Table 1: Recommended amantadine hydrochloride dosage by age and renal status
Renal status	Patient age, yr; dosage
	1–9*	10–64	>= 65
No recognized renal disease	5mg/kg once daily, or, divided, twice daily; total daily dose not to exceed 150 mg	200 mg once daily or, divided, twice daily†	100 mg once daily‡
Recognized renal disease; creatinine clearance,§ mL/min × 1.73m -2
>= 80	NA	100 mg twice daily	100 mg once daily
60–79	NA	Alternating daily doses of 200 and 100 mg	Alternating daily doses of 100 and 50 mg
40–59	NA	100 mg once daily	100 mg every 2 days
30–39	NA	200 mg twice weekly	100 mg twice weekly
20–29	NA	100 mg three times weekly	50 mg three times weekly
10–19	NA	Alternating weekly doses of 200 and 100 mg	Alternating weekly doses of 100 and 50 mg
*Use in children under 1 year of age has not been evaluated adequately. †Reduction of dosage to 100 mg/d is recommended for people with a seizure disorder because they may be at risk for more frequent seizures when the dosage is 200 mg/d. ‡The reduced dosage is recommended to minimize the risk of toxic effects because renal function generally declines with age and because side effects have been reported more frequently in elderly people. §Calculation of estimated creatinine clearance: Male:  CrCl mL/min =     (140 - age) × weight (kg)     ------------------------------     serum creatinine level (µmolL) × 0.81 Female: CrCl mL/min = 0.85 × CrCl (male) NA = not applicable. Adapted from Can Commun Dis Rep 1997;23(ACS-2):9 with permission of the Minister of Public Works and Government Services Canada.

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