Amobarbital
Encyclopedia
Amobarbital is a drug that is a barbiturate
Barbiturate
Barbiturates are drugs that act as central nervous system depressants, and can therefore produce a wide spectrum of effects, from mild sedation to total anesthesia. They are also effective as anxiolytics, as hypnotics, and as anticonvulsants...

 derivative. It has sedative
Sedative
A sedative or tranquilizer is a substance that induces sedation by reducing irritability or excitement....

-hypnotic
Hypnotic
Hypnotic drugs are a class of psychoactives whose primary function is to induce sleep and to be used in the treatment of insomnia and in surgical anesthesia...

 and analgesic
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

 properties. It is a white crystalline powder with no odor and a slightly bitter taste. It was first synthesized in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 in 1923. If amobarbital is taken for extended periods of time, physical and psychological dependence
Substance dependence
The section about substance dependence in the Diagnostic and Statistical Manual of Mental Disorders does not use the word addiction at all. It explains:...

 can develop.

Pharmacology

According to an in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

study conducted at the University of British Columbia, amobarbital works by activating GABAA receptor
GABA A receptor
The GABAA receptor is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid , the major inhibitory neurotransmitter in the central nervous system. Upon activation, the GABAA receptor selectively conducts Cl- through its pore, resulting in...

s, which decreases input resistance, depresses burst
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...

 and tonic firing
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...

, especially in ventrobasal
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

 and intralaminar
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

 neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s, while at the same time increasing burst duration and mean conductance
Conductance
Conductance may refer to:* Electrical conductance, the ability for electricity to flow a certain path* Fluid conductance, the ability for fluid to transmit through materials* Thermal conductivity, the ability for temperatures to transmit through materials...

 at individual chloride channel
Chloride channel
Chloride channels are a superfamily of poorly understood ion channels consisting of approximately 13 members.Chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell...

s; this increases both the amplitude and decay time of inhibitory postsynaptic currents.

Furthermore, it is used in mitochondrial electron transport chain analysis. It is capable of binding CoQ and preventing the reduction of complex I, not unlike rotenone
Rotenone
Rotenone is an odorless chemical that is used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the roots and stems of several plants such as the jicama vine plant...

.

It has an in mice of 212 mg/kg s.c.

Metabolism

Amobarbital undergoes both hydroxylation
Hydroxylation
Hydroxylation is a chemical process that introduces a hydroxyl group into an organic compound. In biochemistry, hydroxylation reactions are often facilitated by enzymes called hydroxylases. Hydroxylation is the first step in the oxidative degradation of organic compounds in air...

 to form 3'-hydroxyamobarbital, and N-glucosidation
Glucoside
A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes....

 to form 1-(beta-D-glucopyranosyl)amobarbital.

Unapproved/off-label

  • When given slowly by an intravenous route, sodium amobarbital has a reputation for acting as a so-called truth serum
    Truth Serum
    Truth Serum is an independent comic book series created, written and drawn by author Jon Adams.-Overview:Originally published as a mini comic in 2001 and given away for free, it appeared as a three-issue mini series published by Slave Labor Graphics in 2002...

    . A person under the influence of the drug in this circumstance will relate information that he or she would otherwise "block." As such, the drug was first employed clinically by Dr. William Bleckwenn
    William Bleckwenn
    Dr. William Jefferson Bleckwenn was an American physician and psychiatrist who was instrumental in developing the treatment known as "narcoanalysis" or "narcosynthesis." The lay-description for that process is the administration of "truth serum."-Early years & education:Bleckwenn was born in...

     at the University of Wisconsin to circumvent inhibitions in psychiatric patients. It has been used to convict alleged murderers such as Andres English-Howard, who strangled his girlfriend to death but claimed innocence. He was surreptitiously administered the drug by his lawyer, and under the influence of it he revealed why he strangled her and under what circumstances. A year later he confessed on the witness stand and was convicted on the basis of these statements. He later committed suicide in his cell. The use of amobarbital as a truth serum has lost credibility due to the discovery that a subject can be coerced into having a 'false memory
    False memory
    False memory syndrome describes a condition in which a person's identity and relationships are affected by memories which are factually incorrect but are strongly believed. Peter J...

    ' of the event. In controlled doses, it is used in the narco analysis test to trace crime and criminals in modern forensics
    Forensics
    Forensic science is the application of a broad spectrum of sciences to answer questions of interest to a legal system. This may be in relation to a crime or a civil action...

    .
  • The drug may be used intravenously to interview patients with catatonic
    Catatonia
    Catatonia is a state of neurogenic motor immobility, and behavioral abnormality manifested by stupor. It was first described in 1874: Die Katatonie oder das Spannungsirresein ....

     mutism
    Speech disorder
    Speech disorders or speech impediments are a type of communication disorders where 'normal' speech is disrupted. This can mean stuttering, lisps, etc. Someone who is unable to speak due to a speech disorder is considered mute.-Classification:...

