Purpose: Drug interactions and toxicities associated with the antiviral management of cytomegalovirus (CMV) infection are described.
Summary: The use of current antiviral treatments for CMV in patients undergoing solid organ or hematopoietic stem cell transplantation is categorically characterized by high-toxicity profiles and drug-drug interactions. The consequences of hematologic toxicities may be manifested clinically in several ways, including increased rates of infections and bleeding, more pronounced bone marrow suppression, and the development of anemia. Moreover, patients undergoing solid organ or stem cell transplantation have difficulty tolerating the nephrotoxic effects of current treatments, because their renal function is often already compromised by infection, sepsis, or the administration of other commonly used nephrotoxic drugs. Patients undergoing transplantation have an especially high risk of drug interactions, because multiple drugs are often administered to prevent allograft rejection, to treat or prevent infection, to control pain, and to treat a number of possible comorbid conditions. Commonly used antiviral agents for the management of CMV infection include cidofovir, CMV i.v. immunoglobulin, foscarnet, ganciclovir, and valganciclovir. Drug interactions associated with the use of ganciclovir and foscarnet sodium are numerous and potentially dangerous. At this time, such toxicities are managed by dosage adjustments, temporary discontinuations of medications, and careful monitoring of the patient.
Conclusion: Clinically important drug-drug interactions can occur in immunocompromised transplant recipients who are treated for CMV infection. Because of the high toxicity and narrow therapeutic range of the antiviral medications available for CMV management, patients should be carefully monitored for any potential adverse effects from such interactions.