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Promethazine is a first-generation H1 receptor antagonist, antihistamine
Antihistamine

An H1 antagonist is a histamine antagonist of the histamine H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergy....
 and antiemetic
Antiemetic

An antiemetic is a medication that is effective against vomiting and nausea. Anti-emetics are typically used to treat motion sickness and the Adverse effect of opioid analgesics, general anaesthetics and chemotherapy directed against cancer....
 medication. It can also have strong sedative
Sedative

A sedative is a substance that induces sedation by reducing irritability or excitement.At higher doses it may result in slurred speech, staggering gait , poor judgment, and slow, uncertain reflexes....
 effects although it is rarely used specifically for this. It is a prescription drug
Prescription drug

A prescription drug is a medication that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription....
 in the United States, but is available over the counter
Over-the-counter drug

Over-the-counter drugs are medications that may be sold to a customer without a medical prescription. The term "over-the-counter" is somewhat counter-intuitive, since these items can often be found on the shelves of stores and bought like any other packaged product in some countries in contrast to prescription drug which are more likely to l...
 in the United Kingdom, Switzerland, and many other countries (brand names Phenergan, Promethegan, Romergan, Fargan, Farganesse, Prothiazine, Avomine, Atosil, Receptozine, Lergigan).

Chemically, promethazine hydrochloride
Hydrochloride

In chemistry, hydrochlorides are salt s resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic Base . This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid....
 (HCl) appears as a white to faint yellow crystaline powder which is practically odorless.






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Encyclopedia


Promethazine is a first-generation H1 receptor antagonist, antihistamine
Antihistamine

An H1 antagonist is a histamine antagonist of the histamine H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergy....
 and antiemetic
Antiemetic

An antiemetic is a medication that is effective against vomiting and nausea. Anti-emetics are typically used to treat motion sickness and the Adverse effect of opioid analgesics, general anaesthetics and chemotherapy directed against cancer....
 medication. It can also have strong sedative
Sedative

A sedative is a substance that induces sedation by reducing irritability or excitement.At higher doses it may result in slurred speech, staggering gait , poor judgment, and slow, uncertain reflexes....
 effects although it is rarely used specifically for this. It is a prescription drug
Prescription drug

A prescription drug is a medication that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription....
 in the United States, but is available over the counter
Over-the-counter drug

Over-the-counter drugs are medications that may be sold to a customer without a medical prescription. The term "over-the-counter" is somewhat counter-intuitive, since these items can often be found on the shelves of stores and bought like any other packaged product in some countries in contrast to prescription drug which are more likely to l...
 in the United Kingdom, Switzerland, and many other countries (brand names Phenergan, Promethegan, Romergan, Fargan, Farganesse, Prothiazine, Avomine, Atosil, Receptozine, Lergigan).

Chemically, promethazine hydrochloride
Hydrochloride

In chemistry, hydrochlorides are salt s resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic Base . This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid....
 (HCl) appears as a white to faint yellow crystaline powder which is practically odorless. Slow oxidation may occur upon prolonged exposure to air usually causing blue discoloration. Promethazine as the hydrochloride salt is freely soluble in water and somewhat soluble in alcohol.

Indications

  • As a sedative
    Sedative

    A sedative is a substance that induces sedation by reducing irritability or excitement.At higher doses it may result in slurred speech, staggering gait , poor judgment, and slow, uncertain reflexes....
    .
  • For preoperative sedation
    Sedation

    Sedation is a medical procedure involving the administration of sedative drugs, generally to facilitate a medical procedure with local anaesthesia....
     and to counteract postnarcotic
    Narcotic

    The term narcotic is believed to have been coined by the Greek physician Galen to refer to agents that benumb or deaden, causing loss of feeling or paralysis....
     nausea
    Nausea

    Nausea is the sensation of unease and discomfort in the stomach with an urge to vomit....
    .
  • As antiallergic medication to combat hay fever
    Hay Fever

    Hay Fever is a comic play written by No?l Coward in 1924 and first produced in 1925 with Marie Tempest as the first Judith Bliss. Best described as a cross between high farce and a comedy of manners, the play is set in an English country house in the 1920s, and deals with the four eccentric members of the Bliss family and their outlandish b...
    , allergic rhinitis
    Rhinitis

    Rhinitis, commonly known as a runny nose, is the medical term describing irritation and inflammation of some internal areas of the nose. The primary symptom of rhinitis is nasal...
    , etc. To treat allergic reactions it can be given alone or in combination with oral
    Mouth

    The mouth, buccal cavity, or oral cavity is the first portion of the alimentary canal that receives food and begins digestion by mechanically breaking up the solid food particles into smaller pieces and mixing them with saliva....
     decongestant
    Decongestant

