Metabolism amobarbital

Enzymatic-metabolic activation (in part unknown)/phenobarbital-like promotion Hepatic enzyme induction, thyroid enzyme inhibition/axazepam, amobarbital, sulphonamides, thioureas Gastric secretory suppression, gastric atrophy induction (climetidine, omeprazole, butachlor... 

Aminopyrine, 234 Aminotetradine, 265 2-Aminothiazole, 247 2-Aminothiazole synthesis, 126 Amisotetradine, 266 Amobarbital, 268 Amopyroquine, 342 Amoxycillin, 414 Amphetamine, 37, 70 Ampicillin, 413 Amprolium, 264 Amytriptylene, 141, 404 Anabolic effects, 169 Androgens, discovery, 155 Androstanolone, 173 Androstenedione, 158, 176 Anesthesia, parenteral, 56 Angst, 363 Anileridine, 300 Aniline, metabolism. 111 Anisindandione, 147 Anovlar , 186 Antagonists, 20, 65 Antazoline, 242 Antibodies, 41... 

Amobarbital is extensively metabolized to polar metabolites in a process that is saturable and best described by zero-order kinetics at therapeutic doses.10 Two major metabolites are produced by hydroxylation and /V -glycosylation. 3 "-Hydroxyamobarbital possesses pharmacological activity. Approximately 92% of a single dose is excreted in the urine with 5% excreted in the feces over a 6-day period. Approximately 2% is excreted unchanged in the urine, 30 to 40% is excreted as free 3 -hydroxyamobarbital, 29% as /V-glycosylamobarbital, and 5% as the minor metabolite, 3 -car-boxyamobarbital. 

Kalow W, Tang BK, Kadar D, Endrenyi L, Chan F-Y. A method to study drug metabolism in populations racial differences in amobarbital metabolism. Clin Pharmacol Ther 1979 26 766-776. 

Another group of barbiturates is more rapidly metabolized by the liver. Their effects last six or seven hours, and they are called short-acting. They include amobarbital (Amytal), pentobarbital (Nembutal), hexobarbital (Sombulex), and secobarbital (Seconal). These drugs behave very much like alcohol, giving pleasant feelings in low doses, especially as they begin to take effect. There fore, some people seek them out to change the way they feel, and... 

Numerous barbiturates and oral hypoglycemic sulfonyl-ureas also have aliphatic side chains that arc su.sceptible to oxidation. Note that the sedative hypnotic amobarbital (Amytal) undergoes extensive to - I oxidation to the corresponding 3 -hydroxylated metabolite.Other barbiturates, such as pentobarbital, thiamylal,and secobarbital," reportedly are metabolized by way of a and to - I oxidation. The ri-propyl side chain attached to the oral hypoglycemic agent chlorpropamide (Diabinc.se) undergoes extensive to -I hydroxylation to yield the secondary alcohol 2 -hydroxy-chlorpropamide as a major urinary metabolite in humans. " ... 

The barbiturates undergo extensive hepatic metabolism in which the C5 substituents are transformed to alcohols, phenols, ketones, or carboxylic acids these metabolites may be excreted in urine in part as glucuronide conjugates. For some barbiturates (amobarbital and phenobarbital), N-glucosylation is an additional important metabolic trans-... 

BI< Tang, W Kalow. Amobarbital metabolism in man N-glucoside formation. Res Comm Chem Pathol Pharmacol 21 45—53, 1978. 

Barbiturates such as phenobarbital, amobarbital, and butabarbital induce glucuronyl transferase, an enzyme obligatory in bilirubin metabolism. Thus, they may be used in patients with chronic cholestasis. Phenobarbital is also used for lowering serum bilirubin in the neonate. 

Short Acting Amobarbital Pentobarbital Duration 3-6 hours. Both are metabolized by P450 enzymes in liver. Amobarbital is sometimes administered by psychiatrists during analysis or therapy. Prior to some neurosurgical procedures (e.g., temporal lobectomy for intractable seizures) amobarbital is injected unilaterally into the carotid artery to determine the dominant hemisphere of the brain. ... 

Conjugation of the heterocyclic nitrogen with glucosides. This unusual conjugation pathway can be as important as oxidative metabolism in the biotransformation of 5,5-disubstituted barbiturates (phenobarbital, amobarbital, pentobarbital). In humans, a pronounced product enantioselectivity is observed for excretion of these metabolites (47). 

Amobarbital Metabolism in Man. Determination of N-Hydroxyamobarbital and 3 -Hydroxyamobarbital in Urine by Gas Chromatography Chemical Ionization Mass Spectrometry Biomed. Mass Spectrom. 4(2) 73-76... 

Aliphatic Oxidation and O-Dealkylation - Cytochrome P-450 monoxygenases appear to be involved in a variety of aliphatic hydroxylations. One common pathway involves an initial w-hydroxylation as with pentobarbital, followed by further metabolism to the aldehyde and acid by dehydrogenases. Hydroxylation also frequently occurs at the penultimate carbon as in amobarbital l, at benzylic and allylic positions and at carbons bearing a heteroatom. Many examples of such oxidations are cited in a recent review.Hydroxylation at carbon bearing a heteroatom such as oxygen, nitrogen or sulfur leads to the so-called dealkylation reactions so common in drug metabolism. 

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