Butabarbital
Butabarbital
Brand Names: Butisol®, Buticaps® | Busodium™
Classification:
Psychotropic Agents
» Anxiolytics, Sedatives, and Hypnotics
» Barbiturates
NOTE: Butabarbital is a schedule C-III controlled substance.
Description: Butabarbital is an oral barbiturate with an intermediate duration of action. It is similar to amobarbital. Butabarbital is clinically used for daytime sedation, to relieve preoperative anxiety and provide sedation, and in the short-term treatment of insomnia. Butabarbital was approved by the FDA in June 1939. Butabarbital is a schedule III controlled substance.
Mechanism of Action: The exact mechanism by which butabarbital exerts its effects is not known. Butabarbital suppresses the spread of seizure activity in the cortex, thalamus, and limbic systems. In general, a nonselective depressant effect occurs throughout the CNS due to a decrease in both pre- and postsynaptic excitability. The sedative-hypnotic effects of butabarbital are related to its inhibition of ascending conduction in the reticular formation, which controls CNS arousal. This inhibition results in depression of the sensory cortex; decreased motor activity; altered cerebral function; and production of drowsiness, sedation, and hypnosis. In the motor cortex, butabarbital increases the threshold for electrical stimulation, which contributes to its anticonvulsant properties. It has been suggested that the above sedative-hypnotic and anticonvulsant effects of barbiturates may be due to their ability to mimic the inhibitory synaptic action of gamma-aminobutyric acid.
 Butisol Sodium Tablets (Tab 30 mg)
Hypnotic doses of butabarbital cause respiratory depression as in normal sleep, but large doses have marked effects, which are also seen with excessively rapid IV injection. Sedative doses also reduce motility and tone in the GI tract due to a central depressant effect. Barbiturates have been shown to reduce the REM period of sleep. Butabarbital is also active in lowering the serum bilirubin concentrations in neonates and patients with chronic cholestasis. This effect is believed to be due to induction of glucuronyl transferase, the enzyme responsible for conjugation of bilirubin.
Pharmacokinetics: Absorption of butabarbital from the GI tract is good following oral administration. The rate of absorption is faster if the barbiturate is taken well diluted or on an empty stomach. Sodium salts are more rapidly absorbed. Concentrations in excess of 50 mcg/mL generally will result in deep coma and possibly death. Butabarbital has an onset of action of around 45 - 60 minutes and a duration of about 6 - 8 hours. Distribution is rapid to all body fluids and tissues. Lipid solubility is a key factor in distribution; the more lipid-soluble, the more rapid the penetration into tissues. Butabarbital has low binding to plasma proteins. Metabolism takes place in the liver to produce an inactive metabolite. Excretion is via the kidneys, mainly as the inactive metabolite, with only a very small portion excreted as unchanged drug.
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[ Revised 4/28/2006 10:04:00 AM ]
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