If there is no improvement in a few days, or if medication appears less effective after a few weeks, discuss with a physician.Seek medical attention immediately if it is suspected that an overdose of medication has been taken.Careful observation is required when amantadine hydrochloride is administered concurrently with central nervous system stimulants.Agents with anticholinergic properties may potentiate the anticholinergic-like side effects of amantadine.Coadministration of thioridazine has been reported to worsen the tremor in elderly patients with Parkinson's disease, however, it is not known if other phenothiazines produce a similar response. They are supplied as follows:Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature]. When amantadine hydrochloride tablets or anticholinergic antiparkinson drugs are each used with marginal benefit, concomitant use may produce additional benefit.When amantadine hydrochloride tablets and levodopa are initiated concurrently, the patient can exhibit rapid therapeutic benefits. There are no well-controlled clinical studies demonstrating that treatment with amantadine hydrochloride tablets will avoid the development of influenza A virus pneumonitis or other complications in high risk patients. In a three litter, non-GLP, reproduction study in rats, amantadine hydrochloride at a dose of 32 mg/kg/day (equal to the maximum recommended human dose on a mg/mThe effect of amantadine on embryofetal and peri-postnatal development has not been adequately tested, that is, in studies conducted under Good Laboratory Practice (GLP) and according to current recommended methodology. May 26, 2020 After one to several weeks at 100 mg once daily, the dose may be increased to 100 mg twice daily, if necessary. All options are taken once daily in the morning.

Acetylamantadine was not detected in the plasma of the remaining seven volunteers.

Whether these changes are due to decline in renal function or other age related factors is not known.In a study of young healthy subjects (n=20), mean renal clearance of amantadine, normalized for body mass index, was 1.5 fold higher in males compared to females (p<0.032).Compared with otherwise healthy adult individuals, the clearance of amantadine is significantly reduced in adult patients with renal insufficiency. Central nervous system effects that have been reported include insomnia, anxiety, agitation, aggressive behavior, hypertonia, hyperkinesia, ataxia, gait abnormality, tremor, confusion, disorientation, depersonalization, fear, delirium, hallucinations, psychotic reactions, lethargy, somnolence and coma.

Following the administration of amantadine 100 mg as a single dose, the mean ± SD red blood cell to plasma ratio ranged from 2.7 ± 0.5 in 6 healthy subjects to 1.4 ± 0.2 in 8 patients with renal insufficiency.The apparent oral plasma clearance of amantadine is reduced and the plasma half-life and plasma concentrations are increased in healthy elderly individuals age 60 and older. Following vaccination during an influenza A outbreak, amantadine hydrochloride tablets prophylaxis should be considered for the 2 to 4 week time period required to develop an antibody response.Amantadine hydrochloride tablets are also indicated in the treatment of uncomplicated respiratory tract illness caused by influenza A virus strains especially when administered early in the course of illness.

Because some patients have attempted suicide by overdosing with amantadine, prescriptions should be written for the smallest quantity consistent with good patient management.Acute toxicity may be attributable to the anticholinergic effects of amantadine.