Glutamate Antagonist

Amantadine (Symmetrel)

This drug works in a different way from those already discussed. It does several things, but its main beneficial effect may be to promote the release of dopamine and to allow it to stay longer at its site of action.

Amantadine can be prescribed alone, but can also be taken in combination with other anti-parkinsonian drugs. Amantadine is available in capsules and as a syrup.

Relatively few newly diagnosed people with Parkinson's are prescribed amantadine.

Advantages

It has relatively few side effects. In some patients it reduces drug-induced dyskinesias without worsening the Parkinsonian symptoms. It may have a stimulatory effect and can help some people with tiredness.

Disadvantages

It usually has only a mild effect, helps only a minority of people and its effectiveness may be short-lived. It may cause swelling of the ankles or a mottled appearance on the skin of the lower leg, as well as causing confusion.