Antibacterial macrolides: a drug class with a complex pharmacological profile.

Macrolides are widely used antibacterial agents. Although generally well tolerated, they have a number of important additional pharmacological effects, which can sometimes result in significant adverse reactions. This review focuses on three of these side effects: the prokinetic action associated with stimulation of motilin receptors, the proarrhythmic effect due to prolongation of the QT interval of the electrocardiogram and the potential for drug interactions due to inhibition of drug metabolising enzymes. For macrolides that have obtained marketing authorisation in Italy, United Kingdom or United States of America, we also considered whether these actions are properly reported in the approved summaries of the product characteristics and tried to provide strategies to identify patients at risk of significant side effects when macrolides are administered.