    A decongestant is a broad class of medications used to relieve nasal congestion. Generally, they work by reducing swelling of the mucous membranes in the nose passages....
    s like pseudoephedrine
    Pseudoephedrine

    Pseudoephedrine is a sympathomimetic amine amine commonly used as a decongestant. The salts pseudoephedrine hydrochloride and pseudoephedrine sulfate are found in many Over-the-counter drug preparations either as single-ingredient preparations, or more commonly in combination with antihistamines, paracetamol and/or ibuprofen....
    .
  • As an adjunct
    Adjunct

    Adjunct may refer to:* Adjunct , words used as modifiers* Adjuncts, sources of sugar used in brewing...
     treatment
    Treatment

    Treatment is most often used to mean a process of modifying or altering something, and depending on context may be used in an unqualified form to refer to any of the following:...
     for anaphylactoid
    Anaphylaxis

    Anaphylaxis is an acute Circulatory system and very severe Type I hypersensitivity allergy reaction in humans and other mammals. The term comes from the Greek words a?a ana and f??a??? phylaxis ....
     condition
    Condition

    Condition can refer to:* A state of being.* Living condition, see Quality of life.* In health, a disease, such as a heart condition, as in Medical condition....
    s (IM
    IM

    IM or Im may refer to:* .im, Internet country code for the Isle of Man* Im , a giant in Norse mythology* Im * Im, a subtype of irregular galaxy...
    /IV
    IV

    IV as the Roman numerals for 4 may refer to:*Led Zeppelin IV, the fourth album by Led Zeppelin containing the popular song "Stairway to Heaven"...
     route
    Route

    Route may refer to:*GPS route, a series of one or more GPS waypoints*Road numberSee also*Routing ...
     preferred).
  • Together with codeine
    Codeine

    Codeine or methylmorphine is an opiate used for its analgesic, Cough medicine and Antidiarrhoeal properties. It is by far the most widely used opiate in the world and probably the most commonly used drug overall according to numerous reports over the years by organizations such as the World Health Organization and its League of Nations...
     or dextromethorphan
    Dextromethorphan

    Dextromethorphan is an antitussive drug. It is one of the active ingredients used to prevent coughs in many Over-the-counter drug common cold and cough medicines....
     against cough
    Cough

    A cough , in medicine, is a sudden and often repetitively occurring defense reflex which helps to clear the large breathing passages from excess secretions, irritants, foreign particles and microbes....
    .
  • As a motion sickness
    Motion sickness

    Motion sickness or kinetosis is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement....
     or seasickness remedy when used with Ephedrine
    Ephedrine

    Ephedrine is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia....
     or Pseudoephedrine
    Pseudoephedrine

    Pseudoephedrine is a sympathomimetic amine amine commonly used as a decongestant. The salts pseudoephedrine hydrochloride and pseudoephedrine sulfate are found in many Over-the-counter drug preparations either as single-ingredient preparations, or more commonly in combination with antihistamines, paracetamol and/or ibuprofen....
    .
  • To combat moderate to severe morning sickness
    Morning sickness

    Morning sickness, also called nausea gravidarum, nausea, vomiting of pregnancy , or pregnancy sickness is a condition that affects more than half of all pregnant women, as well as some women who use hormonal contraception or hormone replacement therapy....
     and hyperemesis gravidarum
    Hyperemesis gravidarum

    Hyperemesis gravidarum is a severe form of morning sickness, with unrelenting, excessive pregnancy-related nausea and/or vomiting that prevents adequate intake of food and fluids. Hyperemesis is considered a rare complication of pregnancy but, because nausea and vomiting during pregnancy exist on a continuum, there is often not a good d...
    . In the UK promethazine
    Promethazine

    Promethazine is a first-generation histamine H1 receptor antagonist, antihistamine and antiemetic medication. It can also have strong sedative effects although it is rarely used specifically for this....
     is drug
    Drug

    A drug, broadly speaking, is any chemical substance that, when absorbed into the body of a living organism, alters normal bodily function....
     of first choice, being preferred as an older drug with which there is a greater experience of use in pregnancy
    Pregnancy

    Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or Multiple birth....
     (second line being metoclopramide
    Metoclopramide

    Metoclopramide is a potent dopamine receptor antagonist used for its antiemetic and prokinetic properties. Thus it is primarily used to treat nausea and vomiting, and to facilitate gastric emptying in patients with gastroparesis....
     or prochlorperazine
    Prochlorperazine

    Prochlorperazine is a drug that belongs to the phenothiazine class of antipsychotic agents that are used for the treatment of nausea and vertigo ....
    ).
  • Previously it was used as an antipsychotic
    Antipsychotic

    Antipsychotics are a group of psychoactive drugs commonly but not exclusively used to treat psychosis, which is typified by schizophrenia. Over time a wide range of antipsychotics have been developed....
    ., although it is generally not administered for this purpose now; promethazine has only approximately 1/10 of the antipsychotic strength of chlorpromazine
    Chlorpromazine

    Chlorpromazine is a phenothiazine antipsychotic, and the oldest in the antipsychotic family of drugs. It is a typical antipsychotic. It is principally used in the treatment of schizophrenia, though it has also been used to treat severe manic episodes in people with bipolar disorder....
    .

