant drugs used in the treatment of major depression and other mood disorders...
, although some authors dispute the claim that it inhibits
NENoradrenaline or norepinephrine is a catecholamine with dual roles as a hormone and a neurotransmitter....
reuptake. First introduced by
WyethWyeth, formerly known as American Home Products , was one of the largest pharmaceutical companies in the world. The company is based in Madison, New Jersey...
in 1993, it is licensed for the
ameliorationAmelioration may refer to one of the following.*Amelioration means "to make better" or "to improve upon" most often in context of or in reference to ill health of a person but could also be in reference to healing the land, plant, tree, etc....
(
cf.cf. is an abbreviation for the Latin word confer, meaning "compare" or "consult", and is hence used to refer to other material or ideas which may provide different information or arguments...
palliation) of MDD, as an
anxiolyticAn anxiolytic is a drug used for the treatment of symptoms of anxiety. Anxiolytics have been shown to be useful in the treatment of anxiety disorders, as have antidepressants such as the selective serotonin reuptake inhibitors .Though not anxiolytics, beta-receptor blockers such as propranolol and...
, & comorbid
indicationsIn medicine, an indication is a term describing a valid reason to use a certain test, medication, procedure, or surgery. In the United States, indications for medications are strictly regulated by the Food and Drug Administration, which includes them in the package insert under the phrase...
. In 2007, venlafaxine was the sixth most commonly prescribed antidepressant on the U.S. retail market, with 17.2 million prescriptions. In children and adolescents, venlafaxine has a potential to increase suicidal thoughts, attempts and events of self-harm.
Approved
Venlafaxine is used primarily for the treatment of major depression, generalized anxiety disorder,
social anxiety disorderSocial anxiety disorder , also known as social anxiety or social phobia is a diagnosis within psychiatry and other mental health professions referring to excessive social anxiety causing considerable distress and impaired ability to function in at least some areas of daily life...
, OCD,hot flashes in Menopause and
panic disorderPanic disorder is an anxiety disorder characterized by recurring severe panic attacks. It may also include significant behavioral change lasting at least a month and of ongoing worry about the implications or concern about having other attacks. The latter are called anticipatory attacks...
in adults.
Depression
Multiple double blind studies show venlafaxine's effectiveness in treating depression. Venlafaxine has similar efficacy to the tricyclic antidepressants
amitriptylineAmitriptyline is a psychoactive drug and pharmaceutical of the tricyclic antidepressant chemical class which is used primarily as an antidepressant and anxiolytic agent. It is the most widely prescribed TCA and perhaps also the most efficient against depressive symptoms.- Approved :Amitriptyline...
(Elavil) and
imipramineImipramine is an antidepressant medication, a tricyclic antidepressant of the dibenzazepine group...
, and is better tolerated than amitriptyline. Its efficacy is similar to or better than
sertralineSertraline hydrochloride is an antidepressant of the selective serotonin reuptake inhibitor class. It was introduced to the market by Pfizer in 1991. Sertraline is primarily used to treat major depression in adult outpatients as well as obsessive–compulsive, panic, and social anxiety disorders in...
(Zoloft) and
fluoxetineFluoxetine is an antidepressant of the selective serotonin reuptake inhibitor class. Fluoxetine is approved for the treatment of major depression , obsessive-compulsive disorder , bulimia nervosa, anorexia nervosa, panic disorder and premenstrual dysphoric disorder...
(Prozac), depending on the criteria and rating scales used. Higher doses of venlafaxine are more effective, and more patients achieved
remissionRemission may refer to:*Remission , the reflection or scattering of light by a material*Remission *Remission *Re-Mission, a video game for young people with cancer...
or were "very much improved". The efficacy was similar if the number of patients who achieved "response" or were "improved" was considered. A
meta-analysisIn statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. This is normally done by identification of a common measure of effect size, which is modelled using a form of meta-regression...
comparing venlafaxine and combined groups of SSRI or tricyclic antidepressants showed venlafaxine's superiority. Judged by the same criteria, venlafaxine was similar in efficacy to the atypical antidepressant
bupropionBupropion is an atypical antidepressant that acts as a norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist...
(Wellbutrin); however, the remission rate was significantly lower for venlafaxine. In a double-blind study, patients who did not respond to an SSRI were switched to venlafaxine or
citalopramCitalopram is an antidepressant drug used to treat major depression associated with mood disorders. It is also used on occasion in the treatment of body dysmorphic disorder and anxiety....
. Similar improvement was observed in both groups.
Consumer ReportsConsumer Reports is an American magazine published monthly by Consumers Union. It publishes reviews and comparisons of consumer products and services based on reporting and results from its in-house testing laboratory. It also publishes cleaning and general buying guides...
, which in 2004 had rated venlafaxine as the most effective among six commonly prescribed antidepressants, no longer recommends it.
FluoxetineFluoxetine is an antidepressant of the selective serotonin reuptake inhibitor class. Fluoxetine is approved for the treatment of major depression , obsessive-compulsive disorder , bulimia nervosa, anorexia nervosa, panic disorder and premenstrual dysphoric disorder...
,
citalopramCitalopram is an antidepressant drug used to treat major depression associated with mood disorders. It is also used on occasion in the treatment of body dysmorphic disorder and anxiety....
, and
bupropionBupropion is an atypical antidepressant that acts as a norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist...
have been chosen as Consumer Reports Best Buy drugs in the updated version of their guide, based upon effectiveness, safety, side effects, and cost.
Off-label / investigational uses
Many doctors are starting to prescribe venlafaxine "off label" for the treatment of
diabetic neuropathyDiabetic neuropathies are neuropathic disorders that are associated with diabetes mellitus. These conditions are thought to result from diabetic microvascular injury involving small blood vessels that supply nerves...
(in a similar manner to
duloxetineDuloxetine is a serotonin-norepinephrine reuptake inhibitor manufactured and marketed by Eli Lilly. It is effective for major depressive disorder and it is as effective as venlafaxine in generalised anxiety disorder. It is a well tolerated and is considered a first line treatment strategy...
