BARBITURATES

 

Examples:  Amobarbital, Butabarbital, Mephobarbital, Pentobarbital, Phenobarbital, Secobarbital

Mechanism of action and drug effects:  Bind to specific GABA_A receptor subunits at CNS neuronal synapses increasing duration of GABAmediated chloride ion channel opening and then enhance membrane hyperpolarization.

Pharmacological effects:  Dose-dependent depressant effects on the CNS including sedation and relief of anxiety, amnesia, hypnosis, anesthesia, coma and respiratory depression, steeper dose-response relationship than benzodiazepines.

Clinical applications:  Anesthesia (thiopental), insomnia (secobarbital), seizure disorders (phenobarbital).

Pharmacokinetics, toxicity and drug-drug interactions:  Half-lives from 4–60 h, oral activity.  Hepatic metabolism-phenobarbital 20% renal elimination.  Toxicity: Extensions of CNS depressant effects;  dependence liability benzodiazepines.  Interactions: Additive CNS depression with ethanol and many other drugs.  Induction of hepatic drug-metabolizing enzymes.

RELATED;

1.  DRUGS USED IN INDUCTION OF SLEEP

2.  BENZODIAZEPINES

3.  PHARMACOLOGY AND THERAPEUTICS

REFERENCES