[Changes of isoniazid concentrations in guinea pig blood and organs after various routes of drug administration].

Isoniazid concentrations were measured in the serum, liver, and lungs of the animals 1, 3, 6, and 24 hours after administration of isoniazid in a dose of 10 mg/kg via various routes (orally, intramuscularly, and lymphotropically--into the pretracheal cellular space) guinea-pig blood and organs in the experiment on 36 guinea-pigs. Within the first 1-3 hours after intramuscular injection of isoniazid, its concentrations in the serum and lungs were higher than those with other routes of administration. With lymphotropic and oral routes, the levels of the drug were very similar in all the studied media in the first 6 hours, but later its hepatic accumulation after lymphotropic administration proved to be considerably lower than via other routes. The lymphotropic injection of isoniazid provides its therapeutic concentrations in the blood and in the lung and simultaneously creates prerequisites for reducing the incidence and severity of hepatotoxic adverse reactions.