) and
migraineMigraine is a neurological syndrome characterized by altered bodily perceptions, severe headaches, and nausea. Physiologically, the migraine headache is a neurological condition more common to women than to men. The word migraine was borrowed from Old French migraigne...
prophylaxis (in some people, however, venlafaxine can exacerbate or cause migraines). Studies have shown venlafaxine's effectiveness for these conditions.
It has also been found to reduce the severity of 'hot-flashes' in
menopausalMenopause is the time in a woman’s life when menstruation ends. It is part of a biological process that begins, for most women, in their mid-fifties. During this time, the ovaries gradually produce lower levels of natural sex hormones—estrogen and progesterone...
women.
Substantial weight loss in patients with major depression, generalized anxiety disorder, and social phobia has been noted, but the manufacturer does not recommend use as an
anorecticAn anorectic or anorexic , also known as anorexigenic or appetite suppressant, is a dietary supplements and/or drug which reduces appetite, food consumption, and as a result, causes weight loss to occur.-List of Anorectics:Numerous pharmaceutical compounds are marketed as appetite suppressants.The...
either alone or in combination with phentermine or other amphetamine-like drugs. Venlafaxine hydrochloride is in the phenethylamine class of modern chemicals, which includes amphetamine, methylendioxymethamphetamine (MDMA), and methamphetamine. This chemical structure likely lends to its activating properties; however, some patients find venlafaxine highly sedating despite its more common stimulatory effects.
Venlafaxine is not approved for the treatment of depressive phases of
bipolar disorderBipolar disorder, also known as manic depressive disorder, manic depression or bipolar affective disorder, is a serious mental disorder that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated mood clinically referred to as mania or, if...
; this has some potential danger as venlafaxine can induce
maniaMania is a severe medical condition characterized by extremely elevated mood, energy, unusual thought patterns and sometimes psychosis...
, mixed states, rapid cycling and/or
psychosisPsychosis literally means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
in some bipolar patients, particularly if they are not also being treated with a
mood stabilizerA mood stabilizer is a psychiatric medication used to treat mood disorders characterized by intense and sustained mood shifts, which is not the same as "feeling good one minute and then bad the next."-Uses:...
.
Due to its action on both the serotoninergic and
adrenergicAn adrenergic is a drug, or other substance, which has effects similar to, or the same as, epinephrine . Thus, it is a kind of sympathomimetic agent...
systems, venlafaxine is also used as a treatment to reduce episodes of
cataplexyCataplexy is sudden and transient episode of loss of muscle tone, often triggered by emotions. It is a rare disease , but frequently affects people who have narcolepsy, a disorder whose principal signs are EDS , sleep attacks, sleep paralysis, hypnagogic hallucinations and disturbed night-time sleep...
, a form of muscle weakness, in patients with the
sleep disorderA sleep disorder is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning...
narcolepsyNarcolepsy is chronic sleep disorder, or dyssomnia. The condition is characterized by excessive daytime sleepiness in which a person experiences extreme fatigue and possibly falls asleep at inappropriate times, such as while at work or at school...
.
Venlafaxine was found in one study to be equal to Anafranil in the treatment of OCD with fewer side effects.
Due to its tendency to increase blood pressure and its modulative effects on the
autonomic nervous systemThe autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...
, venlafaxine is often used to treat
orthostatic intoleranceOrthostatic intolerance is a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up....
and
postural orthostatic tachycardia syndromePostural orthostatic tachycardia syndrome is a condition of dysautonomia, and more specifically, orthostatic intolerance, in which a change from the supine position to an upright position causes an abnormally large increase in heart rate, called tachycardia...
.
Contraindications
Venlafaxine is contraindicated in children and adolescents because it can increase suicidal thoughts, attempts, and self-harm (see Venlafaxine#Suicidality). Furthermore, studies of venlafaxine in these age groups have not established its efficacy or safety. Venlafaxine is not recommended in patients
hypersensitiveHypersensitivity refers to undesirable reactions produced by the normal immune system. Hypersensitivity reactions require a pre-sensitized state of the host. The four-group classification was expounded by P. H. G...
to venlafaxine. It should not be taken by anyone who is allergic to the inactive ingredients, which include
gelatinGelatin is a translucent, colorless, odorless, brittle, nearly tasteless solid substance, derived from the collagen inside animals' skin and bones. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing. Substances containing gelatin or functioning...
,
celluloseCellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
, ethylcellulose,
iron oxideIron oxides are chemical compounds composed of iron and oxygen. Altogether, there are sixteen known iron oxides and oxyhydroxides.-Oxides:* FeO, iron oxide, * Fe3O4, iron oxide,...
,
titanium dioxideTitanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO
2. When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891...
and
hypromelloseHypromellose , short for hydroxypropyl methylcellulose , is a semisynthetic, inert, viscoelastic polymer used as an ophthalmic lubricant, as well as an excipient and controlled-delivery component in oral medicaments, found in a variety of commercial products.As a food additive, hypromellose is an...
. It should never be used with a
monoamine oxidase inhibitorMonoamine oxidase inhibitors are a class of powerful antidepressant drugs prescribed for the treatment of depression. They are particularly effective in treating atypical depression, and have also shown efficacy in smoking cessation....
(MAOI), as it can cause potentially deadly
serotonin syndromeSerotonin syndrome is a potentially life-threatening adverse drug reaction that may occur following therapeutic drug use, inadvertent interactions between drugs, overdose of particular drugs, or the recreational use of certain drugs...
. At least 14 days must pass between the use of venlafaxine and MAO inhibitors. Caution should also be used in those with a seizure disorder.
Glaucoma
Venlafaxine can increase eye pressure, so those with
glaucomaGlaucoma is a group of diseases that affect the optic nerve and involves a loss of retinal ganglion cells in a characteristic pattern. It is a type of optic neuropathy. Raised intraocular pressure is a significant risk factor for developing glaucoma...
may require more frequent eye checks.
