Possible food and drug interactions when taking Symmetrel

Consumer Information (Cerner Multum)

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 amantadine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to amantadine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies have not been done in humans. However, there have been reports of birth defects, including birth defects of the heart, when women took amantadine during the first trimester of pregnancy. Also, a malformation involving the lower leg occurred in one infant. In addition, studies in some animals have shown that amantadine is harmful to the fetus and causes birth defects. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—Amantadine passes into breast milk. However, the effects of amantadine in newborn babies and infants are not known. It may be necessary for you to take another medicine or to stop breast-feeding during treatment. Be sure you have discussed the risks and benefits of the medicine with your doctor.

Children—This medicine has been tested in children over 1 year of age and has not been shown to cause different side effects or problems in these children than it does in adults. There is no specific information comparing the use of amantadine in children under 1 year of age with use in other age groups.

Older adults—Elderly people are especially sensitive to the effects of amantadine. Confusion, difficult urination, blurred vision, constipation, and dry mouth, nose, and throat may be especially likely to occur.

Other 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 amantadine, it is especially important that your health care professional know if you are taking any of the following:

• Amphetamines or
• Appetite suppressants (diet pills), except fenfluramine (e.g., Pondimin), or
• Caffeine (e.g., NoDoz) or
• Chlophedianol (e.g., Ulone) or
• Cocaine or
• Medicine for asthma or other breathing problems or
• Medicine for colds, sinus problems, or hay fever or other allergies (including nose drops or sprays) or
• Methylphenidate (e.g., Ritalin) or
• Nabilone (e.g., Cesamet) or
• Pemoline (e.g., Cylert)—The use of amantadine with these medicines may increase the chance of unwanted effects such as nervousness, irritability, trouble in sleeping, and possibly seizures or irregular heartbeat

• Anticholinergics (medicine for abdominal or stomach spasms or cramps)—The use of amantadine with these medicines may increase the chance of unwanted effects such as blurred vision, dryness of the mouth, confusion, hallucinations, and nightmares

• Quinidine (e.g., Quinaglute Dura-tabs, Quinidex Extentabs) or
• Quinine or
• Trimethoprim and sulfamethoxazole (e.g., Bactrim, Septra)—These medicines may increase the amount of amantadine in the blood and increase the chance for side effects

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

• Eczema (recurring)—Amantadine may cause or worsen eczema

• Epilepsy or other seizure disorder (history of)—Amantadine may increase the frequency of convulsions (seizures) in patients with a seizure disorder

• Heart disease or other circulation problems or
• Swelling of feet and ankles—Amantadine may increase the chance of swelling of the feet and ankles, and may worsen heart disease or circulation problems

• Kidney disease—Amantadine is removed from the body by the kidneys; patients with kidney disease will need to receive a lower dose of amantadine

• Mental or emotional illness—Higher doses of amantadine may cause confusion, hallucinations, and nightmares

• Substance abuse (drug or alcohol abuse), history of—The chance of side effects from this medicine may be increased