Namenda (Memantine) - Oral

What Is Namenda?

Namenda (memantine) is an oral prescription medication used to help treat the symptoms of dementia from Alzheimer’s disease. 

Namenda is an N-methyl-D-aspartate (NMDA) receptor antagonist. It binds to the NMDA receptors in the brain, which are believed to play a role in Alzheimer’s disease, to decrease abnormal brain activity. Taking Namenda will not cure the disease, but it may help improve symptoms.

This medication is available in standard formulation tablets, extended-release (XR) capsules, and a solution (liquid).

Drug Facts

Generic Name: Memantine

Brand Name(s): Namenda, Namenda XR

Administration Route: Oral

Drug Availability: Prescription

Therapeutic Classification: Anti-Alzheimer's agent

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Memantine

Dosage Form(s): Tablet, solution, extended-release capsule

What Is Namenda Used For?

The Food and Drug Administration (FDA) approved Namenda for use in adults to treat moderate to severe Alzheimer’s dementia.

Alzheimer’s disease is a progressively worsening brain condition that causes memory and behavioral changes, usually starting after the age of 60. Namenda is not a cure for Alzheimer’s disease and will not prevent the eventual decline in cognitive abilities. However, it can help improve symptoms or may slow the loss of cognitive skills.

Namenda (Memantine) Drug Information - Illustration by Zoe Hansen

Verywell / Zoe Hansen

How to Take Namenda 

Usually, your healthcare provider will prescribe Namenda for you or your loved one at a low dose and increase it gradually. The dosing schedule will increase the dose no more than once every week. 

Namenda can be taken with or without food. The tablets and solution are usually taken either once or twice a day, and the XR capsule is taken once a day. The capsules can be swallowed whole or opened and sprinkled on applesauce before consumption. Do not take only a partial dose or save the rest for later.


Keep this medication in its original container and away from the reach of children or pets.  

Store the standard Namenda tablets and capsules between 68 degrees to 77 degrees Fahrenheit (F). It can be briefly kept in temperatures as low as 59 degrees and high as 86 degrees F.

Off-Label Uses 

This medication has been prescribed for several off-label uses or conditions that it is not specifically approved to treat. 

Off-label uses include:

  • Dementia that is not caused by Alzheimer’s disease 
  • Korsakoff syndrome
  • Autism disorder symptoms
  • Neuropathic pain 

The effects and dose for off-label uses have not been established.

How Long Does Namenda Take to Work?

The clinical effects of Namenda can take weeks or months to occur, and they are not always apparent to everyone. It may help improve the symptoms associated with Alzheimer's disease in the short term, but it will not stop the disease long-term.

What Are the Side Effects of Namenda?

This medication can cause side effects, and the side effects of the standard formulation and the XR formulation are similar, but there are some differences.  

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at or 1-800-FDA-1088.

Common Side Effects

The most common side effects caused by the standard formulation of Namenda are:

The most common side effects of the XR formulation are:

Talk to a healthcare provider about treatment options for side effects if you notice any of these while you or a loved one are taking Namenda.

Report Side Effects

Namenda may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Namenda Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For treatment of Alzheimer's disease:
    • For oral dosage form (extended-release capsules):
      • Adults—At first, 7 milligrams (mg) once a day. Your doctor may gradually increase your dose as needed. However, the dose is usually not more than 28 mg per day.
      • Children—Use and dose must be determined by your doctor.
    • For oral dosage form (solution and tablets):
      • Adults—At first, 5 milligrams (mg) once a day. Your doctor may gradually increase your dose as needed. However, the dose is usually not more than 10 mg two times a day.
      • Children—Use and dose must be determined by your doctor.


It is recommended that people who have severe kidney failure take one-half of the regular dose of Namenda or Namenda XR.

There are no established differences in the effectiveness of Namenda and Namenda XR. If you are switching from Namenda 10 milligrams twice a day to the XR formulation, you will take 28 milligrams of the XR formulation once a day, starting the day after your last 10 milligrams dose of Namenda.

Missed Dose 

The instructions for missed doses depend on whether you take the standard formulation or the XR formulation: 

  • For standard twice daily Namenda: If you miss a dose, take your next dose as scheduled and do not double up on your dose.
  • For Namenda XR: If you miss your dose, you should try to take it as soon as possible. If it’s close to the time of your next dose, you should take your next dose as scheduled and don’t double up.

