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Symmetrel (Oral)

Generic name: amantadinea-MAN-ta-deen ]
Brand names: Gocovri, Osmolex ER, Symmetrel
Drug classes: Adamantane antivirals, Dopaminergic antiparkinsonism agents

Medically reviewed by Drugs.com. Last updated on Jul 30, 2023.

Uses for Symmetrel

Amantadine is an antidyskinetic medicine. It is used to treat Parkinson's disease (sometimes called "paralysis agitans" or "shaking palsy") and its symptoms, including dyskinesia (sudden uncontrolled movements). It may be given alone or in combination with other medicines (eg, levodopa) for Parkinson's disease. By improving muscle control and reducing stiffness, this medicine allows more normal movements of the body as the disease symptoms are reduced. Amantadine is also used to treat stiffness and shakiness caused by certain medicines that are used to treat nervous, mental, and emotional conditions.

Amantadine is also an antiviral medicine. It is used to prevent or treat certain influenza (flu) infections (type A). It may be given alone or together with flu shots. Amantadine will not work for colds, other types of flu, or other virus infections.

This medicine is available only with your doctor's prescription.

Before using Symmetrel

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of Gocovri® and Osmolex ER™ in the pediatric population. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of amantadine in the elderly. Elderly patients are also more likely to have unwanted effects (eg, falls, hallucinations) and age-related kidney disease, which may require caution in patients receiving Gocovri® and Osmolex ER™.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of Symmetrel

For patients taking amantadine for Parkinson's disease or movement problems (including dyskinesia) caused by certain medicines used to treat nervous, mental, and emotional conditions:

For patients taking amantadine to prevent or treat flu infections:

Take Gocovri® extended-release capsule at bedtime. Swallow whole. Do not crush, break, or chew it. You may also open and sprinkle the extended-release capsules on a teaspoonful of soft food, including applesauce. Take all of the medicine right away without chewing. You may take this medicine with or without food.

Take Osmolex ER™ extended-release tablet in the morning. Swallow whole. Do not crush, open, or chew it.

Do not receive the nasal flu vaccine (live attenuated influenza vaccine) while taking this medicine.

Do not drink alcohol while you are using this medicine.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you miss a dose of amantidine, skip the missed dose and take your next dose at your usual time. Do not take extra medicine to make up for a missed dose.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using Symmetrel

It is very important that your doctor check your progress at regular visits to see if the medicine is working properly and to allow changes in your dose. Blood and urine tests may be needed to check for any unwanted effects.

Amantadine may cause some people to be agitated, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. Also tell your doctor if you have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared. If you, your child, or your caregiver notice any of these adverse effects, tell your doctor or your child's doctor right away.

Some people who have used this medicine had unusual changes in their behavior. Talk with your doctor right away if you start having unusual urges, such as gambling urges, binge or compulsive eating, compulsive shopping, or sexual urges while using this medicine.

Drinking alcoholic beverages while taking this medicine may cause increased side effects, such as circulation problems, dizziness, lightheadedness, fainting, or confusion. Do not drink alcoholic beverages while you are taking this medicine.

This medicine may cause some people to become dizzy, drowsy, or lightheaded, or to have blurred vision or trouble concentrating. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Dizziness, lightheadedness, or fainting may occur with this medicine, especially when you suddenly get up from a lying or sitting position. These symptoms are more likely to occur when you begin taking this medicine or when the dose is increased. Getting up slowly may help. If this problem continues or gets worse, check with your doctor.

Patients with Parkinson's disease must be careful not to overdo physical activities when their condition improves and body movements become easier, since injuries resulting from falls may occur. Such activities must be gradually increased to give your body time to adjust to a change in balance, circulation, and coordination.

Amantadine may cause dryness of the mouth, nose, and throat. For temporary relief of mouth dryness, use sugarless candy or gum, melted bits of ice in your mouth, or use a saliva substitute. If your mouth continues to feel dry for more than 2 weeks, check with your doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

This medicine may cause purplish red, net-like, blotchy spots on the skin. This problem occurs more often in females and usually occurs on the legs or feet after this medicine has been taken regularly for a month or more. Although the blotchy spots may remain as long as you are taking this medicine, they will usually go away gradually within 2 to 12 weeks after you stop taking the medicine. If you have any questions about this, talk with your doctor.

Check with your doctor right away if you are having convulsions (seizures), difficulty with breathing, a fast heartbeat, a high fever, high or low blood pressure, increased sweating, loss of bladder control, severe muscle stiffness, unusually pale skin, or tiredness. These could be symptoms of a serious condition called neuroleptic malignant syndrome (NMS).

If you are using this medicine for Parkinson's disease, do not stop taking this medicine suddenly without first checking with your doctor. Your doctor may want you to slowly reduce the amount you are using before stopping it completely.

If you are using this medicine for Parkinson's disease, it is important that your doctor check your skin regularly for signs of melanoma (skin cancer). If you notice any unusual red, brown, or black spots on your skin, check with your doctor right away.

If your Parkinson's symptoms do not improve within a few days, if they become worse, or if this medicine appears less effective after a few weeks, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of Symmetrel

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Less common

Rare

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Commonly used brand name(s)

In the U.S.

Available Dosage Forms:

Therapeutic Class: Antiparkinsonian

Pharmacologic Class: Anticholinergic

Chemical Class: Adamantane

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.