What factors may affect the absorption and distribution of sedative-hypnotic drugs? What is the clinical significance thereof?

• Lipophilicity, which determines the rate at which a particular sedative-hypnotic enters the CNS. 

What is meant by redistribution and what is the significance thereof?

• Redistribution occurs with highly lipid soluble drugs that distribute to the brain, heart and kidney then  immediately followed by muscles and fats. This makes them suitable for continuous infusion.

How are the BDs metabolized? Name the various steps in the process.

• Dealkylation
• Oxidation
• Conjugation

Which BDs are converted to active metabolites? What is the significance thereof?

• Diazepam, chlorazepate, prazepam, chlordiazepoxide and ketazolam (more lipophilic) are converted to active metabolites which contributes to their extended duration of action. 

Which BDs are not dependent on the cytochrome P450 oxidative enzymes for metabolism? What are the advantages thereof?

• Oxazepam, lorazepam, temazepam and lormetazepam (less lipophilic), these drugs are drugs of choice where  cytochrome P450 activity is reduced e.g elderly, neonates and liver cirrhosis.

What is enzyme induction? Which of the sedative hypnotic drugs are known for this?. What is the clinical significance of enzyme induction?

Enzyme induction is  increase in the biosynthesis of catalytically active enzyme, Enzyme induction increases metabolism of drugs and may lead to therapeutic levels not being reached.