AMANTADINE (Systemic)
Some commonly used brand names are:
In the U.S.?
In Canada?
- Endantadine
- Gen-Amantadine
- Symmetrel
Generic name product may be available in the U.S. and Canada.
Category
- Antidyskinetic
- Antifatigue,specifically in multiple sclerosis
- Antiviral,systemic
Description
Amantadine (a-MAN-ta-deen)is an antiviral. It is used to prevent or treat certain influenza (flu) infections(type A). It may be given alone or along with flu shots. Amantadine will notwork for colds, other types of flu, or other virus infections.
Amantadine also is an antidyskinetic. It is used to treat Parkinson's disease,sometimes called paralysis agitans or shaking palsy. It may be given aloneor with other medicines for Parkinson's disease. By improving muscle controland reducing stiffness, this medicine allows more normal movements of thebody as the disease symptoms are reduced. Amantadine is also used to treatstiffness and shaking caused by certain medicines used to treat nervous, mental,and emotional conditions.
Amantadine may be used for other conditions as determined by your doctor.
Amantadine is available only with your doctor's prescription, in the followingdosage forms:
Oral- Capsules (U.S. and Canada)
- Syrup (U.S. and Canada)
- Tablets (U.S.)
Before Using This Medicine
In deciding to use a medicine,the risks of taking the medicine must be weighed against the good it willdo. This is a decision you and your doctor will make. For amantadine, thefollowing should be considered:
Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to amantadine. Also tell your health care professional ifyou are allergic to any other substances, such as foods, preservatives, ordyes.
Pregnancy?Studies have not been done in humans. However, therehave 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 fetusand causes birth defects. Before taking this medicine, make sure your doctorknows if you are pregnant or if you may become pregnant.
Breast-feeding?Amantadine passes into breast milk. However, theeffects of amantadine in newborn babies and infants are not known. It maybe necessary for you to take another medicine or to stop breast-feeding duringtreatment. Be sure you have discussed the risks and benefits of the medicinewith your doctor.
Children?This medicine has been tested in children over 1year of age and has not been shown to cause different side effects or problemsin these children than it does in adults. There is no specific informationcomparing the use of amantadine in children under 1 year of age with use inother age groups.
Older adults?Elderly people are especially sensitive to the effectsof 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 usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. When you are takingamantadine, it is especially important that your health care professionalknow 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 medicinesmay 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)?Theuse of amantadine with these medicines may increase the chance of unwantedeffects 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)?Thesemedicines may increase the amount of amantadine in the blood and increasethe chance for side effects
Other medical problems?The presence of other medicalproblems may affect the use of amantadine. Make sure you tell your doctorif you have any other medical problems, especially:
- Eczema (recurring)?Amantadine may cause or worsen eczema
- Epilepsy or other seizure disorder (history of)?Amantadinemay increase the frequency of convulsions (seizures) in patients with a seizuredisorder
- Heart disease or other circulation problems or
- Swelling of feet and ankles?Amantadine may increase the chanceof swelling of the feet and ankles, and may worsen heart disease or circulationproblems
- 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 maycause confusion, hallucinations, and nightmares
- Substance abuse (drug or alcohol abuse), history of?The chanceof side effects from this medicine may be increased
Proper Use of This Medicine
For patients taking amantadine to prevent or treat flu infections:
- Talk to your doctor about the possibility of getting a flu shot ifyou have not had one yet.
- This medicine is best taken before exposure,or as soon as possible after exposure, to people who have the flu.
- To help keep yourself from getting the flu, keep taking this medicine for the full time of treatment. Or if youalready have the flu, continue taking this medicine for the full time of treatmenteven if you begin to feel better after a few days. This will help to clearup your infection completely. If you stop taking this medicine too soon, yoursymptoms may return. This medicine should be taken for at least 2 days afterall your flu symptoms have disappeared.
- This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses.Also, it is best to take the doses at evenly spaced times day and night.For example, if you are to take two doses a day, the doses should be spacedabout 12 hours apart. If this interferes with your sleep or other daily activities,or if you need help in planning the best times to take your medicine, checkwith your health care professional.
- If you are using the oral liquid form of amantadine, use a speciallymarked measuring spoon or other device to measure each dose accurately. Theaverage household teaspoon may not hold the right amount of liquid.
For patients taking amantadine for Parkinson's diseaseor movement problems caused by certain medicines used to treat nervous,mental, and emotional conditions:
- Take this medicine exactly as directed by yourdoctor. Do not miss any doses and do not take more medicine than yourdoctor ordered.
- Improvement in the symptoms of Parkinson's disease usually occursin about 2 days. However, in some patients this medicine must be taken forup to 2 weeks before full benefit is seen.
Dosing?The dose of amantadine will be different fordifferent patients. Follow your doctor's orders or thedirections on the label. The following information includes only theaverage doses of amantadine. Your dose may be different if you have kidneydisease. If your dose is different, do not change it unless your doctor tells you to do so. The number of capsules, tablets,or teaspoonfuls of suspension that you take depends on the strength of themedicine. Also, the number of doses you take each day,the time allowed between doses, and the length of time you take the medicinedepend on the medical problem for which you are taking amantadine.
- For oral dosage forms (capsules, syrup,and tablets):
- For the treatment or prevention of flu:
- Older adults?100 milligrams once a day.
