Pharmacokinetics of Amantadine Hydrochloride in Subjects with Normal and Impaired Renal Function

Abstract

Amantadine is useful for the prevention and treatment of influenza A and for the treatment of Parkinson''s disease and drug-induced extrapyramidal disorders. The pharmacokinetics of amantadine in patients with impaired or negligible renal function was compared to that in normal subjects. The half-life of elimination in subjects with normal renal functions was 11.8 .+-. 2.1 h (range, 9.7-14.5 h). Eight patients with various degrees of renal insufficiency (creatinine clearance from 43.1 to 5.9 ml/min .cntdot. 1.73 m) had half-lives of elimination from 18.5 h to 33.8 days. Ten patients on thrice-weekly hemodialysis. Assuming complete bioavailability of the drug, less than 5% of the dose was removed by each 4 h hemodialysis. The mean half-life of elimination during chronic hemodialysis was 8.3 days (range, 7.0-10.3). Guidelines are presented for use of amantadine in patients with impaired renal function, including those on maintenance hemodialysis.