Important drug interactions in patients with rheumatic disorders: interactions of glucocorticoids, immunosuppressants and antimalarial drugs

Despite the fact that biological treatments are very promising, classical immunosuppressants, antimalarial drugs and glucocorticosteroids are still very important and widely used in practice. Although drug interactions can have fatal consequences, few studies have reviewed drug interactions of these classical drugs used in rheumatology, and very few guidelines are available on this subject. Therefore, this report summarizes important interactions of immunosuppressants, antimalarial drugs and glucocorticosteroids with drugs commonly used in internal medicine. In the present study, more than 300 interactions were retrieved from the Micromedex ? database. The selection was reduced to the interactions rated as moderate, major or contraindicated. The selected interactions were further checked against PubMed ?, MEDLINE ?, InfoPharm Compendium of Drug Interactions and Summaries of Product Characteristics. For each interaction, its nature, mechanism, onset and clinical severity were indicated, documentation quality was rated and recommendations for clinical practice were formulated. Twenty significant interactions that we rated as moderate, severe and very severe were identified. Interacting drugs were warfarin, fluoroquinolones, azole antifungals, co-trimoxazole, proton pump inhibitors, amiodarone, cholestyramine, activated carbon, allopurinol, angiotensin-converting enzyme inhibitors, statins, digoxin, iron, aluminium and magnesium salts, and hepatotoxic and nephrotoxic agents.