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

The polarity of the drug affects the absorption of the drug. BD’s are lipophilic and therefor can enter fat cells where it is stored and graduately released into the bloodstream to maintain drug concentration. BD’s are fat soluble and move through the bloodstream quickly and passes through the blood brain barrier for a fast onset of action.

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

Redistribution means that the drug moves from the body to the brain and from the brain to the body, the significance there of that for example Thiopental with this characteristic can be used for retrograde amnesia due to its lipophilicity, also the drug then is stored in fat cells where it acts as a depot to maintain the drug concentration

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

BDs are metabolized via 3 steps :

- Dealkylation – Active metabolites are being formed.

-Oxidation – Cytochrome P450: forms the active metabolites.

- Conjugation – Inactive metabolite are being formed.

The first 2 steps are Phase 1 and the Last step is Phase 2.

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

Diasepam, Chloorasepate, Prasepam, Chlordiapoxide, Cetazolam. These drugs are known as pro drugs and only has a pharmacological effect when they are in their active form. There drugs will therefor (after being metabolised via phase 1) have an hypnotic-sedative or anxiolytic effect in the central nervous system.

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

Oksasepam, Lorasepam, temazepam and lormetazepam. The advantages of this is that the drug is immediately in its active form and will have an effect on the body. These drugs will be ideal in patients who has a low P450 cytochrome count.

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

Enzyme induction can be defined as the increase in the biosynthesis of catalytically active enzyme following exposure of the organism to chemical agents or physiological conditions (Comprehensive Toxicology (Third Edition), 2018). .There drugs will therefor (after being metabolised via phase 1) have an hypnotic-sedative or anxiolytic effect in the central nervous system.