Namenda (memantine hydrochloride) is a prescription drug that’s used to treat dementia caused by Alzheimer’s disease. Namenda can cause side effects that range from mild to serious. Examples include dizziness and headache.

Specifically, Namenda is used in adults to treat moderate to severe dementia caused by Alzheimer’s disease.

The active ingredient in Namenda is memantine hydrochloride. The drug comes in two oral forms: a tablet (Namenda) and an extended-release capsule (Namenda XR). (“Extended release” means the drug is released into your body slowly over a period of time.)

Keep reading to learn about the common, mild, and serious side effects that Namenda can cause. For a general overview of the drug, including details about its uses, see this article.

Note: As a person’s condition progresses, they may need help reading or understanding certain information about their treatment plan. This article contains details that may help caregivers learn more about key aspects of Namenda.

Keeping track of side effects

During your Namenda treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Namenda affects you. They can then use this information to adjust your treatment plan if needed.

Below are just a few of the more common side effects reported by people who took Namenda in studies. These side effects can vary depending on the form of the drug you’re taking.

More common side effects reported in people taking Namenda include:

More common side effects reported in people taking Namenda XR include:

  • headache
  • diarrhea
  • dizziness

These aren’t the only side effects that Namenda can cause. Read on to learn about other possible side effects of Namenda. Each person’s experience with side effects may differ.

Mild side effects have been reported with Namenda and Namenda XR. These include:

In most cases, these side effects should be temporary. And some may be managed easily. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop taking Namenda unless your doctor recommends it.

Namenda may cause mild side effects other than those listed above. See the prescribing information for Namenda or Namenda XR for details.

Allergic reaction

For some people, Namenda can cause an allergic reaction. But it’s not clear whether this side effect occurred in studies of Namenda and Namenda XR.

In general, symptoms of allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should keep taking Namenda.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 right away. Or call your local emergency number. These symptoms could be life threatening and require immediate medical care.

Your doctor can confirm whether you’ve had a serious allergic reaction to Namenda. If they do, they may have you switch to a different treatment.

Serious side effects have been reported with Namenda and Namenda XR. These include:

Of the serious side effects noted above, the following were not reported in studies of Namenda or Namenda XR, but they have occurred in people after the drug was approved for use:

  • mental health changes, such as hallucinations and suicidal thoughts and behavior
  • SJS
  • heart failure
  • kidney failure

You can learn more about the following serious side effects in the “Side effects explained” section below:

  • mental health changes
  • SJS

If you develop serious side effects while taking Namenda, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911. Or call your local emergency number.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Namenda, visit MedWatch.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you are not in the same household, stay on the phone with them until help arrives.

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Below is important information you should consider before taking Namenda.

Warnings

Namenda can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Namenda is a good treatment option for you.

Talk with your doctor about your health history before you take Namenda. Be sure to tell them if any of the following factors apply to you:

Get answers to some frequently asked questions about Namenda’s side effects.

Can memantine, Namenda’s generic version, make dementia worse?

To answer this, you need an understanding of what Namenda and memantine can and cannot do. Although both drugs are approved to treat dementia caused by Alzheimer’s disease, they cannot cure the condition. Instead, they can slow the progression of the disease. This means a person’s dementia can still worsen over time even if they’re taking Namenda or memantine.

Also, confusion is a common side effect of Namenda. And confusion is also one of the symptoms of dementia. So taking Namenda might make it seem like your dementia is worsening.

Namenda is a brand-name drug, and its generic version is memantine. A generic medication is an identical copy of the active drug in a brand-name medication. Generic drugs are believed to be as effective and safe as brand-name drugs.

If your dementia seems to be getting worse or you’re experiencing severe confusion while taking Namenda, talk with your doctor.

Does Namenda cause different side effects in the elderly?

It’s not likely. In studies of Namenda and Namenda XR, older adults experienced side effects similar to those in younger adults. (Older adults are ages 65 years and older.)

If you’re concerned about the safety of Namenda given your age, talk with your doctor.

Does Namenda cause long-term side effects?

It’s unlikely. Long-term side effects were not reported in studies of Namenda and Namenda XR.

If you’re concerned about possible long-term side effects from Namenda, talk with your doctor or pharmacist.

Learn more about some of the side effects Namenda may cause.

Confusion

Confusion was a common side effect reported in studies of Namenda. But it wasn’t reported in studies of Namenda XR.

Confusion is when you cannot think clearly. With confusion, you may have a hard time focusing or making decisions. Confusion is also one of the symptoms of dementia.

Signs of confusion may include:

  • difficulty speaking
  • incoherent speech
  • slurring of words
  • forgetting what you’re doing while completing a task
  • being unaware of the location or time

Extreme confusion can lead to delirium, which is a sudden change in your mental state.

What might help

If you experience confusion during Namenda treatment, consider asking a loved one for help. You may need help doing things you’ve done on your own before. You should also talk with your doctor. They can help determine the cause of your confusion and recommend the appropriate treatment.

Mental health changes

Namenda and Namenda XR can cause mental health changes. These include hallucinations and suicidal thoughts and behaviors. But it’s unclear how often suicidal thoughts and behaviors occurred and whether Namenda was the cause.

Anxiety is a feeling of fear, apprehension, or uneasiness. Depression is a mood disorder that involves feelings of sadness, loss, or anger. With hallucinations, a person sees or hears things that aren’t real.

What might help

If you experience any mental health changes while taking Namenda, talk with your doctor right away. Also let them know right away if you have suicidal thoughts or behaviors. They can help determine the cause and whether you should continue taking Namenda. If needed, they can also refer you to a mental health professional for treatment.

SJS

SJS has occurred in people taking Namenda and Namenda XR. This side effect did not occur in studies of the drugs, but it was reported after the drugs were approved for use. It’s unclear how often this occurred and whether Namenda was the cause.

SJS is a rare but serious skin reaction that can cause your skin to loosen and detach from your body. Symptoms may include:

  • blistering rash that may or may not involve your mucous membranes
  • sore throat
  • cough
  • red eyes
  • muscle aches
  • peeling skin

What might help

SJS is a potentially life threatening condition that requires immediate medical care. Get medical help right away if you develop any symptoms of SJS and if any of the following apply to you:

  • You started a new medication in the last 8 weeks.
  • You have a rash that resembles the skin reaction of SJS.
  • You have a personal or family history of SJS or toxic epidermal necrolysis (TEN).

Your doctor will likely have you stop taking Namenda and provide treatment for your symptoms.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.