What is Memantine Used For?

Alzheimer’s is so far incurable, but there are medications out there that can help manage symptoms and improve quality of life for patients and their caregivers and loved ones. One of the Alzheimer’s symptoms treatments on the market is memantine, an FDA-approved oral medicine. It isn’t disease-modifying, so it can’t stop or cure Alzheimer’s, but it is designed to treat the symptoms of moderate to severe Alzheimer’s. It’s marketed under brand names including Namenda.

Memantine is an N-methyl-D-aspartate (NMDA, the inspiration for the drug’s brand name Namenda) antagonist that is designed to counteract the process believed to cause brain damage and the death of neurons in the brain — the process that results in Alzheimer’s disease. Doctors prescribe Namenda (memantine) to help people living with Alzheimer’s manage the disease’s symptoms like hallucinations, forgetfulness, confusion, and anxiety, and other aspects of cognitive function. 

Memantine can’t prevent Alzheimer’s from progressing, and it’s not a cure — the disease’s biological processes will still continue to develop in the brain — but is an option for treatment of these symptoms, to try to improve the quality of life for people living with the disease.

Some studies have shown that its brand name drug Namenda works best for people in the later stages of Alzheimer’s — and that the side effects might outweigh the benefits for people in early and moderate stages of the disease.

What is memantine used for, and what are its benefits?

Memantine is an FDA-approved prescription medication for treating Alzheimer’s in combination with a group of medicines called acetylcholinesterase inhibitors (also referred to as cholinesterase inhibitors). It can also be used off-label for treating mild to moderate vascular dementia, psychiatric disorders, chronic pain, and mild cognitive impairment.

Learn more about how
cholinesterase inhibitors work

Memantine helps prevent the aforementioned brain damage and cell death process by preventing the overstimulation of glutamate, a chemical in the brain that, in excess amounts, is thought to lead to Alzheimer’s. Alzheimer’s researchers say more research is needed to fully understand the long-term benefits of taking memantine, but — while, again, it can’t prevent, reverse, or slow neurodegeneration in people with Alzheimer’s disease — they have seen some positive results in the drug’s ability to delay a decline in physical and cognitive functioning and relieve symptoms like restlessness, hallucinations, forgetfulness, and confusion.

What stage of dementia is Namenda (memantine) used for?

Memantine is prescribed for treating dementia in its middle and late stages. This said, Alzheimer’s researchers, including Lon Schneider, MD, MS is Professor of Psychiatry, Neurology, and Gerontology at the Keck School of Medicine of the University of Southern California and colleagues, have tested the drug in people with milder Alzheimer’s and found that it is not effective. 

“Patients with mild Alzheimer’s disease won’t benefit from Namenda—but [it] will cost them money and could cause side effects,”  two Alzheimer’s researchers Dana Casciotti and Stephanie Fox-Rawlings wrote in a review of studies for the National Center for Health Research. Further, they noted in looking at the available research, among people in Alzheimer’s moderate stages, “the effect of Namenda was very small,”

“Looking at the trials separately, only one of the three trials found any statistically significant improvement for patients taking Namenda compared to patients taking placebo,” the researchers wrote of studies into people with moderate Alzheimer’s disease. “Even that improvement was for only one measure – a subjective measure of the doctor or caregiver’s impressions of the patients’ behavior. When the data were combined, there was a statistically significant effect on cognitive functioning and impression of change. However, these differences were small—about half the impact of drugs like Aricept, Exelon, or Razadyne, which are commonly prescribed to treat Alzheimer’s symptoms.”

Their conclusion from the research review was that Namenda only works for severe Alzheimer’s disease.

What are the side effects of taking Namenda (memantine) ?

Memantine causes a range of side effects, some of which may be life-threatening. According to Casciotti and Fox-Rawlings, some of the most common side effects of Namenda include:

• Dizziness
• Confusion
• Headache
• Sleepiness 
• Constipation
• Vomiting
• Pain (especially back pain)
• Coughing

Other side effects might include stomach pain and vomiting, aggressive behavior, hypertension, weight gain, and urinary incontinence.

In rare cases, the label warns this medication may cause even more serious brain, heart, stomach, blood, kidney, liver, muscle, and skin-related problem.

This list doesn’t include every single possible side effect of memantine, and experiences with drugs vary from person to person.

People living with Alzheimer’s who are looking for a safe and effective treatment for their symptoms should talk to a doctor about any symptoms they are experiencing when taking this medication, to understand whether these symptoms might be side effects of the drug. 

What drugs should not be taken with memantine?

When drugs combine in a person’s system, it can change the effects of these drugs, and even be dangerous. Patients who are prescribed Nameda or another brand of memantine should make sure the prescribing physician is aware of all the other drugs they’re taking. According to the UK’s National Health Service, the following drugs can be dangerous when combined with memantine:

• Acetazolamide and brinzolamide: medicines for a group of eye conditions called glaucoma
• Amantadine: medication for treating Parkinson’s disease
• Bupropion: medication for depression and smoking cessation
• Dextromethorphan: cough relief medicine
• Cimetidine: medication for treating ulcers
• Procainamide: medication for managing life-threatening irregular heartbeats
• Ketamine: an anesthesia medication
• Methotrexate: a drug for treating certain cancers
• Quinidine: a medication for treating heart rhythm problems and malaria
• Bicarbonate: a drug designed to treat  indigestion, heartburn, and upset stomach

Talk to a doctor about any medications or supplements you’re on so they can best advise you on taking them when taking memantine. 

How should you take memantine?

Every patient’s experience is different. Consulting with a doctor is the best way to determine if a drug like memantine is a good fit.

According to information provided by the National Institutes of Health, this medication can be taken by mouth as a tablet, liquid medicine, or a long-acting capsule. Patients should consult their prescribing doctor about dosage and whether it should be taken with or without food.