The pharmacokinetics of ketoprofen were evaluated in 29 patients suffering from acute renal colic following a single intravenous administration as a bolus or short infusion (1.5 and 2 hours), and after a loading dose and a 24-hour infusion. Serum concentrations of ketoprofen were measured by high pressure liquid chromatography. The mean (± SD) values of clinical parameters were as follows: distribution half-life = 0.34 ± 0.19h; elimination half-life = 2.05 ± 0.58h; kel= 0.968 ± 0.282h−1; k21= 0.943 ± 0.425 h−1; k12= 1.004 ± 0.708 h−1; volume of central compartment = 5.58 ± 1.67L; volume of tissue compartment = 5.14 ± 2.12L; plasma clearance = 5.10 ± 1.14L/h. These results concur with previously published data obtained after oral or intramuscular administration.According to clinical observations, administration of a ketoprofen bolus suppressed pain within 5 to 30 minutes; the administration of a loading dose and a 24-hour infusion is almost never followed by a recurrence of pain, and this regimen was proposed as the dosage schedule of ketoprofen to treat renal colic.