    , sometimes combined with caffeine
    Caffeine
    Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...

     to prevent sleep.
  • It was used by the United States armed forces
    United States armed forces
    The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...

     during World War II in an attempt to treat shell shock
    Shell Shock
    Shell Shock, also known as 82nd Marines Attack was a 1964 film by B-movie director John Hayes. The film takes place in Italy during World War II, and tells the story of a sergeant with his group of soldiers....

     and return soldiers to the front-line
    Front (military)
    A military front or battlefront is a contested armed frontier between opposing forces. This can be a local or tactical front, or it can range to a theater...

     duties.

Contraindications

The following drugs should be avoided when taking amobarbital:
  • Alcohol
  • Caffeine
    Caffeine
    Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...

  • Chloramphenicol
    Chloramphenicol
    Chloramphenicol is a bacteriostatic antimicrobial that became available in 1949. It is considered a prototypical broad-spectrum antibiotic, alongside the tetracyclines, and as it is both cheap and easy to manufacture it is frequently found as a drug of choice in the third world.Chloramphenicol is...

  • Chlorpromazine
    Chlorpromazine
    Chlorpromazine is a typical antipsychotic...

  • Cyclophosphamide
    Cyclophosphamide
    Cyclophosphamide , also known as cytophosphane, is a nitrogen mustard alkylating agent, from the oxazophorines group....

  • Ciclosporin
    Ciclosporin
    Ciclosporin , cyclosporine , cyclosporin , or cyclosporin A is an immunosuppressant drug widely used in post-allogeneic organ transplant to reduce the activity of the immune system, and therefore the risk of organ rejection...

  • Digitoxin
    Digitoxin
    Digitoxin is a cardiac glycoside. It has similar structure and effects to digoxin . Unlike digoxin , it is eliminated via the liver, so could be used in patients with poor or erratic kidney function. However, it is now rarely used in current Western medical practice...

  • Doxorubicin
    Doxorubicin
    Doxorubicin INN is a drug used in cancer chemotherapy. It is an anthracycline antibiotic, closely related to the natural product daunomycin, and like all anthracyclines, it works by intercalating DNA....

  • Doxycycline
    Doxycycline
    Doxycycline INN is a member of the tetracycline antibiotics group, and is commonly used to treat a variety of infections. Doxycycline is a semisynthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin...

  • Methoxyflurane
    Methoxyflurane
    Methoxyflurane is a halogenated ether that was in clinical use as an volatile inhalational anesthetic from its introduction by Joseph F. Artusio et al in 1960 until around 1974. It was first synthesized in the late 1940s by William T...

  • Metronidazole
    Metronidazole
    Metronidazole is a nitroimidazole antibiotic medication used particularly for anaerobic bacteria and protozoa. Metronidazole is an antibiotic, amebicide, and antiprotozoal....

  • Quinine
    Quinine
    Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...

  • Theophylline
    Theophylline
    Theophylline, also known as dimethylxanthine, is a methylxanthine drug used in therapy for respiratory diseases such as COPD and asthma under a variety of brand names. Because of its numerous side-effects, the drug is now rarely administered for clinical use. As a member of the xanthine family, it...

  • Warfarin
    Warfarin
    Warfarin is an anticoagulant. It is most likely to be the drug popularly referred to as a "blood thinner," yet this is a misnomer, since it does not affect the thickness or viscosity of blood...

  • Benzodiazepine
    Benzodiazepine
    A benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...

    s, such as diazepam
    Diazepam
    Diazepam , first marketed as Valium by Hoffmann-La Roche is a benzodiazepine drug. Diazepam is also marketed in Australia as Antenex. It is commonly used for treating anxiety, insomnia, seizures including status epilepticus, muscle spasms , restless legs syndrome, alcohol withdrawal,...

    , clonazepam
    Clonazepam
    Clonazepamis a benzodiazepine drug having anxiolytic, anticonvulsant, muscle relaxant, and hypnotic properties. It is marketed by Roche under the trade name Klonopin in the United States and Rivotril in Australia, Brazil, Canada and Europe...

     or nitrazepam
    Nitrazepam
    Nitrazepam is a type of benzodiazepine drug and is marketed in English-speaking countries under the following brand names: Alodorm, Arem, Insoma, Mogadon, Nitrados, Nitrazadon, Ormodon, Paxadorm, Remnos, and Somnite...

  • Antiepileptics, such as phenobarbital
    Phenobarbital
    Phenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide, and the oldest still commonly used. It also has sedative and hypnotic properties but, as with other barbiturates, has been superseded by the...

     or carbamazepine
    Carbamazepine
    Carbamazepine is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia...

  • Antihistamine
    Antihistamine
    An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...

    s, such as doxylamine
    Doxylamine
    Doxylamine is one of the many sedating antihistamines used by itself as a short-term sedative, and in combination with other drugs as a night-time cold and allergy relief drug...

     and clemastine
    Clemastine
    Clemastine, also known as meclastin, is an antihistamine and anticholinergic. Unlike loratadine or fexofenadine, clemastine is a sedating antihistamine, however it exhibits fewer other side effects than most of the widely used antihistamines. Clemastine is also classified as an antipruritic...

