Probenecid and Colchicine

INDICATIONS AND USAGE For the treatment of chronic gouty arthritis when complicated by frequent, recurrent acute attacks of gout.

WARNINGS Exacerbation of gout following therapy with probenecid and colchicine may occur; in such cases additional colchicine or other appropriate therapy is advisable. Probenecid increases plasma concentrations of methotrexate in both animals and humans. In animal studies, increased methotrexate toxicity has been reported. If probenecid and colchicine is given with methotrexate, the dosage of methotrexate should be reduced and serum levels may need to be monitored. In patients on probenecid and colchicine the use of salicylates in either small or large doses is contraindicated because it antagonizes the uricosuric action of probenecid. The biphasic action of salicylates in the renal tubules accounts for the so-called "paradoxical effect" of uricosuric agents. In patients on probenecid and colchicine who require a mild analgesic agent the use of acetaminophen rather than small doses of salicylates would be preferred. Rarely, severe allergic reactions and anaphylaxis have been reported with the use of probenecid and colchicine. Most of these have been reported to occur within several hours after readministration following prior usage of the drug. The appearance of hypersensitivity reactions requires cessation of therapy with probenecid and colchicine. Colchicine has been reported to adversely affect spermatogenesis in animals. Reversible azoospermia has been reported in one patient.