amantadine, Symmetrel (Discontinued) (cont.)

Pharmacy Author:

Omudhome Ogbru, PharmD

Omudhome Ogbru, PharmD

Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

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Medical and Pharmacy Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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Since amantadine amplifies the actions of dopamine in the brain, drugs which block the effects of dopamine should be avoided in persons taking amantadine when amantadine is used for the treatment of Parkinson's disease. Such drugs include haloperidol (Haldol), metoclopramide (Reglan), and phenothiazines, for example, thioridazine (Mellaril) or triflupromazine (Stelazine). The use of the diuretics hydrochlorothiazide or triamterene (Dyazide; Maxzide) with amantadine can reduce the kidney's ability to eliminate amantadine. This can lead to high levels of amantadine in the blood and amantadine-associated toxicity.

PREGNANCY: No well-controlled studies have been done in pregnant women to evaluate amantadine's safety. Physicians may choose to use amantadine during pregnancy when the potential benefits outweigh the potential but unknown risks to the fetus.

NURSING MOTHERS: Amantadine is excreted into breast milk in low concentrations. Although no information is available on the effects in infants, the manufacturer recommends that amantadine be used cautiously in women who are breastfeeding.

SIDE EFFECTS: The most frequent side effects associated with amantadine include dizziness, loss of coordination, inability to sleep, nervousness, nausea, and vomiting. Effects can appear after a few hours or several days of therapy. Less common side effects include headache, irritability, nightmares, depression, confusion, drowsiness, hallucinations, weakness, amnesia, slurred speech, diarrhea, constipation, loss of appetite, and discolorations in the eye.

Reference: FDA Prescribing Information

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