Drug Interactions between clozapine and eflornithine

Consumer information for this interaction is not currently available.

MONITOR CLOSELY: Coadministration of clozapine with other agents that can cause granulocytopenia, neutropenia, or agranulocytosis (severe neutropenia) may increase the risk and/or severity of hematologic toxicity. Clozapine alone is associated with a significant risk of severe neutropenia, defined as an absolute neutrophil count (ANC) of less than 500/µL (0.5 x 10^9/L), and its development appears independent of dose and treatment duration. The exact mechanism by which clozapine leads to neutropenia is unknown; however, several test systems using animal bone marrow cells suggest that clozapine has a suppressant effect on cell division. Some authorities estimate the incidence of neutropenia and severe neutropenia from clozapine therapy at 3% and 0.7%, respectively, with more severe cases occurring during the first 18 to 26 weeks of treatment. Fatal cases of clozapine-induced neutropenia have been rarely reported, and the majority of these cases occurred prior to the recognition of the risk of clozapine-induced neutropenia and the need for routine blood monitoring during clozapine therapy.

MANAGEMENT: If clozapine is used concurrently with an agent known to cause neutropenia (e.g., antineoplastic drugs, some anticonvulsant and antirheumatic medications, albendazole, chloramphenicol, colchicine, dapsone, interferons, linezolid, pentamidine, procainamide, and zidovudine), consider monitoring patients more closely than the standard guidelines suggested in the product labeling. If a patient is receiving concomitant chemotherapy, the treating oncologist should be consulted. Some authorities consider this combination to be contraindicated.