• A psychiatric disorder or a history of substance abuse
• Congestive heart failure (CHF)
• Glaucoma
• Low blood pressure (hypotension)
• Swelling in the hands, feet, or ankles
• Seizures or epilepsy
• Liver disease, such as liver failure, cirrhosis, or hepatitis
• Kidney disease, including kidney failure (renal failure)
• Any allergies, including allergies to foods, dyes, or preservatives.
   

• Pregnant or thinking of becoming pregnant
• Breastfeeding.
   

• An amantadine overdose can be dangerous. Deaths have occurred from both intentional and unintentional overdoses.
   
• People have attempted suicide while taking the drug. This may be more likely to occur in people who have a psychiatric disorder or a history of substance abuse. It may also be related to some of the unusual amantadine side effects, such as agitation, hallucinations, depression, or anxiety.
   
• Amantadine may make congestive heart failure (CHF) worse or may actually cause it. Check with your healthcare provider before taking the drug if you have CHF or swelling in the hands, feet, or ankles (as this can be a sign of CHF).
   
• The medication may worsen untreated acute angle-closure glaucoma (an eye condition).
   
• People with Parkinson's disease should not suddenly stop taking amantadine, as serious problems could occur.
   
• The medication may increase the risk of seizures in people who have epilepsy or seizure disorders. If you have either of these conditions, check with your healthcare provider before taking amantadine.
   
• Amantadine can cause a life-threatening condition called neuroleptic malignant syndrome (NMS). Some symptoms of NMS include:

• A high fever
• Stiff muscles
• Confusion
• Irregular pulse or blood pressure
• A fast heart rate (tachycardia)
• Sweating
• An irregular heart rhythm (arrhythmia).

Tell your healthcare provider right away if you think you might have NMS.

• If you have kidney or liver problems, your body may not handle amantadine as well as it should. You may need a lower amantadine dosage and, in some cases, the drug may not be recommended.
   
• Do not drive or operate heavy machinery until you know exactly how amantadine affects you.
   
• Amantadine can interact with a few different medications (see Drug Interactions With Amantadine).
   
• Amantadine is considered a pregnancy Category C medication. This means that it may not be safe for use during pregnancy, although the full risks are not known (see Symmetrel and Pregnancy).
   
• Amantadine passes through breast milk in humans. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Symmetrel and Breastfeeding).