Pregnant women
There are no adequate, well-controlled studies of venlafaxine in pregnant women. Therefore, venlafaxine should only be used during pregnancy if clearly needed. Prospective studies have not shown any statistically significant congenital malformations. There have, however, been some reports of self-limiting effects on newborn infants. As with other serotonin reuptake inhibitors, these effects are generally short-lived, lasting only 3 to 5 days, and rarely resulting in severe complications. Use of Venlafaxine in pregnancy should be considered on a case-by-case basis.
Heart disease and hypertension
The FDA asked the manufacturers of all SNRIs to include the risk of persistent
pulmonary hypertensionIn medicine, pulmonary hypertension is an increase in blood pressure in the pulmonary artery, pulmonary vein, or pulmonary capillaries, together known as the lung vasculature, leading to shortness of breath, dizziness, fainting, and other symptoms, all of which are exacerbated by exertion...
(PPHN) in prescribing data as of July 19, 2006. Medications containing venlafaxine caused a mean heart rate increase of 4 bpm in clinical trials, along with a sustained increase in blood pressure in some.
Suicide
The US Food and Drug Administration body (FDA) requires all antidepressants, including venlafaxine, to carry a black box with a generic warning about a possible suicide risk. In addition, the most recent research indicated that patients taking venlafaxine are at increased risk of suicide.
A study conducted in Finland followed more than 15,000 patients for 3.4 years. Venlafaxine increased suicide risk 1.6-fold (statistically significant), as compared to no treatment. At the same time,
fluoxetineFluoxetine is an antidepressant of the selective serotonin reuptake inhibitor class. Fluoxetine is approved for the treatment of major depression , obsessive-compulsive disorder , bulimia nervosa, anorexia nervosa, panic disorder and premenstrual dysphoric disorder...
(Prozac) halved the suicide risk.
In another study, the data on more than 200,000 cases was obtained from the UK general practice research database. The patients taking venlafaxine had significantly higher risk of completed suicide than the ones on
fluoxetineFluoxetine is an antidepressant of the selective serotonin reuptake inhibitor class. Fluoxetine is approved for the treatment of major depression , obsessive-compulsive disorder , bulimia nervosa, anorexia nervosa, panic disorder and premenstrual dysphoric disorder...
(Prozac) (2.8 times) or
citalopramCitalopram is an antidepressant drug used to treat major depression associated with mood disorders. It is also used on occasion in the treatment of body dysmorphic disorder and anxiety....
(Celexa) (2.4 times). Even after taking into consideration the fact that venlafaxine was generally prescribed for more severe depression, venlafaxine was associated with 1.6-1.7 times more suicides than fluoxetine or citalopram. This difference was no longer statistically significant due to the rarity of completed suicides. However, for the attempted suicides (more frequent event) the 1.2-1.3 times higher risk for venlafaxine still stayed statistically significant after the adjustment.
An analysis of clinical trials by the FDA statisticians showed the incidence of suicidal behaviour among the adults on venlafaxine to be not significantly different from fluoxetine or
placeboA placebo is a sham medical intervention. In one common placebo procedure, a patient is given an inert sugar pill, told that it may improve his/her condition, but not told that it is in fact inert...
. A possible explanation for this discrepancy is that suicidal patients are generally excluded from clinical trials, and so clinical trials do not represent the real population of patients.
Venlafaxine is contraindicated in children, adolescents and young adults. According to the FDA analysis of clinical trials venlafaxine caused a statistically significant 5-fold increase in suicidal ideation and behavior in persons younger than 25. In another analysis, venlafaxine was no better than placebo among children (7–11 years old) but improved depression in adolescents (12–17 years old). However, in both groups, hostility and suicidal behavior increased in comparison to those receiving a placebo. In a study involving antidepressants that had failed to produce results in depressed teenagers, teens whose SSRI treatment had failed who were randomly switched to either another SSRI or to venlafaxine showed an increased rate of suicide on venlafaxine. Among teenagers who were suicidal at the beginning of the study, the rate of suicidal attempts and self-harm was significantly higher, by about 60%, after the switch to venlafaxine than after the switch to an SSRI.
Common side effects
NOTE: The percentage of occurrences for each side effect listed comes from clinical trial data provided by Wyeth Pharmaceuticals Inc. The percentages indicate the percentage of people that experienced the side effect in clinical trials.
- Headache
In medicine a headache or cephalalgia is a symptom of a number of different conditions of the head. Some of the causes are benign while others are medical emergencies.There are a number of different classification systems for headaches...
(34%)
- Nausea
Nausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
(21-35%)
- Insomnia
Insomnia is a symptom of any of several sleep disorders, characterized by persistent difficulty falling asleep or staying asleep despite the opportunity. Insomnia is a symptom, not a stand-alone diagnosis or a disease. By definition, insomnia is "difficulty initiating or maintaining sleep, or both"...
(15-23%)
- Sexual dysfunction
Sexual dysfunction or sexual malfunction refers to a difficulty experienced by an individual or a couple during any stage of a normal sexual activity, including desire, arousal or orgasm.-Categories:...
(14-34%)
- Dry mouth (12-16%)
- Dizziness
Dizziness refers to an impairment in spatial perception and stability. It is considered imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or for a non-specific feeling such as giddiness or foolishness....
(11-20%)
- Sweating
Perspiration is the production of a fluid, consisting primarily of water as well as various dissolved solids , that is excreted by the sweat glands in the skin of mammals...
(10-14%)
- Decreased Appetite (8-20%)
- Abnormal ejaculation (8-16%)
- Hypertension
Hypertension is a chronic medical condition in which the blood pressure is elevated. It is also referred to as high blood pressure or shortened to HT, HTN or HPN. The word "hypertension", by itself, normally refers to systemic, arterial hypertension.Hypertension can be classified as either...
