Clinically significant drug interactions with new immunosuppressive agents

Area of Science:

• Pharmacology
• Immunology
• Clinical Pharmacy

Background:

• New immunosuppressive agents including tacrolimus (FK506), mycophenolate mofetil, sirolimus (rapamycin), gusperimus, and monoclonal antibodies are increasingly used in clinical practice.
• Some of these agents are approved, while others are in clinical trials, necessitating an understanding of their potential interactions.

Purpose of the Study:

• To provide a comprehensive overview of adverse drug interactions involving novel immunosuppressive agents.
• To highlight potential pharmacokinetic and pharmacodynamic interactions and their clinical implications.

Main Methods:

• Literature review and synthesis of existing data on drug interactions with new immunosuppressants.
• Analysis of reported interactions concerning tacrolimus, mycophenolate mofetil, sirolimus, gusperimus, and monoclonal antibodies.

Main Results:

• Tacrolimus interactions: Increased nephrotoxicity with NSAIDs; altered blood concentrations with antibiotics (erythromycin, clarithromycin), antifungals (clotrimazole, fluconazole, ketoconazole), danazol, and rifampicin; potential inhibition of coadministered drug metabolism.
• Mycophenolate mofetil interactions: Reduced bioavailability with antacids and cholestyramine.
• Other interactions: Enhanced bone marrow suppression with concomitant myelosuppressive drugs; increased CNS adverse effects with indomethacin and muromonab CD3 (OKT3); potential for increased blood concentrations between sirolimus and cyclosporin.

Conclusions:

• Adverse drug interactions are a significant concern with new immunosuppressive agents, impacting efficacy and safety.
• Clinicians must be aware of these interactions to optimize patient care and minimize risks such as nephrotoxicity and myelosuppression.
• Further research into drug interactions with these agents is warranted to ensure safe and effective immunosuppression protocols.