- Adults and children 12 years of age and older?200 milligramsonce a day, or 100 milligrams two times a day.
- Children 9 to 12 years of age?100 milligrams two times a day.
- Children 1 to 9 years of age?Dose is based on body weight andmust be determined by the doctor.
- Children up to 1 year of age?Use and dose must be determinedby your doctor
- For the treatment of Parkinson's disease ormovement problems:
- Older adults?100 milligrams once a day to start. The dose maybe increased slowly over time, if needed.
- Adults?100 milligrams one or two times a day. Your doctor mayincrease this dose, if needed.
- Children?Dose has not been determined.
Missed dose?If you miss a dose of this medicine, take it assoon as possible. This will help to keep a constant amount of medicine inthe blood. However, if it is almost time for your next dose, skip the misseddose and go back to your regular dosing schedule. Do not double doses.
Storage?To store this medicine:
- Keep out of the reach of children.
- Store away from heat and direct light.
- Do not store the capsule form of this medicine in the bathroom, nearthe kitchen sink, or in other damp places. Heat or moisture may cause themedicine to break down.
- Keep the oral liquid form of this medicine from freezing.
- Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.
Precautions While Using This Medicine
Drinkingalcoholic beverages while taking this medicine may cause increased side effectssuch as circulation problems, dizziness, lightheadedness, fainting, or confusion.Therefore, do not drink alcoholic beverages while youare taking this medicine.
This medicine may cause some people to become dizzy, confused, or lightheaded,or to have blurred vision or trouble concentrating. Make sure you know how you react to this medicine before you drive, use machines,or do anything else that could be dangerous if you are dizzy or are not alertor able to see well. If these reactions are especially bothersome,check with your doctor.
Getting up suddenly from a lying or sitting position also may be a problembecause of the dizziness, lightheadedness, or fainting that may be causedby this medicine. Getting up slowly may help. If this problem continues orgets worse, check with your doctor.
If amantadine causes you to feel very depressed orto have thoughts of suicide, check with your doctor immediately.
Amantadine may cause dryness of the mouth, nose, and throat. For temporaryrelief of mouth dryness, use sugarless candy or gum, melt bits of ice in yourmouth, or use a saliva substitute. However, if your mouth continues to feeldry for more than 2 weeks, check with your doctor or dentist. Continuing drynessof 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 and/orfeet after this medicine has been taken regularly for a month or more. Althoughthe blotchy spots may remain as long as you are taking this medicine, theyusually go away gradually within 2 to 12 weeks after you stop taking the medicine.If you have any questions about this, check with your doctor.
For patients taking amantadine to prevent or treatflu infections:
- If your symptoms do not improve within a few days, if they becomeworse, or you develop new symptoms, check with your doctor.
For patients taking amantadine for Parkinson's diseaseor movement problems caused by certain medicines used to treat nervous,mental, and emotional conditions:
- Patients with Parkinson's disease must be carefulnot to overdo physical activities as their condition improves and body movementsbecome easier since injuries resulting from falls may occur. Such activitiesmust be gradually increased to give your body time to adjust to changing balance,circulation, and coordination.
- Some patients may notice that this medicine gradually loses its effectwhile they are taking it regularly for a few months. If you notice this, checkwith your doctor. Your doctor may want to adjust the dose or stop the medicinefor a while and then restart it to restore its effect.
- Do not suddenly stop taking this medicine withoutfirst checking with your doctor since your Parkinson's disease mayget worse very quickly. Your doctor may want you to reduce your dose graduallybefore stopping the medicine completely.
Side Effects of This Medicine
Along with its needed effects,a medicine may cause some unwanted effects. Although not all of these sideeffects may occur, if they do occur they may need medical attention.
Check with your doctorimmediately if any of the following side effects occur:
Less common
Blurred vision; confusion (especiallyin elderly patients); difficult urination (especiallyin elderly patients); fainting; hallucinations (seeing, hearing, or feeling things that are not there); swelling of hands, feet, or lower legs
Rare
Convulsions (seizures); decreased visionor any change in vision; difficulty in coordination; fever, chills, or sore throat; increased blood pressure; increase in body movements; irritation and swelling of the eye; loss of memory; mental depression; severe mood or mental changes; skinrash; slurred speech; thoughtsof suicide or attempts at suicide; unexplained shortnessof breath
Other side effects may occur that usually do not need medicalattention. These side effects may go away during treatment as your body adjuststo the medicine. However, check with your doctor if any of the following sideeffects continue or are bothersome:
More common
Agitation, anxiety, or nervousness; difficulty concentrating; dizziness or lightheadedness; headache; irritability; loss of appetite; nausea; purplish red, net-like, blotchy spots on skin; trouble in sleeping or nightmares
Other side effects notlisted above may also occur in some patients. If you notice any other effects,check with your doctor.
Additional Information
Once a medicine has been approvedfor marketing for a certain use, experience may show that it is also usefulfor other medical problems. Although this use is not included in product labeling,amantadine is used in certain patients with the following medical condition:
- Unusual tiredness or weakness associated with multiple sclerosis
Other than the above information, there is no additional information relatingto proper use, precautions, or side effects for this use.
Revised: 05/21/2001