(4-5%)
- Vivid/Abnormal dream
Dreams are a succession of images, thoughts, or emotions passing through the mind during sleep. The content and purpose of dreams are not fully understood, though they have been a topic of speculation and interest throughout recorded history. The scientific study of dreams is known as...
s (3-7%)
- Akathisia
Akathisia, or acathisia, is a syndrome characterized by unpleasant sensations of "inner" restlessness that manifests itself with an inability to sit still or remain motionless...
(Agitation) (3-4%)
- Decreased libido (3-9%)
- Increased yawning (3-5%)
- Apathy
Image:Challenge_vs_skill.jpg|250px|Apathy in terms of challenge level and skill level. Clickable.|thumbpoly 66 7 211 9 285 189 254 234 67 152 Anxietypoly 221 7 428 7 351 188 296 187 294 188 Arousalpoly 439 7 583 7 584 149 388 236 360 194 Flow...
- Constipation
Constipation, costiveness, or irregularity is a condition of the digestive system in which a person experiences hard feces that are difficult to expel. This usually happens because the colon absorbs too much water from the food...
- Ongoing Irritable Bowel Syndrome
Irritable bowel syndrome is a functional gastrointestinal disorder. Also called spastic colon, it is a functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any detectable organic cause. In some cases, the symptoms...
- Fatigue
Fatigue is a state of awareness. It can describe a range of afflictions, varying from a general state of lethargy to a specific work-induced burning sensation within one's muscles. It can be both physical and mental...
- Vertigo
Vertigo is a specific type of dizziness, a major symptom of a balance disorder. It is the sensation of spinning or swaying while the body is actually stationary with respect to the surroundings.The effects of vertigo may be slight...
- Orthostatic hypotension
Orthostatic hypotension is a form of hypotension in which a person's blood pressure suddenly falls when the person stands up...
(postural drop in blood pressure)
- Impulsive Actions
- Electric shock-like sensations also called "Brain zaps"
- Increased anxiety at the start of treatment
- Memory Loss
- Restless Legs Syndrome
Restless legs syndrome , also known as Wittmaack-Ekbom's syndrome, is a condition that is characterized by an irresistible urge to move one's body to stop uncomfortable or odd sensations. It most commonly affects the legs, but can also affect the arms or torso and even phantom limbs. Moving the...
Less common to rare side-effects
Note 'Rare' adverse effects occur in fewer than 1 in 1000 patients.
- Cardiac arrhythmia
Cardiac arrhythmia is a term for any of a large and heterogeneous group of conditions in which there is abnormal electrical activity in the heart. The heart beat may be too fast or too slow, and may be regular or irregular....
- Increased serum cholesterol
- Gas or stomach pain
- Abnormal vision
- Nervousness, agitation or increased anxiety
Akathisia, or acathisia, is a syndrome characterized by unpleasant sensations of "inner" restlessness that manifests itself with an inability to sit still or remain motionless...
- Panic Attack
Panic attacks are very sudden, discrete periods of intense anxiety, mounting physiological arousal, fear, stomach problems and discomfort that are associated with a variety of somatic and cognitive symptoms. The onset of these episodes is typically abrupt, and may have no obvious triggers...
s
- Depressed feelings
- Suicidal thoughts
Suicidal Ideation is a common medical term for thoughts about suicide, which may be as detailed as a formulated plan, without the suicidal act itself. Although most people who undergo suicidal ideation do not commit suicide, some go on to make suicide attempts...
- Confusion
- Neuroleptic malignant syndrome
Neuroleptic malignant syndrome is a neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs. It generally presents with muscle rigidity, fever, autonomic instability and cognitive changes such as delirium, and is associated with elevated creatine...
- Loss of appetite
- Tremor
A tremor is an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, head, face, vocal cords, trunk, and legs. Most tremors occur in the hands. In some people,...
- Drowsiness
- Allergic skin reactions
- External bleeding
- Serious bone marrow
Bone marrow is the flexible tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells. It constitutes 4% of total body weight, i.e...
damage (thrombocytopeniaThrombocytopenia is the presence of relatively few platelets in blood.Generally speaking, in humans, a normal platelet count ranges from 150,000 and 450,000 per mm3. These limits, however, are determined by the 2.5th lower and upper percentile, and a deviation does not necessarily imply...
, agranulocytosisAgranulocytosis, also known as agranulosis, is an acute condition involving a severe and dangerous leukopenia, most commonly of neutrophils, causing a neutropenia in the circulating blood. It represents a severe lack of one major class of infection-fighting white blood cells...
)
- Hepatitis
Hepatitis implies injury to the liver characterized by the presence of inflammatory cells in the tissue of the organ. The name is from ancient Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
- Pancreatitis
Pancreatitis is inflammation of the pancreas that can occur in two very different forms. Acute pancreatitis is sudden while chronic pancreatitis "is characterized by recurring or persistent abdominal pain with or without steatorrhea or diabetes mellitus."...
- Seizure
An epileptic seizure is a transient symptom of excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms...
- Tardive dyskinesia
Tardive dyskinesia is a variety of dyskinesia manifesting as a side effect of long-term or high-dose use of dopamine antagonists, usually antipsychotics. Other dopamine antagonists that can cause tardive dyskinesia are drugs for gastrointestinal disorders and neurological disorders...
- Difficulty swallowing
- Psychosis
- Hair Loss
- Hostility
- Activation of mania/hypomania.
- Weight Loss (of concern when treating patients suffering from anorexia nervosa
Anorexia nervosa is a psychiatric illness that describes an eating disorder characterized by extremely low body weight and body image distortion with an obsessive fear of gaining weight...
)
- Weight gain (effect not clear, but of concern when treating people who may have Body Dysmorphic Disorder
Body dysmorphic disorder...
).
- Homicidal thoughts
- Aggression
- Depersonalization
Depersonalization is a malfunction or anomaly of the mechanism by which an individual has self awareness. It is a feeling of watching oneself act, while having no control over a situation...
