The pharmacokinetic evaluation of tranexamic acid following intravenous (i. v.) and intramuscular (i. m.) administrations to three volunteers, and oral administration (p. o.) to ten volunteers was made. The results obtained from various admini stration routes are discussed.
The maximum plasma levels of tranexamic acid were 21.2 μg/ml at 0.5 hour after i. m. administration (500 mg dose), and 6.0 μg/ml at 2 hours after oral admini stration (500 mg dose), and the plasma level at 15 minutes after i. v. administration (1000 mg dose) was 60 μg/ml. The biological half-lives for i. v., i, m. and p. o. were 1.9, 2.0 and 3.3 hours, respectively. Urinary excretion of tranexamic acid during 24 hours after administration was 80% of the dose for i. v., 76% for i. m. and 40-70% for p. o. This suggests that tranexamic acid is absorbed slowly from the intestine and is mainly eliminated from the kidney.