Namenda Side Effects Center

Last updated on RxList: 10/20/2020
Namenda Side Effects Center

What Is Namenda?

Namenda (memantine hydrochloride) is an orally active NMDA receptor antagonist used to treat moderate to severe Alzheimer's type dementia.

What Are Side Effects of Namenda?

Common side effects of Namenda include:

  • tiredness,
  • body aches,
  • joint pain,
  • dizziness,
  • nausea,
  • vomiting,
  • diarrhea,
  • constipation,
  • loss of appetite,
  • weight loss,
  • headache,
  • swelling in your hands or feet,
  • fast heart rate,
  • easy bruising or bleeding,
  • unusual weakness,
  • anxiety,
  • aggression,
  • skin rash,
  • redness or swelling of or around your eyes, or
  • urinating more than usual.

Many people using Namenda do not have serious side effects.

Dosage for Namenda

The recommended starting dose of Namenda is 5 mg once daily. The recommended target dose is 20 mg/day. Dosage is increased in 5 mg increments to 10 mg/day (5 mg twice a day), 15 mg/day (5 mg and 10 mg as separate doses), and 20 mg/day (10 mg twice a day). The minimum recommended interval between dose increases is one week.

What Drugs, Substances, or Supplements Interact with Namenda?

Namenda may interact with cimetidine, nicotine, ranitidine, quinidine, sodium bicarbonate, antiviral medication, cold or cough medicine containing dextromethorphan, diuretics (water pills), medicine to treat glaucoma, or oral diabetes medicine containing metformin. Tell your doctor all prescription and over-the-counter medications you use.

Namenda During Pregnancy and Breastfeeding

Namenda should be used only when prescribed during pregnancy. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Namenda (memantine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


One of the first symptoms of Alzheimer's disease is __________________. See Answer
Namenda Consumer Information

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Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • severe headache, blurred vision, pounding in your neck or ears;
  • seizure (convulsions); or
  • unusual changes in mood or behavior.

Common side effects may include:

  • diarrhea;
  • dizziness; or
  • headache.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Namenda (Memantine HCL)


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Namenda Professional Information


Clinical Trials Experience

NAMENDA was evaluated in eight double-blind placebo-controlled trials involving a total of 1862 dementia (Alzheimer's disease, vascular dementia) patients (940 patients treated with NAMENDA and 922 patients treated with placebo) for a treatment period up to 28 weeks.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Adverse Events Leading to Discontinuation

In placebo-controlled trials in which dementia patients received doses of NAMENDA up to 20 mg/day, the likelihood of discontinuation because of an adverse reaction was the same in the NAMENDA group (10.1%) as in the placebo group (11.5%). No individual adverse reaction was associated with the discontinuation of treatment in 1% or more of NAMENDA-treated patients and at a rate greater than placebo.

Most Common Adverse Reactions

In double-blind placebo-controlled trials involving dementia patients, the most common adverse reactions (incidence ≥ 5% and higher than placebo) in patients treated with NAMENDA were dizziness, headache, confusion and constipation. Table 1 lists all adverse reactions that occurred in at least 2% of patients treated with NAMENDA and at an incidence greater than placebo.

Table 1: Adverse Reactions Reported in Controlled Clinical Trials in at Least 2% of Patients Receiving NAMENDA and at a Higher Frequency than Placebo-treated Patients

Adverse Reaction Placebo
(N = 922) %
(N = 940) %
Body as a Whole
  Fatigue 1 2
  Pain 1 3
Cardiovascular System
  Hypertension 2 4
Central and Peripheral Nervous System
  Dizziness 5 7
  Headache 3 6
Gastrointestinal System
  Constipation 3 5
  Vomiting 2 3
Musculoskeletal System
  Back pain 2 3
Psychiatric Disorders
  Confusion 5 6
  Somnolence 2 3
  Hallucination   2 3
Respiratory System
  Coughing 3 4
  Dyspnea 1 2

The overall profile of adverse reactions and the incidence rates for individual adverse reactions in the subpopulation of patients with moderate to severe Alzheimer's disease were not different from the profile and incidence rates described above for the overall dementia population.


NAMENDA has not been systematically evaluated in patients with a seizure disorder. In clinical trials of NAMENDA, seizures occurred in 0.2% of patients treated with NAMENDA and 0.5% of patients treated with placebo.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of memantine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. These reactions include:

Blood and Lymphatic System Disorders -agranulocytosis, leukopenia (including neutropenia), pancytopenia, thrombocytopenia, thrombotic thrombocytopenic purpura.

Cardiac Disorders -cardiac failure congestive.

Gastrointestinal Disorders -pancreatitis.

Hepatobiliary Disorders – hepatitis.

Psychiatric Disorders -suicidal ideation.

Renal and Urinary Disorders -acute renal failure (including increased creatinine and renal insufficiency).

Skin Disorders -Stevens Johnson syndrome.

Read the entire FDA prescribing information for Namenda (Memantine HCL)

© Namenda Patient Information is supplied by Cerner Multum, Inc. and Namenda Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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