Difference between revisions of "Amobarbital"

Latest revision as of 21:04, 21 September 2010

Amobarbital (formerly known as amylobarbitone) is a drug that is a barbiturate derivative. It has sedative-hypnotic and analgesic properties. It is a white crystalline powder with no odor and a slightly bitter taste. It was first synthesized in Germany in 1923. If amobarbital is taken for extended periods of time, physical and psychological dependence can develop.

Pharmacology

According to an in vitro study conducted at the University of British Columbia, amobarbital works by activating GABA_A receptors, which decreases input resistance, depresses burst and tonic firing, especially in ventrobasal and intralaminar neurons, while at the same time increasing burst duration and mean conductance at individual chloride channels; this increases both the amplitude and decay time of inhibitory postsynaptic currents.^[1]

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.

It has an LD₅₀ in mice of 212 mg/kg s.c.

Metabolism

Amobarbital undergoes both hydroxylation to form 3'-hydroxyamobarbital,^[2] and N-glucosidation^[3] to form 1-(beta-D-glucopyranosyl)amobarbital.^[4]

Indications

Approved

• Amnesia
• Insomnia
• Epilepsy
• Wada test

Unapproved/off-label

• When given slowly by an intravenous route, sodium amobarbital has a reputation for having activity as a so-called truth serum. 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 at the University of Wisconsin to circumvent inhibitions in psychiatric patients.^[5] 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 attorney, and under the influence of it he revealed why he strangled her and under which circumstances. A year later he confessed, on the stand, and was convicted on the basis of these statements; he later committed suicide in his cell.^[6] The use of amobarbital as a truth serum has lost credibility due to the discovery^{[citation needed]} that the subject can be coerced into having a 'false memory' of the event. In controlled doses, it is used in the narco analysis test to trace crime and criminals in modern forensics.^{[citation needed]}

• The drug may be used intravenously to interview patients with catatonic mutism, sometimes combined with caffeine to prevent sleep.^[7]

• It was used by the U.S. Army during World War II's Battle of the Bulge to get shell-shocked GI's back to the frontline.^[8]

Contraindications

The following drugs should be avoided when taking amobarbital:

• Alcohol
• Caffeine^{[citation needed]}
• Chloramphenicol
• Chlorpromazine
• Cyclophosphamide
• Ciclosporin
• Digitoxin
• Doxorubicin
• Doxycycline
• Methoxyflurane
• Metronidazole
• Quinine
• Theophylline
• Warfarin
• Benzodiazepines, such as diazepam, clonazepam or nitrazepam
• Antiepileptics, such as phenobarbital or carbamazepine
• Antihistamines, such as doxylamine and clemastine
• Narcotic analgesics, such as morphine and oxycodone
• Steroids, such as prednisone and cortisone
• Antidepressants^{[citation needed]}
• Antihypertensives, such as atenolol and propranolol
• Antiarrhythmics, such as verapamil and digoxin

Amobarbital has been known to decrease the effects of hormonal birth control, sometimes to the point of uselessness. Being chemically related to phenobarbital, it might also do the same thing to digitoxin, a cardiac glycoside.

In 1988, Miller et al. reported that amobarbital increases benzodiazepine receptor binding in vivo with less potency than secobarbital and pentobarbital (in descending order), but greater than phenobarbital and barbital (in ascending order).^[9]

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). Death can be a result, as in the case of the Hollywood actor Robert Walker.

See also

• Depressants
• Barbiturates
• Wada test
• Blue 88

References and end notes

1. Controlled Substances in Schedule II Office of Diversion Control, Drug Enforcement Administration.
2. Controlled Substances in Schedule III Office of Diversion Control, Drug Enforcement Administration.

External links

de:Amobarbital gl:Amobarbital hi:एमोबार्बिटल ja:アモバルビタール pt:Amobarbital ru:Амобарбитал sk:Amytal sl:Amobarbiton fi:Amobarbitaali sv:Amobarbital

1. ↑ Kim HS, Wan X, Mathers DA, Puil E. "Selective GABA-receptor actions of amobarbital on thalamic neurons." British Journal of Pharmacology. 2004 Oct;143(4):485-94. Epub 2004 Sep 20. PMID 15381635
2. ↑ Maynert EW. "The alcoholic metabolites of pentobarbital and amobarbital in man." Journal of Pharmacology and Experimental Therapeutics. 1965 Oct;150(1):118-21. PMID 5855308
3. ↑ Tang BK, Kalow W, Grey AA. "Amobarbital metabolism in man: N-glucoside formation." Research Communications in Chemical Pathology and Pharmacology. 1978 Jul;21(1):45-53. PMID 684279
4. ↑ Soine PJ, Soine WH. "High-performance liquid chromatographic determination of the diastereomers of 1-(beta-D-glucopyranosyl)amobarbital in urine." Journal of Chromatography. 1987 Nov 27;422:309-14. PMID 3437019
5. ↑ Bleckwenn WJ Sodium amytal in certain nervous and mental conditions. Wis Med J 1930; 29: 693-696.
6. ↑ Truth Serum: A Possible Weapon, 60 Minutes, April 23, 2003.
7. ↑ McCall WV. "The addition of intravenous caffeine during an amobarbital interview." Journal of Psychiatry & Neuroscience. 1992 Nov;17(5):195-7. PMID 1489761
8. ↑ Use of sodium amytal during WWII
9. ↑ Miller LG, Deutsch SI, Greenblatt DJ, Paul SM, Shader RI (1988). "Acute barbiturate administration increases benzodiazepine receptor binding in vivo". Psychopharmacology (Berl). 96 (3): 385–90. doi:10.1007/BF00216067. CS1 maint: Multiple names: authors list (link) PMID 2906155