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Donepezil / memantine Side Effects

In Summary

Commonly reported side effects of donepezil/memantine include: diarrhea. Other side effects include: dizziness, nausea, vomiting, anorexia, and ecchymoses. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to donepezil / memantine: oral capsule delayed release, oral capsule extended release

In addition to its needed effects, some unwanted effects may be caused by donepezil / memantine. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking donepezil / memantine:

Incidence not known:
  • Bloody or black, tarry stools
  • chest pain or discomfort
  • decreased urination
  • lightheadedness, dizziness, or fainting
  • pain in the lower abdomen, groin, upper back or sides
  • seizures
  • severe stomach pain
  • slow or irregular heartbeat
  • sweating
  • trouble breathing
  • unusual tiredness
  • vomiting of blood or material that looks like coffee grounds

Minor Side Effects

Some of the side effects that can occur with donepezil / memantine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Incidence not known:
  • Constipation
  • decreased appetite
  • diarrhea
  • nausea
  • vomiting

For Healthcare Professionals

Applies to donepezil / memantine: oral capsule extended release, oral kit


Common (1% to 10%): Hypertension, hypotension
Postmarketing reports: Congestive cardiac failure

Common (1% to 10%): Hypertension, hemorrhage, syncope
Postmarketing reports: Heart block (all types)[Ref]

Nervous system

Common (1% to 10%): Headache, dizziness, somnolence

Common (1% to 10%): Headache, dizziness, somnolence
Postmarketing reports: Convulsions, neuroleptic malignant syndrome[Ref]


Common (1% to 10%): Diarrhea, constipation, abdominal pain, vomiting
Postmarketing reports: Pancreatitis

Very common (10% or more): Diarrhea (10%)
Common (1% to 10%): Vomiting, anorexia, nausea
Postmarketing reports: Abdominal pain, pancreatitis[Ref]


Common (1% to 10%): Influenza[Ref]


The most common adverse reactions in patients receiving memantine ER were headache, diarrhea, and dizziness. The most common adverse reactions in patients receiving donepezil were diarrhea, anorexia, vomiting, nausea, and ecchymosis.[Ref]


Postmarketing reports: Stevens Johnson Syndrome

Common (1% to 10%): Eczema
Postmarketing reports: Rash[Ref]


Postmarketing reports: Agranulocytosis, leukopenia (including neutropenia), pancytopenia, thrombocytopenia, thrombotic thrombocytopenic purpura

Common (1% to 10%): Ecchymosis
Postmarketing reports: Hemolytic anemia[Ref]


Postmarketing reports: Hepatitis

Postmarketing reports: Cholecystitis, hepatitis[Ref]


Common (1% to 10%): Increased creatinine phosphokinase, dehydration, hyperlipidemia
Postmarketing reports: Hyponatremia[Ref]


Common (1% to 10%): Back pain

Common (1% to 10%): Back pain[Ref]


Common (1% to 10%): Increased weight

Very common (10% or more): Accident (13%), infection (11%)
Common (1% to 10%): Fever, pain, chest pain[Ref]


Common (1% to 10%): Anxiety, depression, aggression
Postmarketing reports: Suicidal ideation

Common (1% to 10%): Insomnia, nervousness, hallucinations, hostility, depression, confusion, emotional lability, personality disorder
Postmarketing reports: Agitation, confusion, hallucinations[Ref]


Common (1% to 10%): Urinary incontinence
Postmarketing reports: Acute renal failure

Common (1% to 10%): Urinary incontinence[Ref]


1. "Product Information. Namzaric (donepezil-memantine)." Forest Pharmaceuticals, St. Louis, MO.

Not all side effects for donepezil / memantine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.