Probenecid and Colchicine

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.

ADVERSE REACTIONS The following adverse reactions have been observed and within each category are listed in order of decreasing severity. Probenecid Central Nervous System: headache, dizziness. Metabolic: precipitation of acute gouty arthritis. Gastrointestinal: hepatic necrosis, vomiting, nausea, anorexia, sore gums. Genitourinary: nephrotic syndrome, uric acid stones with or without hematuria, renal colic, costovertebral pain, urinary frequency. Hypersensitivity: anaphylaxis, fever, urticaria, pruritus. Hematologic: aplastic anemia, leukopenia, hemolytic anemia which in some patients could be related to genetic deficiency of glucose-6-phosphate dehydrogenase in red blood cells, anemia. Integumentary: dermatitis, alopecia, flushing. Colchicine Side effects due to colchicine appear to be a function of dosage. The possibility of increased colchicine toxicity in the presence of hepatic dysfunction should be considered. The appearance of any of the following symptoms may require reduction of dosage or discontinuance of the drug. Central Nervous System: peripheral neuritis. Musculoskeletal: muscular weakness. Gastrointestinal: nausea, vomiting, abdominal pain, or diarrhea may be particularly troublesome in the presence of peptic ulcer or spastic colon. Hypersensitivity: urticaria. Hematologic: aplastic anemia, agranulocytosis. Integumentary: dermatitis, purpura, alopecia. At toxic doses, colchicine may cause severe diarrhea, generalized vascular damage, and renal damage with hematuria and oliguria. To report SUSPECTED ADVERSE REACTIONS, contact Rising Pharma Holdings, Inc. at 1-844-874-7464 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .