title: Effects of chronic amantadine hydrochloride ingestion on its and acetaminophen pharmacokinetics in young adults.
abstract: The authors studied the effect of chronic amantadine ingestion on its own disposition and that of acetaminophen in five healthy young adults. The half-life of amantadine after 42 days ingestion was 15.1 +/- 2.3 hours and was not different from 14.8 +/- 4.4 hours after an acute ingestion (mean +/- SD). However, chronic amantadine ingestion was associated with an increased apparent volume of distribution for acetaminophen, 1.1 +/- 0.1 L/kg compared with 0.9 +/- 0.1 L/kg, when the two drugs were concurrently ingested after a 2-week washout period. This difference in kinetic distribution was not reflected in terminal acetaminophen half-life, 149 +/- 54 versus 151 +/- 55 minutes for chronic and acute amantadine ingestion, respectively. Plasma acetaminophen clearance with chronic amantadine ingestion (5.8 +/- 2.6 mL/min/kg) was not different from that determined after acute coingestion of both drugs (4.3 +/- 1.1 mL/min/kg). Thus, no change in recommended dose is necessary when these two drugs are coingested.
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: F Y
authors.initials: FY
authors.lastname: Aoki
authors.forename: D S
authors.initials: DS
authors.lastname: Sitar
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000284:Administration, Oral; D000328:Adult; D000547:Amantadine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D013997:Time Factors
chemical_list: D000082:Acetaminophen; D000547:Amantadine