- Visual Hallucinations
- Swollen and/or bleeding gums
- Frequent urination
Dose dependency of adverse events
A comparison of adverse event rates in a fixed-dose study comparing venlafaxine 75, 225, and 375 mg/day with
placeboA placebo is a sham medical intervention. In one common placebo procedure, a patient is given an inert sugar pill, told that it may improve his/her condition, but not told that it is in fact inert...
revealed a dose dependency for some of the more common adverse events associated with venlafaxine use. The rule for including events was to enumerate those that occurred at an incidence of 5% or more for at least one of the venlafaxine groups and for which the incidence was at least twice the placebo incidence for at least one venlafaxine group. Tests for potential dose relationships for these events (Cochran-Armitage Test, with a criterion of exact 2-sided p-value <=0.05) suggested a dose-dependency for several adverse events in this list, including chills, hypertension, anorexia, nausea, agitation, dizziness, somnolence, tremor, yawning, sweating, and abnormal ejaculation.
Memory loss
In a study of 70 patients that compared the tolerability of venlafaxine at standard doses, ranging from 75 to 300 mg, against relatively high doses (rarely prescribed), ranging from 375 to 600 mg per day, for treating DSM-IV major depressive disorder "failing memory" was reported in 44% of cases. The severity of venlafaxine-induced memory loss was also noted to increase with dose and length of treatment.
Discontinuation syndrome
In vitro studies revealed that venlafaxine has virtually no affinity for opiate, benzodiazepine, or N-methyl-D-aspartic acid (
NMDANMDA is an amino acid derivative acting as a specific agonist at the NMDA receptor, and therefore mimics the action of the neurotransmitter glutamate on that receptor...
) receptors. It has no significant CNS stimulant activity in rodents. In primate drug discrimination studies, venlafaxine showed no significant stimulant or depressant abuse liability.
Notwithstanding these findings, some patients stopping venlafaxine use experience
SSRI discontinuation syndromeSSRI discontinuation syndrome is the withdrawal that can occur during or following the interruption, lowering of dose, or discontinuation of regular SSRI or SNRI antidepressant drug use...
. This is especially noted if a patient misses a dose, but can also occur when reduction of dosage is done with a doctor's care. The high risk of discontinuation syndrome symptoms may reflect venlafaxine's short half-life. Missing even a single dose can induce discontinuation effects in some patients. Discontinuation is similar in nature to those of SSRIs such as
ParoxetineParoxetine is a selective serotonin reuptake inhibitor antidepressant. Marketing of the drug began in 1992 by the pharmaceutical company SmithKline Beecham, now GlaxoSmithKline...
(Paxil or Seroxat). Sudden discontinuation of venlafaxine particularly seemed to cause discontinuation symptoms during the first 3 days in a study of 18 patients. As reported in 2001 by Haddad in the journal
Drug Safety, "another strategy to consider is switching to fluoxetine, which may suppress the discontinuation symptoms, but which has little tendency to cause such symptoms itself," and then discontinuing that.
Although many other drugs can cause withdrawal symptoms which are not associated with addiction or dependence, for example, anticonvulsants, beta-blockers, nitrates,
diureticA diuretic is any drug that elevates the rate of urination and thus provides a means of forced diuresis. There are several categories of diuretics...
s, centrally acting antihypertensives, sympathomimetics,
heparinHeparin, a highly-sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule. It can also be used to form an inner anticoagulant surface on various experimental and medical devices such as test tubes and...
,
tamoxifenTamoxifen is an antagonist of the estrogen receptor in breast tissue. It has been the standard endocrine therapy for hormone-positive early breast cancer, although aromatase inhibitors have been proposed for postmenopausal women....
, dopaminergic agents, antipsychotics, and
lithiumLithium pharmacology refers to use of the lithium ion, Li
+, as a drug. A number of chemical salts of lithium are used medically as a mood stabilizing drug, primarily in the treatment of bipolar disorder, where they have a role in the treatment of depression and particularly of mania,...
, addiction or dependence is a more common effect described for drugs that (are thought to, or may) improve mental well-being.
name="pmid9081020">
Serotonin syndrome
The development of a potentially life-threatening
serotonin syndromeSerotonin syndrome is a potentially life-threatening adverse drug reaction that may occur following therapeutic drug use, inadvertent interactions between drugs, overdose of particular drugs, or the recreational use of certain drugs...
(also more recently classified as "serotonin toxicity") may occur with Venlafaxine treatment, particularly with concomitant use of serotonergic drugs (including SSRIs,
SNRISNRI may refer to:* Serotonin-norepinephrine reuptake inhibitor* Strategic Naval Research Institute...
s, and triptans) and with drugs that impair metabolism of serotonin (including MAOIs). Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, coma), autonomic instability (e.g., tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Venlafaxine-induced serotonin syndrome has also been reported when venlafxine has been taken in isolation in overdose. An abortive serotonin syndrome state, in which some but not all of the symptoms of the full serotonin syndrome are present, has been reported with venlafaxine at mid-range dosages (150 mg per day) A case of a patient with serotonin syndrome induced by low-dose venlafaxine (37.5 mg per day) has also been reported.
Combined serotonin toxicity and SSRI discontinuation syndrome
Venlafaxine may be particularly hazardous to those individuals who are susceptible to both venlafaxine-induced serotonin toxicity (also known as
serotonin syndromeSerotonin syndrome is a potentially life-threatening adverse drug reaction that may occur following therapeutic drug use, inadvertent interactions between drugs, overdose of particular drugs, or the recreational use of certain drugs...
) and
SSRI discontinuation syndromeSSRI discontinuation syndrome is the withdrawal that can occur during or following the interruption, lowering of dose, or discontinuation of regular SSRI or SNRI antidepressant drug use...
