Diazepam pharmacokinetics and molecular data

Pharmacokinetics
Mechanism Absorption Toxicity Protein binding Biotransformation Half life

Mechanism
Benzodiazepines bind nonspecifically to benzodiazepine receptors which mediate sleep, affects muscle relaxation, anticonvulsant activity, motor coordination, and memory. As benzodiazepine receptors are thought to be coupled to gamma-aminobutyric acid-A (GABAA) receptors, this enhances the effects of GABA by increasing GABA affinity for the GABA receptor. Binding of GABA to the site opens the chloride channel, resulting in a hyperpolarized cell membrane that prevents further excitation of the cell. Return to top

Absorption
Essentially complete, with a bioavailability of 93%. Return to top

Toxicity
Symptoms of overdose include somnolence, confusion, coma, and diminished reflexes. Respiration, pulse and blood pressure should be monitored. Return to top

Protein binding
Both diazepam and its major active metabolite desmethyldiazepam bind extensively to plasma proteins (95-98%). Return to top

Biotransformation
Hepatic via the Cytochrome P450 enzyme system. The main active metabolite is desmethyldiazepam, in addition to minor active metabolites including temazepam and oxazepam. Return to top

Half life
Biphasic 1-2 days and 2-5 days, active metabolites with long half lives. Return to top