Interactions of anti-infectives: a review

Drug interactions can be beneficial and valuable, but their consequences are usually adverse/undesirable, thus compromising the efficacy of drugs and enhancing their toxicity. Interactions can be divided into pharmaceutical incompatibilities, and pharmacokinetic and pharmacodynamic interactions. Unexpected drug responses can result from drug-excipient incompatibilities or erroneous technological processes. Pharmacokinetic interactions can affect the processes of drug absorption, distribution, metabolization and excretion. Pharmacodynamic interactions occur when the effects of one drug are changed by the presence of another drug at its site of action; such interactions are classified as synergistic and antagonistic. The clinically most relevant drug interactions following this classification and regarding the use of anti-infectives are reviewed. Knowledge, research and discussion of drug interactions will assist in giving the patient optimal care.