  • Narcotic
    Narcotic
    The term narcotic originally referred medically to any psychoactive compound with any sleep-inducing properties. In the United States of America it has since become associated with opioids, commonly morphine and heroin and their derivatives, such as hydrocodone. The term is, today, imprecisely...

     analgesic
    Analgesic
    An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

    s, such as morphine
    Morphine
    Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...

     and oxycodone
    Oxycodone
    Oxycodone is an opioid analgesic medication synthesized from opium-derived thebaine. It was developed in 1916 in Germany, as one of several new semi-synthetic opioids in an attempt to improve on the existing opioids: morphine, diacetylmorphine , and codeine.Oxycodone oral medications are generally...

  • Steroid
    Steroid
    A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

    s, such as prednisone
    Prednisone
    Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...

     and cortisone
    Cortisone
    Cortisone is a steroid hormone. It is one of the main hormones released by the adrenal gland in response to stress. In chemical structure, it is a corticosteroid closely related to corticosterone. It is used to treat a variety of ailments and can be administered intravenously, orally,...

  • Antidepressant
    Antidepressant
    An antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder. According to Gelder, Mayou &*Geddes people with a depressive illness will experience a therapeutic effect to their mood;...

    s
  • Antihypertensive
    Antihypertensive
    The antihypertensives are a class of drugs that are used to treat hypertension . Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from...

    s, such as atenolol and propranolol
  • Antiarrhythmics, such as verapamil
    Verapamil
    Verapamil is an L-type calcium channel blocker of the phenylalkylamine class. It has been used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, and most recently, cluster headaches. It is also an effective preventive medication for migraine...

     and digoxin
    Digoxin
    Digoxin INN , also known as digitalis, is a purified cardiac glycoside and extracted from the foxglove plant, Digitalis lanata. Its corresponding aglycone is digoxigenin, and its acetyl derivative is acetyldigoxin...



Amobarbital has been known to decrease the effects of hormonal birth control, sometimes to the point of uselessness. Being chemically related to phenobarbital
Phenobarbital
Phenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide, and the oldest still commonly used. It also has sedative and hypnotic properties but, as with other barbiturates, has been superseded by the...

, it might also do the same thing to digitoxin
Digitoxin
Digitoxin is a cardiac glycoside. It has similar structure and effects to digoxin . Unlike digoxin , it is eliminated via the liver, so could be used in patients with poor or erratic kidney function. However, it is now rarely used in current Western medical practice...

, a cardiac glycoside
Cardiac glycoside
Cardiac glycosides are drugs used in the treatment of congestive heart failure and cardiac arrhythmia. These glycosides are found as secondary metabolites in several plants, but also in some animals, such as the milkweed butterflies. -Function:...

.

In 1988, Miller et al. reported that amobarbital increases benzodiazepine receptor binding in vivo
In vivo
In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...

with less potency than secobarbital
Secobarbital
Secobarbital sodium is a barbiturate derivative drug that was first synthesized in 1928 in Germany. It possesses anaesthetic, anticonvulsant, sedative and hypnotic properties...

 and pentobarbital
Pentobarbital
Pentobarbital is a short-acting barbiturate that was first synthesized in 1928. Pentobarbital is available as both a free acid and a sodium salt, the former of which is only slightly soluble in water and ethanol....

 (in descending order), but greater than phenobarbital and barbital
Barbital
Barbital , also called barbitone, was the first commercially marketed barbiturate. It was used as a sleeping aid from 1903 until the mid-1950s. The chemical names for barbital are diethylmalonyl urea or diethylbarbituric acid...

 (in ascending order).

Overdose

Some side effects of overdose include confusion (severe); decrease in or loss of reflexes; drowsiness (severe); fever; irritability (continuing); low body temperature; poor judgment; shortness of breath or slow or troubled breathing; slow heartbeat; slurred speech; staggering; trouble in sleeping; unusual movements of the eyes; weakness (severe).

Chemistry

Amobarbital (5-ethyl-5-isoamylbarbituric acid), like all barbiturates, is synthesized by reacting malonic acid
Malonic acid
Malonic acid is a dicarboxylic acid with structure CH22. The ionised form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's ethyl ester...

 derivatives with urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 derivatives. In particular, in order to make amobarbital, α-ethyl-α-isoamylmalonic ester is reacted with urea (in the presence of sodium ethoxide
Sodium ethoxide
Sodium ethoxide is an alkoxide salt with the chemical formula C2H5ONa.-Preparation:It is commercially available as a white solid, or as a solution in ethanol. It is easily prepared in the laboratory by reacting sodium metal with ethanol:...

).
  • E. Lauraud, (1922).
  • H.A. Shonle, (1932).
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