If you miss your dose for a few days, your healthcare provider might recommend restarting the medication at a lower dose and gradually working up to your target dose.

Overdose: What Happens If I Take Too Much Namenda?

Tell your healthcare provider if you take more Namenda than prescribed. Depending on how much you’ve taken, you may need medical observation so healthcare providers can detect the effects of an overdose if they occur. 

An overdose can potentially cause the following symptoms:

  • Agitation or restlessness
  • Lack of energy, tiredness, slow movement, or generalized weakness
  • Dizziness
  • Decreased balance
  • Vomiting
  • Low heart rate or electrocardiogram (EKG) changes
  • High blood pressure
  • Confusion
  • Loss of consciousness
  • Psychosis or hallucinations
  • Coma

You might not experience any symptoms from taking too much Namenda. If you do develop symptoms, you may need to seek medical attention for treatment.

What Happens If I Overdose on Namenda?

If you think you or someone else may have overdosed on Namenda, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses, has a seizure, has trouble breathing, or can’t wake up after taking too much Namenda, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Namenda?

You should not take this medication if you have ever had an allergic reaction to Namenda or any other components present in the formulation.

What Other Medications Interact With Namenda?

Medications that alter the urine pH can cause a high blood level of Namenda. These medications can include carbonic anhydrase inhibitors or sodium bicarbonate.

This medication should be used with caution if taken with other NMDA antagonists (e.g., amantadine, ketamine, and dextromethorphan).

What Medications Are Similar?

Other medications used to treat the symptoms of Alzheimer’s disease include:

  • Namzaric (donepezil and memantine), which is a combination NMDA receptor antagonist and a cholinesterase inhibitor
  • Aricept (donepezil), Exelon (rivastigmine), and Razadyne (galantamine), which are cholinesterase inhibitors
  • Aduhelm (aducanumab) is an anti-amyloid antibody intravenous infusion therapy

Typically, only one medication is prescribed to treat Alzheimer’s disease. There is no evidence suggesting that taking more than one at a time could be beneficial.

Frequently Asked Questions

  • What is Namenda used for?

    Namenda is often prescribed for treating Alzheimer’s dementia symptoms. It is sometimes prescribed off-label for treating other types of dementia. 

  • How does Namenda work?

    Namenda is an N-methyl-D-aspartate (NMDA) receptor antagonist. Overactivity of these receptors is thought to be associated with Alzheimer’s disease. 

  • What drugs should not be taken with Namenda?

    This drug can reach excessive levels in the body if you take any medications that could change the urine pH. Additionally, taking this medication with other NMDA receptor antagonists may increase the risk of side effects.

  • How long does it take for Namenda to work?

    The clinical effects of Namenda can take weeks or months to occur, and they are not always apparent for everyone. Generally, this medication slows the progression of Alzheimer’s dementia symptoms, but it does not reverse them.

  • What are the side effects of Namenda?

    This medication can cause headaches and dizziness. The standard formulation also can cause constipation and confusion, and the XR formulation can also cause diarrhea.

  • How do I stop taking Namenda?

    It is generally considered safe to stop taking Namenda. If you restart, your healthcare provider will need to resume your regimen at a low dose and gradually increase it until you reach a target dose.

How Can I Stay Healthy While Taking Namenda?

If you are taking Namenda, it’s important that you also take steps to stay healthy. It can be scary and overwhelming to receive a diagnosis of Alzheimer's disease and cope with its symptoms. This can also be similar for those whose loved ones have been diagnosed and are dealing with this condition. 

Stay healthy while taking Namenda includes:

  • Keeping up with your medical care so your healthcare provider and family can periodically reassess the amount of support you need.
  • Avoiding things that could be dangerous for you, such as driving, using sharp instruments, or cooking while you are alone.
  • If you are also taking other medications, make sure you take them as scheduled, and consider using reminders or having a family member help you with your medications.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Food and Drug Administration. Namenda label.

  4. Food and Drug Administration. Namenda XR label.

  5. Rossignol DA, Frye RE. The use of medications approved for Alzheimer's disease in autism spectrum disorder: a systematic review. Front Pediatr. 2014;2:87. doi:10.3389/fped.2014.00087