Diazepam pharmacokinetics and molecular data

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Pharmacokinetics

Mechanism

Absorption

Toxicity

Protein binding

Biotransformation

Half life

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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

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The content of this page is taken from the FDA package insert for this drug and should not be edited.