Common uses

Symmetrel is used for preventing and treating certain types of flu. It is used to treat Parkinson disease and uncontrolled muscle movements caused by some medicines. It may also be used for other conditions as determined by your doctor.
Symmetrel is an antiparkinson and antiviral agent. How Symmetrel works against the flu is not known. It may block reproduction of the virus and decrease the ability of the virus to get into the cells. How Symmetrel works against Parkinson disease is not known. It may increase a certain chemical in the brain.

Before using

Some medical conditions may interact with Symmetrel . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have a history of heart problems (eg, congestive heart failure), swelling of your hands or feet, mental or mood problems, suicidal thoughts or actions, seizures, glaucoma, low blood pressure, dizziness when you stand or sit up, an eczema-like rash, or kidney or liver problems
• if you have received an intranasal flu vaccine within the last 14 days

Directions

Use Symmetrel as directed by your doctor. Check the label on the medicine for exact dosing instructions.
• Take Symmetrel by mouth with or without food.
• If you are using Symmetrel for the flu, take it for the full course of treatment. Keep using Symmetrel even if you feel better in a few days. This will help clear up your infection completely.
• If you miss a dose of Symmetrel , take it as soon as possible. If it is almost time for your next dose, skip the missed dose. Go back to your regular dosing schedule. Do not take 2 doses at once.

Cautions

Before taking Symmetrel, tell your doctor or pharmacist if you have any medical conditions, especially if you have allergies to medicines, foods, or other substances, if you are allergic to any ingredient in Symmetrel, if you have a history of heart problems (eg, congestive heart failure), swelling of your hands or feet, mental or mood problems, suicidal thoughts or actions, seizures, glaucoma, low blood pressure, dizziness when you stand or sit up, an eczema–like rash, or kidney or liver problems, if you are pregnant, planning to become pregnant or are breast–feeding. If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using this medicine while you are pregnant. Symmetrel is found in breast milk. Do not breast–feed while taking Symmetrel. Some medicines may interact with Symmetrel. Therefore tell your doctor of all prescription or nonprescription medicine, herbal preparation, or dietary supplement that you are taking. Do not take Symmetrel if you have uncontrolled narrow–angle glaucoma. Do not become overheated in hot weather or while you are being active, heatstroke may occur. Symmetrel only works against certain types of the flu, it does not treat other viral infections (eg, the common cold). If you are taking Symmetrel for Parkinson disease, increase physical activity slowly as your symptoms improve. Do not suddenly stop taking Symmetrel without first checking with your doctor. Your dose may need to be lowered slowly to avoid side effects. Neuroleptic malignant syndrome (NMS) is a possibly fatal syndrome that can be caused by Symmetrel. Symptoms may include fever, stiff muscles, confusion, abnormal thinking, fast or irregular heartbeat, and sweating. Elderly patients may be more sensitive to the effects of Symmetrel and might require a lower dose and/or special monitoring during treatment. Use Symmetrel with extreme caution in children younger than 1 year old, safety and effectiveness in these children have not been confirmed.

Possible side effects

Amantadine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
• blurred vision
• dizziness
• lightheadedness
• faintness
• trouble sleeping
If you experience any of the following side effects, call your doctor immediately:
• depression or anxiety
• swelling of the hands, legs, or feet
• difficulty urinating
• shortness of breath
• rash

If you take too much

If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms may include aggression; chest pain; confusion; decreased urination; fast or irregular heartbeat; fever; hallucinations; loss of consciousness; mental or mood changes; seizures; severe drowsiness; severe or persistent headache or dizziness; tremor; trouble breathing; trouble walking. Overdose of Symmetrel may cause death.

Additional information

Symmetrel may cause drowsiness, dizziness, or blurred vision. These effects may worsen if Symmetrel is taken with alcohol or certain other medications. Use Symmetrel with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to this drug. If your symptoms do not improve or if they worsen, contact your doctor. Symmetrel should be used only by the patient for whom it has been prescribed. Do not take less or more or take it more often than prescribed by your doctor.

Drug interactions

Tell your health care provider if you are taking any other medicines, especially any of the following:
• Thioridazine because tremors may be worsened in Parkinson patients
• Anticholinergics (eg, scopolamine), hydrochlorothiazide, quinidine, quinine, stimulants (eg, caffeine, methylphenidate, pseudoephedrine), or triamterene because they may increase the risk of Symmetrel 's side effects
This may not be a complete list of all interactions that may occur. Ask your health care provider if Symmetrel may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.