. In such cases individuals who have developed the potentially fatal serotonin toxicity and/or may be at risk of doing so may find cessation or dose reduction unachievable placing them at continuing risk. As it is not possible to determine which patients are likely to develop the most severe symptoms of the discontinuation syndrome before cessation or dose reduction is attempted, this dual risk requires that all patients are closely monitored during any increase in dosage (when the patient is most at risk of developing serotonin toxicity) and that such increases are carried out in the smallest incremental steps possible. Additionally, patients who recommence venlafaxine or revert to a higher dosage following a failed attempt to discontinue the drug or reduce dosage are another group with an increased risk of developing serotonin toxicity.
Available forms
Effexor is distributed in pentagon-shaped peach-colored tablets of 25 mg, 37.5 mg, 50 mg, 75 mg, and 100 mg. There is also an extended-release version distributed in capsules of 37.5 mg (gray/peach), 75 mg (peach), and 150 mg (brownish red).
Venlafaxine extended release (XR)
Venlafaxine extended release is chemically the same as normal venlafaxine. The extended release version (sometimes referred to as controlled release) controls the release of the drug into the
gastrointestinal tractThe human gastrointestinal tract , digestive tract, guts or gut is the system of organs within humans that takes in food, digests it to extract energy and nutrients, and expels the remaining matter...
over a longer period than normal venlafaxine. This results in a lower peak plasma concentration. Studies have shown that the extended release formula has a lower incidence of patients suffering from
nauseaNausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
as a side effect resulting in a lower number of patients stopping their treatment due to
nauseaNausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
. In Australia, New Zealand and Switzerland,
WyethWyeth, formerly known as American Home Products , was one of the largest pharmaceutical companies in the world. The company is based in Madison, New Jersey...
sells their venlafaxine XR tablets under the name "Efexor-XR" (note the spelling with one 'f', rather than "Effexor-XR"). In Brazil Medley sells a venlafaxine XR capsule under the brand name Alenthus XR. In September 2008, Osmotica Pharmaceuticals began marketing venlafaxine extended release tablets in the United States to compete with Wyeth's capsule-form, Effexor-XR.
Generic
Generic venlafaxine is available in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
as of August 2006 and in Canada as of December 2006. Generic forms of the extended-release version have been available in Canada as of January 2007 and currently include Co Venlafaxine XR (Cobalt Pharmaceuticals Inc.), Gen-Venlafaxine XR (Genpharm), Riva-Venlafaxine XR (Laboratoire Riva Inc.), Novo Venlafaxine XR (Novopharm Limited), PMS-Venlafaxine XR (Pharmascience Inc.), Ratio-Venlafaxine XR (ratiopharm), Viepax (in Israel) and Sandoz Venlafaxine XR (Sandoz Canada Inc.). Generic versions of both drug forms are available now in India. Generic versions are also available in the UK such as Vaxalin manufactured by RatioPharm GmbH.
Overdose
Most patients overdosing with venlafaxine develop only mild symptoms. However, severe toxicity is reported with the most common symptoms being
CNS depressionCentral nervous system depression or CNS depression refers to physiological depression of the central nervous system that can result in decreased rate of breathing, decreased heart rate, and loss of consciousness possibly leading to coma or death...
, serotonin toxicity,
seizureAn epileptic seizure is a transient symptom of excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms...
, or
cardiac conductionCardiac electrophysiology is the science of elucidating, diagnosing, and treating the electrical activities of the heart. The term is usually used to describe studies of such phenomena by invasive catheter recording of spontaneous activity as well as of cardiac responses to programmed electrical...
abnormalities. Venlafaxine's toxicity appears to be higher than other SSRIs, with a fatal toxic dose closer to that of the
tricyclic antidepressantTricyclic antidepressants are a class of psychoactive drugs used primarily as antidepressants, which were first discovered in the early 1950s, and subsequently introduced later in the decade...
s than the SSRIs. Doses of 900 mg or more are likely to cause moderate toxicity. Deaths have been reported following very large doses.
On May 31 2006, The
Medicines and Healthcare products Regulatory AgencyThe Medicines and Healthcare products Regulatory Agency is the UK government agency which is responsible for ensuring that medicines and medical devices work and are acceptably safe....
(MHRA) UK has concluded its review into all the latest safety evidence relating to venlafaxine particularly looked at the risks associated with overdose. The advice are, the need for specialist supervision in those severely depressed or hospitalized patients who need doses 300 mg or more; cardiac contra-indications are more targeted towards high risk groups; patients with uncontrolled hypertension should not take venlafaxine, and blood pressure monitoring is recommended for all patients; and updated advice on possible drug interactions.
On October 17, 2006 Wyeth and the FDA notified healthcare professionals of revisions to the Overdosage/Human Experience section of the prescribing information for Effexor (venlafaxine), indicated for treatment of major depressive disorder. In postmarketing experience, there have been reports of overdose with venlafaxine, occurring predominantly in combination with alcohol and/or other drugs. Published retrospective studies report that venlafaxine overdosage may be associated with an increased risk of fatal outcome compared to that observed with SSRI antidepressant products, but lower than that for tricyclic antidepressants. Healthcare professionals are advised to prescribe Effexor and Effexor XR in the smallest quantity of capsules consistent with good patient management to reduce the risk of overdose.
A report in the
British Medical JournalBMJ is a partially open access medical journal. It is among the most influential and widely read peer-reviewed general academic journals in the field of medicine in the world....
in 2002 by Dr. Nicholas Buckley and colleagues at the Department of Clinical Pharmacology and Toxicology,
CanberraCanberra is the capital city of Australia. With a population of over 345,000, it is Australia's largest inland city and the eighth largest Australian city overall. The city is located at the northern end of the Australian Capital Territory, south-west of Sydney, and north-east of Melbourne...
