Drug Facts: Namenda (memantine)

August 3, 2010

Generic name: memantine

Sold as 10 mg capsules (gray, with the number “10” on one side and the letters “FL” on the other) and 5 mg capsules (tan, with “5” on one side “FL” on the other).

Why It’s Prescribed
To ease the symptoms of moderate to severe Alzheimer’s disease. May slow the mental and physical deterioration seen in the later stages of Alzheimer’s. However, it does not halt disease progression long term.

Who Benefits
People with mild to moderate Alzheimer’s disease. In one six-month study, patients deteriorated about half as much as they would have if they had not been taking the drug. The main benefit comes later in the course of the illness, when it may improve quality of life for patients and caregivers alike. However, improvements may be very subtle, and it does not work for everybody.

How it Works
Shields brain cells from overexposure to a chemical called glutamate, excess levels of which contribute to the death of brain cells in people with Alzheimer’s. However, there is no evidence the drug protects brain cells or halts or reverses the downward spiral of symptoms long term.

Dosage Guidelines
To start, 5 mg once a day. The dose is gradually increased to a daily total dose of 20 mg, taken in two doses. Can be taken with or without food.

Onset of Effect
Benefits, if they occur, may be noticed within several weeks of starting the drug.

Store in a tightly sealed container away from heat, moisture and light.

Missed Dose
Skip the missed dose and resume your regular schedule.

Long-term Use
The drug is taken long term and may move the clock back a few months, but the disease continues to progress. If the drug seems to stop working, your doctor may switch you off the drug.

Side Effects
Serious: There are no serious side effects.
Most common: Dizziness, headache, constipation, confusion, skin rash. These side effects may diminish within several weeks.
Less common: Fatigue, general achiness, back pain, high blood pressure, vomiting, trouble sleeping, hallucinations, coughs, shortness of breath.

Precautions & Special Concerns
Patients with kidney problems may not be able to tolerate this drug.

When to Call the Doctor
If you experience troublesome side effects or the drug seems to stop working.

In Case of Overdose: Symptoms & What to Do
Restlessness, psychosis, visual hallucinations, stupor, loss of consciousness. Call your doctor, emergency medical services, or poison control center immediately.

Drug Interactions
May interact with amantadine, ketamine, and dextromethorphan. May alter levels of various drugs, including diuretics (hydrochlorothiazide, triamterene), ulcer drugs (cimetidine, ranitidine) and quinidine.

Food Interactions
No known food interactions.

Disease Interactions
People with mild kidney problems may need to take a low dose. Those with severe kidney disease may not be able to tolerate it at all.

Expert comment
“For some people with Alzheimer’s disease, this drug can lead to improvements that the family can see. In others, responses may only be detectable under special testing conditions, or there may be no measurable response at all. It is important that family members and physicians maintain realistic expectations for drug therapy and remember that, as with all current Alzheimer’s drugs, responses are generally only modest at best.” –Samuel E. Gandy, M.D., Ph.D., Scientific Advisory Board, Fisher Center for Alzheimer’s Research Foundation


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