Amandatine is useful in the treatment of Parkinson's syndrome and in the short-term management of drug-induced extrapyramidal symptoms.In Parkinson's syndrome, amantadine has been used alone and in combination with anticholinergic antiparkinson drugs and with levodopa. The final therapeutic benefit seen with amantadine is significantly less than that seen with levodopa. The maximal therapeutic benefit to be obtained with amantadine is usually seen within 1 week. However, initial benefits may diminish with continued dosing.
Amantadine is useful as an adjunct in patients who do not tolerate optimal doses of levodopa alone or in combined therapy with a decarboxylase inhibitor. In these patients, the addition of amantadine may result in better control of Parkinson's syndrome and may help to smooth out fluctuations in performance.
The comparative efficacy of amantadine and anticholinergic antiparkinson drugs has not yet been established. When amantadine or anticholinergic antiparkinson drugs are each used with marginal benefit, concomitant use may permit the same degree of control, often with a lower dose of the anticholinergic medication.
Amantadine is effective in reducing severity or abolishing drug-induced extrapyramidal reactions including parkinsonism syndrome, dystonia and akathisia. It is not effective in the management of tardive dyskinesia.
Although anticholinergic-type side effects have been noted when used in patients with drug-induced extrapyramidal reactions, there appears to be a lower incidence of these side effects than that observed with anticholinergic antiparkinson drugs.
Antiparkinsonian agents should not usually be used prophylactically during neuroleptic administration. However, they may be given when needed to suppress extrapyramidal symptoms. Therefore, amantadine may be used in the management of extrapyramidal symptoms which cannot be controlled by reduction of neuroleptic dosage, but should be discontinued as soon as it is no longer required. Amantadine should be withdrawn after a period of time to determine whether there is recrudescence of extrapyramidal symptoms.
