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).

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.

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.

Storage 

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.

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 fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

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

• Dizziness
• Headaches
• Confusion
• Constipation

The most common side effects of the XR formulation are:

• Headaches 
• Diarrhea
• Dizziness

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.

Dosage: How Much Namenda Should I Take?

Modifications 

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.

Precautions

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.

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.