Interactions between zyloprim(allopurinol) and Cyclophosphamide lyophilized (cyclophosphamide)
allopurinol and cyclophosphamide (Moderate Drug-Drug)
MONITOR: Allopurinol may enhance the myelosuppressive side effects of cyclophosphamide. Allopurinol does not appear to increase the serum half-life of cyclophosphamide, but has been shown to cause a 38% average increase in the plasma concentration of cyclophosphamide metabolites. It is suspected that the mechanism is either induction of hepatic metabolism of the parent cyclophosphamide compound or decreased renal clearance of cyclophosphamide metabolites. Clinically, this interaction could increase the risk of bleeding and infection.
MANAGEMENT: If these drugs must be given together, frequent monitoring for myelosuppression, hemorrhagic cystitis, cardiotoxicity, interstitial pneumonitis, and bleeding is recommended.
