Amantadine (Symmetrel) is an anti-influenza medication that has been discovered to cause less tremor in PD patients. It often provides immediate benefit for most PD symptoms and can reduce levodopa - induced dyskinesia. It is most commonly available as a capsule, but liquid and tablet formats are also available. The most frequent side effects include:

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• Nausea

• Dry Mouth

• Lightheadedness

• Insomnia

• Confusion

• Pedal edema

• Hallucinations

• Purple discoloration of skin

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Starting and stopping the drug instantly could cause serious withdrawal syndromes. The medication is also available in an extended-release format. These tablets should not be split, crushed, or chewed, unlike other medications. This drug is used most in combination with carbidopa/levodopa for "on/off" fluctuations.