What is the most important information I should know about Symmetrel?

• Do not stop taking Symmetrel suddenly if you are using it to treat Parkinson's disease. Doing so may cause your condition to suddenly become much worse.
• If you are taking Symmetrel to treat influenza A, take all of the medication that has been prescribed for you even if you begin to feel better. Your symptoms may start to improve before the infection is completely treated.

What is Symmetrel?

• Symmetrel is an antiviral medication. It blocks the actions of viruses in your body.
• Symmetrel is used to treat and to prevent influenza A (a viral infection). There may be some flu seasons during which Symmetrel is not recommended because certain flu strains may be resistant to this drug.
• Symmetrel is also used to treat Parkinson's disease and “parkinson-like” symptoms such as stiffness and shaking that may be caused by the use of certain drugs. How Symmetrel works in these conditions is unknown.
• Symmetrel may also be used for purposes other than those listed in this medication guide.

Who should not take Symmetrel?

• Before taking Symmetrel, tell your doctor if you have
  • epilepsy or any other seizure disorder;
  • congestive heart failure or an accumulation of fluid (swelling) in your arms, legs, hands, or feet;
  • any type of kidney disease;
  • any type of liver disease; or
  • a chronic rash such as eczema.
• You may need a lower dose or special monitoring during treatment if you have any of the conditions listed above.
• Symmetrel is in the FDA pregnancy category C. This means that it is not known whether it will harm an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant.
• Symmetrel passes into breast milk. It is not known whether it will harm a nursing baby. Do not take this medication without first talking to your doctor if you are breast-feeding a baby.

How should I take Symmetrel?

• Take Symmetrel exactly as directed by your doctor. If you do not understand the directions on your prescription bottle, ask your pharmacist, nurse, or doctor to explain them to you.
• Take each dose with a full glass of water.
• To ensure that you get a correct dose, measure the liquid form of Symmetrel with a special dose-measuring spoon or cup, not with a regular tablespoon. If you do not have a dose-measuring device, ask your pharmacist for one.
• If you are taking Symmetrel to treat influenza A, take all of the medication that has been prescribed for you even if you begin to feel better. Your symptoms may start to improve before the infection is completely treated.
• Store Symmetrel at room temperature away from moisture and heat.

What happens if I miss a dose?

• Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the dose you missed and take only your next regularly scheduled dose. Do not take a double dose of this medication.

What happens if I overdose?

• Seek emergency medical attention.
• Symptoms of an Symmetrel overdose include an increased heart rate; high blood pressure (blurred vision, severe headache); anxiety; difficulty breathing; insomnia; aggression; tremor; confusion; hallucinations; paranoia; coma; seizures; and even death.

What should I avoid while taking Symmetrel?

• Use caution when driving, operating machinery, or performing other hazardous activities. Symmetrel may cause dizziness. If you experience dizziness, avoid these activities.

What are the possible side effects of Symmetrel?

• If you experience any of the following serious side effects, stop taking Symmetrel and seek emergency medical attention:
  • an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
  • congestive heart failure (swelling in your lower legs or feet, difficulty breathing, fatigue);
  • severe stiffness or involuntary movements of your arms or legs; or
  • confusion after discontinuing Symmetrel or after a dose reduction.
• Other, less serious side effects are more likely to occur. Continue to take Symmetrel and talk to your doctor if you experience
  • dizziness, lightheadedness, drowsiness, or a headache;
  • insomnia;
  • nausea or decreased appetite;
  • dry mouth or constipation; or
  • depression, anxiety, or confusion.
• Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What other drugs will affect Symmetrel?

• Other drugs that stimulate your central nervous system, such as caffeine, diet pills, and decongestants, may increase the side effects from Symmetrel. Do not take any prescription or over-the-counter medicines for weight loss, for colds, for allergies, or to help you stay awake without first talking to your doctor or pharmacist.
• Tell your doctor if you are taking a diuretic (water pill). You may need special monitoring during your therapy.
• Phenothiazines used to treat emotional disorders, such as chlorpromazine (Thorazine) and thioridazine (Mellaril), may increase tremor during Symmetrel therapy. Tell your doctor about any medicines you are taking for emotional conditions.
• Drugs other than those listed here may also interact with Symmetrel. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.