Rifampicin (RFP) is one of the first-line drugs in the treatment of tuberculosis. Worldwide, the recommended administration of RFP is before breakfast, however it is commonly administered after the meal in Japan. It is known that the absorption of RFP is affected by a meal. Therefore, the effects of meal on the pharmacokinetics of rifampicin were studied in patients with tuberculosis.
Ten male patients participated in this study. Five of the ten patients were given three capsules (450mg of RFP) 30 minutes before breakfast. The other five patients were given the same dose of RFP 30 minutes after breakfast. The mean age and weight were 54.6±3.3 years and 53.9±2.7kg in the group before meal and in the after the meal group, 49.8±8.4 years and 53.8±5.0kg, respectively. All the data were expressed as mean±S.D. Blood samples were taken at 0, 2, 4 and 6 hours after capsule administration. RFP concentra tions in serum were analyzed by reversed-phase high performance liquid chromatography and the relevant pharmacokinetic parameters were calculated. Group means were compared by use of nonparametric statis tics.
In the group before meal, the peak concentration (Cmax) was significantly higher than that in the group after meal (9.32±0.88μg/mL versus 5.76 ± 1.04 μg/mL, p<0.05) and the AUC was also significantly higher than that in the group after meal (35.83±3.29μg/hr/mL versus 18.63±4.35μg/hr/mL, p<0.05). These results suggest that RFP should be taken 30 minutes before the meal.
