Tetracycline kinetics in undernourished subjects.

The pharmacokinetics of tetracycline were studied in eight normal healthy adult male volunteers and six undernourished adult males, ages 25-40 years, after an intravenous dose of 10 mg/kg body wt. The post-intravenous tetracycline time curve was found to decline in a biphasic manner in both well-nourished and undernourished subjects. However, significant differences were observed in alpha and beta phase with significant alterations in microscopic rate constants and apparent volume of distribution. The kinetic constants suggested a rapid distribution with a faster rate of transfer of drug between compartments followed by a significant increase in total body clearance in undernourished subjects. The apparent volume of distribution was significantly reduced. It is concluded that due to alterations in kinetics undernourished subjects may require altered dosage regimens to maintain tetracycline concentrations above the recommended minimum inhibitory concentration in both plasma/tissue for effective therapy.