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%. Up to 11.1% of patients actually experience drug interactions symptoms. An appraisal of drug interactions will help update our knowledge on the possible etiologies, mechanisms of action, adverse effects, clinical effects and desired advancements in therapies for drug interactions as well ways of managing same. Secondly, the systematic knowledge of drug interaction, especially at the level of absorption, elimination, transport and drug metabolism (pharmacokinetic profiles / variables) may help to prevent adverse effects. Predicting pharmacodynamic interactions often demands a deeper understanding of the mechanisms of effect even as Electronic prescribing systems have been found to be helpful in recent times. Also the rising cases of drug interactions in tropical and other regions of the world coupled with scarcity of literature in the subject area under study mandates the necessity for this write up, hence we write. Sources of literature were from PubMed, Science Direct, Scopus and Google Scholar etcetera. The knowledge of drug interaction at level of absorption, elimination, transport and drug metabolism may help prevent adverse effects. Predicting pharmacodynamic interactions often demands a deeper understanding of the mechanisms of action even as electronic prescribing systems may be helpful.