Question

1. List the three factors that interact to produce drug effects, and give an example of each factor.

Answer 1

Factors that interact the drug effect cause drug interaction, ultimately affecting the ADME of the drug means absorption distribution, metabolism and excretion of the drug and thus affecting the overall effect of drug.

The food can also affect the drug effect. Example. Milk with tetracycline cause reduced drug absorption of tetracycline because the ionic content of milk like Ca++ make complex with the tetracycline.

Another type of drug interaction is metabolic type, in which one drug or the factor inhibit or stimulate the metabolism of another drug altering the bioavailability of the target drug and hence altering its overall effect. For the example: phenobarbitone increases the metabolism of warfarin thus reducing the anticoagulant effect of drug warfarin.

The third type of major drug interaction is disease - drug interaction in which the certain disease state affects the overall effect of the particular drug. Example: the toxicity of amino glycosides in renal impaired patient.