Rifampicin kinetics in undernutrition.

Rifampicin 10 mg/kg was administered as a single dose to eight undernourished subjects, 10 well nourished subjects and 10 undernourished patients on continuous antituberculosis therapy as a single dose. The area under plasma time concentration (AUC0----infinity) and the peak concentration were significantly reduced in both the undernourished groups. The apparent oral and renal clearances were increased in both the undernourished groups. The (AUC0----infinity) was reduced in undernourished due to reduced absorption and/or changes in total body clearance or disposition. The plasma protein binding of the drug was significantly reduced in the undernourished resulting in increased free drug concentration. This might be sufficient to ensure adequate therapeutic efficacy. Therefore alteration in dosage regimes are not necessary in the undernourished.