Generic Symmetrel

Common use

Symmetrel is an antiviral medication which used to prevent or treat certain influenza infections. Symmetrel blocks the actions of viruses in your body. This drug is also used for treatment Parkinson's disease and "Parkinson-like" symptoms, including stiffness and shaking.



Dosage and direction

Take it orally with a full glass of water or food/milk. Swallow whole, do not crush it. Use Symmetrel at the same time each day for best result. The usual dosage of Symmetrel is 100 to 200 mg daily, it depends from your body weight. Also the recommended adult dose varies according to the condition being treated:

1.Treatment of Parkinson's disease:

the recommended adult dose is 100 mg once daily to start. After one to several weeks, it may increase to 100 mg twice daily.

2.Treatment and prevention of influenza A infections:

the recommended dose for adults and children 13 years of age and older is 200 mg daily. For children 9-12 years of age, the recommended dose is 100 mg taken twice daily. For children 1 to 12 years old, the dose is prescribed by the body weight of the child.

3.To prevent influenza A infections:

Symmentrel should be taken before or after contact with a infected person and continued for 10 days after contact with him.

Note: this instruction presented here just for review. It's very necessary to consult with your doctor before using. It help you to get best results.



Precautions

Suicide attempts and deaths have been reported in patients treated with Symmetrel. Suicide attempts and ideations have been reported in patents with and without a history of psychiatric illness. Symmetrel can exacerbate symptoms in patients with a history of psychiatric disorders or substance abuse. Patients with a history of epilepsy should be monitored closely, as well as patients with a history of congestive heart failure, peripheral edema, eczematoid rash, or renal impairment. Do not use in patients with untreated angle closure glaucoma. Patients should be closely observed upon discontinuation or dose reduction of Symmetrel, as some cases of Neuroleptic Malignant Syndrome (NMS) have been reported. NMS is a life-threatening syndrome characterized by fever, muscle rigidity, involuntary movements, altered consciousness, mental status changes and increased heart rate and blood pressure changes. Do not use alcohol during the treatment by Symmetrel. Symmetrel should not be used during pregnancy, becoming pregnant or lactating without doctor's advice. Do not use Symmetrel before breast-feeding without doctor's advice.



Contraindications

Symmetrel is not allowed to people who are hypersensitive to any components of this medicine. Contraindicated in case of individuals subject to convulsions or if your medical history include gastric ulceration, severe renal disease. Contraindicated in pregnancy.



Possible side effect

They may include all types of an allergic reaction. Also the most possible side effects include:

feeling short of breath, even with mild exertion;

swelling, rapid weight gain;

feeling depressed, agitated, or aggressive;

behavior changes, hallucinations, thoughts of hurting yourself;

urinating less than usual or not at all;

high fever, stiff muscles, confusion, sweating, fast or uneven heartbeats, rapid breathing, feeling like you might pass out;

restless muscle movements in your eyes, tongue, jaw, or neck; or

tremor (uncontrolled shaking).

Less serious include:

dizziness, drowsiness, headache;

sleep problems (insomnia), strange dreams;

feeling nervous;

nausea, diarrhea, constipation, loss of appetite;

dry mouth, dry nose; or

loss of balance or coordination.

If you experience one of them stop using Symmetrel and tell your doctor as soon as possible. Also consult with your doctor about any side effect that seems unusual.



Drug interaction

Symmetrel interact with the following drugs: atropine; dicyclomine; glycopyrrolate; hyoscyamine; mepenzolate; methscopolamine; propantheline; scopolamine. quinine; quinidine; a diuretic such as triamterene, hydrochlorothiazide, and others; or phenothiazines such as prochlorperazine, thioridazine, and others. Also note that interaction between two medications does not always mean that you must stop taking one of them. As usual it affects the the effect of drugs, so consult with your doctor about how it interactions are being managed or should be managed.



Missed dose

If you forgot to take your dose in time, please do it as soon as you remember. But do not take if it is too late or almost time for your next dose. Do not increase your recommended dose. Take your usually dose next day in the same regularly time.



Overdose

Deaths have been reported in patients who overdosed, so you may be more careful with taking this medication. Symptoms of Symmetrel overdose may include fever, anxiety, severe headache, confusion, hallucinations, agitation, aggression, personality changes, tremor, problems with balance or walking, fast or uneven heart rate, urinating less than usual or not at all, trouble breathing, seizure (convulsion), or fainting. If you experience one of them call your doctor immediately.



Storage

Store at room temperature between 59-77 degrees F (15-25 degrees C) away from light and moisture, kids and pets. Do not use after expiration term.



Disclaimer

We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)