Amantadine (HCl)

Amantadine is primarily excreted unchanged in the urine, patients with renal impairment should receive lower doses. Renal function should be monitored closely and the dose adjusted accordingly. The elderly require lower dosages, because delayed clearance of amantadine in the elderly can increase toxic effects. Peripheral edema and congestive heart failure can be precipitated by amantadine; patients at risk should be treated with caution. Amantadine can increase seizure activity in patients with a seizure disorder. Patients with a history of seizures should be monitored closely when amantadine is initiated. Patients with eczema should receive amantadine with caution. Recurrent eczema or rash can be aggravated during treatment. The psychotic effects may be dose-related, but patients with pre-existing psychoses should be treated with caution. Abrupt withdrawal of amantadine should be avoided in patients with Parkinsons disease since this may precipitate symptoms of increased rigidity, confusion, urinary retention, or bulbar palsy. Amantadine is classified as a pregnancy category C drug. Use during pregnancy should be avoided unless the potential benefits outweigh the possible risks to the fetus.