Colchicine kinetics in patients with familial Mediterranean fever

Serum colchicine levels were determined by radioimmunoassay after a 1‐mg bolus injected intravenously in 4 patients with familial Mediterranean fever and in 6 normal subjects. Mean elimination half‐life (t½) (±SEM) was 157 ± 20 min in the patients and 65 ± 15 min in the normal subjects (p < 0.005). Total clearance was 239 ± 50 ml/min in the patients and 601 ± 155 ml/min in the normal subjects (p < 0.05). Volume of distribution (Vd_area) was 76 ± 16 and 49 ± 9 l and did not differ significantly. In 8 patients receiving colchicine prophylactically with good clinical response, serum colchicine ranged from 0.3 to 2.4 ng/ml after daily doses of 1 mg orally. In 2 responding patients 2‐mg doses orally induced levels from 4 to 10 ng/ml, and in one (a nonresponder) a 3‐mg dose induced levels of 7.5 to 13 ng/ml. Of 3 patients receiving 2 mg daily with unsatisfactory clinical responses, serum levels were not detectable in one and in the low range of 1.5 to 5.4 ng/ml in the others. It is suggested that lack of response to colchicine orally in some nonresponders could result from inadequate absorption or altered disposition of colchicine. Clinical Pharmacology and Therapeutics (1980) 28, 82–87; doi: