Investigation of the interaction between argatroban and acetaminophen, lidocaine, or digoxin

The potential pharmacokinetic interactions between argatroban and acetaminophen, lidocaine, or digoxin were examined. Three randomized crossover studies were conducted. In the first study, 11 subjects completed three sessions (with a five-day washout period between sessions), receiving two 500-mg acetaminophen caplets at 0, 6, 12, 18, and 24 hours; i.v. argatroban 1.5 micrograms/kg/min from hours 12 to 30; or a combination of both. In the second study, 12 subjects completed three sessions (with a five-day washout period between sessions), receiving lidocaine hydrochloride injection 2 mg/kg/hr for 16 hours (after receiving a loading dose of 1.5 mg/kg over 10 minutes), i.v. argatroban 1.5 micrograms/kg/min for 16 hours, or a combination of both. In the third study, 12 subjects completed two sessions (with a seven-day washout period between sessions), receiving oral digoxin 0.375 mg/day for 15 days and either i.v. placebo or argatroban 2 micrograms/kg/min on days 11 through 15. Primary pharmacokinetic values in each study included area under the drug concentration versus time curve and steady-state concentrations of argatroban and the concomitantly administered drug. Lack of a pharmacokinetic interaction (individually defined for each study) was demonstrated in each study. Argatroban, regardless of acetaminophen or lidocaine administration, prolonged activated partial thromboplastin time values approximately 1.6-1.8 times the baseline values. No deaths, unexpected adverse events, or clinically significant changes in safety laboratory values occurred. No pharmacokinetic interaction was detected between argatroban and acetaminophen, lidocaine, or digoxin. Argatroban is well tolerated during coadministration with these drugs. In practice, argatroban coadministered with these frequently prescribed drugs should require no dosage adjustments.