Pharmacological Review of Drug Interactions

Drug interaction (DI) occurs when the effects of one drug are altered by the presence of another drug, herbal medicine, foods, drink or by some environmental or chemical agents†. Any time a drug is administered with another prescription or over the counter drug, herb or food item, there is the risk of interactions which may be potentially dangerous. Drug-drug interaction increases with the number of drugs used concomitantly. The drug whose activity is effected by such interaction is referred to as the “Object drug†while the agent that eventually precipitates such an interaction is referred to as the “Precipitant / Perpetrator drug†. It is worthy of note that drug interactions may cause drugs to be less effective, may induce unexpected side effects or rarely even increase the action of a particular drug. Many drug interactions have been found to be harmful. Approximately 3– 26% of adverse reactions related to hospital admissions are due to drug-drug interactions while, global prevalence of potentially inappropriate prescribing ranges from 13–35%.