Contraindications

  • Promethazine should not be given to children under two years of age; there is potential for fatal respiratory depression in this age group.
  • Hypersensitivity to phenothiazines
  • Closed angle glaucoma
    Glaucoma

    Glaucoma is a group of diseases of the optic nerve involving loss of ganglion cell in a characteristic pattern of optic atrophy. Raised intraocular pressure is a significant risk factor for developing glaucoma ....
  • Intoxication with alcohol or other central depressants
  • Severe hypotension
    Hypotension

    In physiology and medicine, hypotension refers to an abnormally low blood pressure. This is best understood as a physiologic state, rather than a disease....
     or shock
  • Coma
    Coma

    In medicine, a coma is a profound state of unconsciousness. A comatose person cannot be awakened, fails to respond normally to pain or light, does not have sleep-wake cycles, and does not take voluntary actions....
     due to any reason
  • Severely impaired liver function
  • Urine hesitancy due to enlargement of the prostate gland


Mechanism of action

  • Promethazine is a phenothiazine derivative that competitively blocks histamine H1 receptors without blocking the secretion of histamine.
  • It has sedative, anti-motion-sickness, anti-emetic, and anti-cholinergic effects


Side effects

Some common side effects
Adverse effect (medicine)

In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as chemotherapy or surgery....
 include:
  • Blurred vision
  • Confusion in the elderly
  • Drowsiness, dizziness, fatigue, more rarely vertigo
    Vertigo (medical)

    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....
  • Dry mouth
  • Seizures (extremely rare)
  • Neuroleptic malignant syndrome
    Neuroleptic malignant syndrome

    Neuroleptic malignant syndrome is a life-threatening neurological disorder most often caused by an adverse reaction to antipsychotic. It generally presents with muscle rigidity, fever, autonomic instability and cognitive changes such as delirium, and is associated with elevated creatine phosphokinase ....
     (extremely rare)
  • Respiratory depression in patients under age of 2 and in those with severely compromised pulmonal function
  • Constipation
  • Euphoria (very rare with high IV doses and/or coadministration with opioids/CNS depressants)
  • Restless legs
  • Paresthesia
    Paresthesia

    Paresthesia is a sensation of tingling, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a human limb being "asleep" ....


It is recommended that promethazine only be given through an existing intravenous set in a large vein and diluted to concentration no greater than 25mg per mL, not to exceed a rate of administration of 25mg a min. Serious complications including those listed above have resulted from improper parenteral administration, including those requiring surgical intervention and amputation.

Laboratory examinations

All patients should have their blood pressure
Blood pressure

Blood pressure is the pressure exerted by circulating blood on the walls of blood vessels, and constitutes one of the principal vital signs. The pressure of the circulating blood decreases as it moves away from the heart through artery and capillary, and toward the heart through veins....
 measured frequently. During long-term therapy, blood cell counts, liver function studies, EKG, and EEG
EEG

EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
 are recommended. The intervals should be determined according to the risk profile of the patient. In high doses, promethazine can create auditory and visual hallucinations causing panic and intense fear.

Case Law


The U.S. Supreme Court accepted a case involving promethazine that influences product liability
Product liability

Product liability is the area of law in which manufacturers, distributors, suppliers, retailers, and others who make products available to the public are held responsible for the injuries those products cause....
. A woman suffering from a migraine was administered Wyeth
Wyeth

Wyeth, formerly known as American Home Products , is one of the largest pharmaceutical company in the world. The company is based in Madison, New Jersey....
's Phenergan via IV push. The drug was injected improperly resulting in gangrene
Gangrene

For the American football team nicknamed "Gang Green," see New York Jets.Gangrene is a complication of necrosis characterized by the decay of biological tissues, which become black and malodorous....
 and subsequent amputation of her right arm below the elbow. A state jury awarded her $6 million in punitive damages. The case was appealed to the Supreme Court on grounds of federal pre-emption
Preemption (law)

In the legal system of the United States, preemption generally refers to the displacing effect that US Federal government law will have on a conflicting or inconsistent US states law....
 and substantive due process. The Supreme Court upheld the lower courts' rulings stating that "Wyeth could have unilaterally added a stronger warning about IV-push administration" without acting in opposition to federal law.

External links