Drug–drug interaction knowledge to save the patient from iatrogenic disease and to improve the diagnostic process

A drug interaction occurs when a patient’s response to a drug is modifed by other drugs, disease, food, nutritional supplements, formulation excipients, and environmental factors, and it may be harmful or benefcial. Altered compliance, pharmaceutic, pharmacokinetic and pharmacodynamic interactions are the main mechanisms involved. A huge part of the related literature deals with harmful potential drug–drug interactions (PDDIs), but polypharmacy is potentially problematic rather than being often inappropriate. In fact, sometimes multiple drug regimens represent a price worth paying for health benefts.