Hospital,
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the continental mainland , the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans...
studying fatal toxicity index (deaths per million prescriptions) found that venlafaxine's fatal toxicity is higher than that of other
serotoninergic antidepressants Selective serotonin reuptake inhibitors or serotonin-specific reuptake inhibitor are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, and some personality disorders...
but it is similar to that of some of the less toxic tricyclic antidepressants. Overall they found serious toxicity could occur following venlafaxine overdose with reports of deaths, arrythmias, and seizures. They did, however, state that this type of data is open to criticism pointing out that mortality data may be influenced by previous literature and that "less toxic" drugs may be preferentially prescribed to patients at higher risk of poisoning and suicide but they are also less likely to be listed as the sole cause of death from overdose. It also assumes that drugs are taken in overdose with similar frequency and in similar amounts. They suggested "clinicians need to consider whether factors in their patients reduce or compensate for this risk before prescribing venlafaxine."
The February 27, 2007 Vancouver Sun reported that the BC Drug and Poison Information Centre has alerted doctors that the drug poses a significant risk of death from overdose, saying that venlafaxine "appears more toxic than it was originally hoped". A doctor from the Department of Pharmacy Services College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina, reported on the death of a 39-year-old patient with a 30 g overdose. To put this into perspective, a patient would have to take over 66 of the infrequently prescribed 450 mg high dosage pills, or 400 of the commonly prescribed 75 mg pills.
Management of overdosage
There is no specific
antidoteAn antidote is a substance which can counteract a form of poisoning. The term ultimately derives from the Greek αντιδιδοναι antididonai, "given against"....
for venlafaxine and management is generally supportive, providing treatment for the immediate symptoms. Administration of activated charcoal can prevent absorption of the drug. Monitoring of cardiac rhythm and vital signs is indicated. Seizures are managed with
benzodiazepineA benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...
s or other anti-convulsants.
Forced diuresisForced diuresis may enhance the excretion of certain drugs in urine and is used to treat drug overdose or poisoning of these drugs and hemorrhagic cystitis.-Diuretics:...
,
hemodialysisIn medicine, hemodialysis is a method for removing waste products such as potassium and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...
,
exchange transfusionAn exchange transfusion is a medical treatment in which apheresis is used to remove one person's red blood cells or platelets and replace them with transfused blood products...
, or
hemoperfusionHemoperfusion is a medical process used to remove toxic substances from a patients blood. The technique involves passing large volumes of blood over an adsorbent substance. The adsorbent substance most commonly used in hemoperfusion are resins and activated carbon...
are unlikely to be of benefit in hastening the removal of venlafaxine, due to the drug's high
volume of distributionThe volume of distribution , also known as apparent volume of distribution, is a pharmacological term used to quantify the distribution of a medication between plasma and the rest of the body after oral or parenteral dosing. It is defined as the volume in which the amount of drug would need to be...
.
Mechanism of action
Venlafaxine is a bicyclic antidepressant, and is usually categorized as a
serotonin-norepinephrine reuptake inhibitorSerotonin-norepinephrine reuptake inhibitors are a class of antidepressant drugs used in the treatment of major depression and other mood disorders...
(SNRI), but it has been referred to as a serotonin-norepinephrine-dopamine reuptake inhibitor. It works by blocking the
transporter "reuptake" proteinsMonoamine transporters are structures in nerve-cell membranes that function as neurotransmitter transporters transferring monoamine neurotransmitters in or out of cells.-Types:There are several different monoamine transporters:*The dopamine transporter, DAT....
for key
neurotransmitterNeurotransmitters are endogenous chemicals which relay, amplify, and modulate signals between a neuron and another cell. Neurotransmitters are packaged into synaptic vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they...
s affecting mood, thereby leaving more active neurotransmitters in the synapse. The neurotransmitters affected are
serotoninSerotonin is a monoamine neurotransmitter. It is found extensively in the gastrointestinal tract of animals, and about 80 to 90 percent of the human body's total serotonin is located in the enterochromaffin cells in the gut, where it is used to regulate intestinal movements...
(5-hydroxytryptamine) and
norepinephrineNoradrenaline or norepinephrine is a catecholamine with dual roles as a hormone and a neurotransmitter....
(noradrenaline). Additionally, in high doses it weakly inhibits the reuptake of
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
, with recent evidence showing that the
norepinephrine transporterThe norepinephrine transporter or NET is a monoamine transporter that transports the neurotransmitter norepinephrine from the synapse back to its vesicles for storage until later use. It also appears to transport the neurotransmitter dopamine in the same way, but to a lesser degree...
also transports some
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
as well, implying that
SNRISNRI may refer to:* Serotonin-norepinephrine reuptake inhibitor* Strategic Naval Research Institute...
s may also increase
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
transmission. This is because
SNRISNRI may refer to:* Serotonin-norepinephrine reuptake inhibitor* Strategic Naval Research Institute...
s work by inhibiting reuptake, i.e. preventing the
serotoninSerotonin is a monoamine neurotransmitter. It is found extensively in the gastrointestinal tract of animals, and about 80 to 90 percent of the human body's total serotonin is located in the enterochromaffin cells in the gut, where it is used to regulate intestinal movements...
and norepinephrine transporters from taking their respective
neurotransmitterNeurotransmitters are endogenous chemicals which relay, amplify, and modulate signals between a neuron and another cell. Neurotransmitters are packaged into synaptic vesicles that cluster beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they...
s back to their storage vesicles for later use. If the
norepinephrine transporterThe norepinephrine transporter or NET is a monoamine transporter that transports the neurotransmitter norepinephrine from the synapse back to its vesicles for storage until later use. It also appears to transport the neurotransmitter dopamine in the same way, but to a lesser degree...
normally recycles some
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
too, then
SNRISNRI may refer to:* Serotonin-norepinephrine reuptake inhibitor* Strategic Naval Research Institute...
s will also enhance
dopaminergicDopaminergic means related to the neurotransmitter dopamine. For example, certain proteins such as the dopamine transporter , vesicular monoamine transporter 2 , and dopamine receptors can be classified as dopaminergic, and neurons which synthesize or contain dopamine and synapses with dopamine...
transmission. Therefore, the
antidepressantAn antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia. Drugs including the monoamine oxidase inhibitors , tricyclic antidepressants , tetracyclic antidepressants , selective serotonin reuptake inhibitors , and serotonin-norepinephrine...
effects associated with increasing norepinephrine levels may also be partly or largely due to the concurrent increase in
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
(particularly in the
prefrontal cortexThe prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
).
