Drug Interactions Pharmacology: A Narrative Review

Thesimultaneous prescription of multiple drugs used in therapeutic schemes canresult in drug interactions, with desirable or undesirable effects. Thus, theobjective of this study was to describe the mechanisms involved in clinicallyrelevant drug interactions. This is a narrative review in which studiespublished in PUBMED and the VHL were searched in the following databases:MedLine, Lilacs, and Scielo. The search was performed in May 2021, afterreading the articles and their references. Theresults showed that drug interactions occur through the co-administrationof different compounds. In this context, drugs can suffer pharmaceuticalinteractions due to different physical-chemical processes, as well as afteradministration, interfering in the mechanisms of absorption, distribution,metabolism, and elimination of pharmacokinetics or pharmacodynamics, withchanges in the pharmacological effect. Such mechanisms can cause undesirableoutcomes, such as increased toxicity or impairment of therapeutic effect, or beused as a strategy for beneficial interactions to increase the pharmacologicaleffect or reduce toxicity. Given the clinical impacts that may occur due todrug interactions, knowledge about the different mechanisms involved in druginteractions is essential.