Pharmacokinetics
Venlafaxine is well absorbed with at least 92% of an oral dose being absorbed into systemic circulation. It is extensively metabolized in the liver via the
CYP2D6Cytochrome P450 2D6 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. Whilst CYP2D6 is involved in the oxidation of a wide range of substrates of all the CYPs, there is considerable...
isoenzyme to
desvenlafaxineDesvenlafaxine is an antidepressant of the serotonin-norepinephrine reuptake inhibitor class from Wyeth. Desvenlafaxine is a synthetic form of a known active metabolite of venlafaxine...
(
O-desmethylvenlafaxine), which is just as potent a serotonin-norepinephrine reuptake inhibitor as the parent compound, meaning that the differences in metabolism between extensive and poor metabolizers are not clinically important in terms of efficacy. Side effects, however, are reported to be more severe in
CYP2D6Cytochrome P450 2D6 , a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. Whilst CYP2D6 is involved in the oxidation of a wide range of substrates of all the CYPs, there is considerable...
poor metabolizers. Steady-state concentrations of venlafaxine and its
metaboliteMetabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. A secondary metabolite is not directly involved in those processes, but usually has...
are attained in the
bloodBlood is a specialized bodily fluid that delivers necessary substances to the body's cells — such as nutrients and oxygen — and transports waste products away from those same cells....
within 3 days. Therapeutic effects are usually achieved within 3 to 4 weeks. No accumulation of venlafaxine has been observed during chronic administration in healthy subjects. The primary route of excretion of venlafaxine and its metabolites is via the kidneys. The
half-lifeHalf-life is the period of time, for a substance undergoing decay, to decrease by half. The name originally was used to describe a characteristic of unstable atoms , but may apply to any quantity which follows a set-rate decay....
of venlafaxine is relatively short, therefore patients are directed to adhere to a strict medication routine, avoiding missing a dose. Even a single missed dose can result in the withdrawal symptoms.
Carriers of the (T;T) allele of rs2032583 SNP in the ABCB1 gene are 7x less likely to respond to Venlafaxine treatment. This genetic variant is present about two thirds of people of European descent and 80% to 90% of East Asians.
Drug interactions
Venlafaxine should be taken with caution when using
St John's wortSt John's wort is the plant species Hypericum perforatum, also known as Tipton's Weed or Klamath weed, but, with qualifiers, is used to refer to any species of the genus Hypericum. Therefore, H. perforatum is sometimes called Common St John's wort to differentiate it...
. Venlafaxine may lower the seizure threshold, and co-administration with other drugs that lower the seizure threshold such as
bupropionBupropion is an atypical antidepressant that acts as a norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist...
and
tramadolTramadol is a centrally acting analgesic, used for treating moderate to severe pain.Tramadol was developed by the German pharmaceutical company Grünenthal GmbH in the late 1970s.Tramadol possesses...
should be done with caution and at low doses.
There have been false positive
phencyclidinePhencyclidine , also known as angel dust and other street names, is a recreational, dissociative drug formerly used as an anaesthetic agent, exhibiting hallucinogenic and neurotoxic effects...
(PCP) results caused by Venlafaxine with certain on-site routine urine-based drug tests.
Although the synergistic effects may not be as bad as with other anti-depressants, it is still not recommended to take venlafaxine with alcohol.
Physical/chemical properties
The
chemical structureA chemical structure includes molecular geometry, electronic structure and crystal structure of a chemical compound. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together...
of venlafaxine is designated (R/S)-1-[2-(dimethylamino)-1-(4 methoxyphenyl)ethyl] cyclohexanol hydrochloride or (±)-1-[a [a- (dimethylamino)methyl] p-methoxybenzyl] cyclohexanol hydrochloride and it has the
empirical formulaIn chemistry, the empirical formula of a chemical compound is a simple expression of the relative numbers of each type of atom in it, or the simplest whole number ratio of atoms of each element present in a compound. An empirical formula makes no reference to isomerism, structure, or absolute...
of C
17H
27NO
2. It is a white to off-white crystalline solid. Venlafaxine is structurally and pharmacologically related to the atypical opioid
analgesicAn analgesic is any member of the diverse group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos...
TramadolTramadol is a centrally acting analgesic, used for treating moderate to severe pain.Tramadol was developed by the German pharmaceutical company Grünenthal GmbH in the late 1970s.Tramadol possesses...
and more distantly the newly-released opioid Nucynta(
TapentadolTapentadol is a centrally-acting analgesic with a unique dual mode of action as an agonist at the μ-opioid receptor and as a norepinephrine reuptake inhibitor. It is considered to have a potency between tramadol and morphine....
), but not to any of the conventional antidepressant drugs, including
tricyclic antidepressantTricyclic antidepressants are a class of psychoactive drugs used primarily as antidepressants, which were first discovered in the early 1950s, and subsequently introduced later in the decade...
s,
Selective serotonin reuptake inhibitor Selective serotonin reuptake inhibitors or serotonin-specific reuptake inhibitor are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, and some personality disorders...
s (SSRI),
Monoamine oxidase inhibitorMonoamine oxidase inhibitors are a class of powerful antidepressant drugs prescribed for the treatment of depression. They are particularly effective in treating atypical depression, and have also shown efficacy in smoking cessation....
s (MAOI), or
reversible inhibitors of monoamine oxidase ARIMA redirects here. For the Régiments d'Infanterie de Marine of the French Army, see Troupes de marineReversible inhibitors of monoamine oxidase type-A are a family of psychiatric drugs and natural compounds that inhibit monoamine oxidase temporarily and reversibly. They are mostly used for...
(RIMA).
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