What the label lists and what reports show
Memantine side effects
Memantine's FDA label: “Most common adverse reactions (≥ 5 % and greater than placebo) are dizziness, headache, confusion and constipation.” FAERS holds 13,605 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is fall (996 reports).
- Generic listed
Check it at the source: the memantine FDA label on DailyMed (effective November 1, 2018, Actavis Pharma, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of m emantine hydrochloride tablets ?Memantine hydrochloride tablets may cause side effects, including: The most common side effects of memantine hydrochloride tablets include: dizziness headache confusion constipation These are not all the possible side effects of memantine hydrochloride tablets. For more information, ask your doctor or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Source: FDA drug label, NDA021487 (Abbvie), as published by Actavis Pharma, Inc., effective November 1, 2018 (SPL set 72973b46-f307-4a9e-8fb1-ad2cbccfd736), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥ 5 % and greater than placebo) are dizziness, headache, confusion and constipation.
Table 1: Adverse Reactions Reported in Controlled Clinical Trials in at Least 2% of Patients Receiving Memantine Hydrochloride and at a Higher Frequency than Placebo-treated Patients
| Adverse Reaction | Placebo (N = 922) % | Memantine H ydrochloride (N = 940) % |
|---|---|---|
| Fatigue | 1 | 2 |
| Pain | 1 | 3 |
| Hypertension | 2 | 4 |
| Dizziness | 5 | 7 |
| Headache | 3 | 6 |
| Constipation | 3 | 5 |
| Vomiting | 2 | 3 |
| Back pain | 2 | 3 |
| Confusion | 5 | 6 |
| Somnolence | 2 | 3 |
| Hallucination | 2 | 3 |
| Coughing | 3 | 4 |
| Dyspnea | 1 | 2 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedMost common adverse reactions (≥ 5 % and greater than placebo) are dizziness, headache, confusion and constipation. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Actavis at 1-800-272-5525 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Memantine hydrochloride 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 memantine hydrochloride 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 memantine hydrochloride up to 20 mg/day, the likelihood of discontinuation because of an adverse reaction was the same in the memantine hydrochloride 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 memantine hydrochloride-treated patients and at a rate greater than placebo.
Source: FDA drug label, NDA021487 (Abbvie), as published by Actavis Pharma, Inc., effective November 1, 2018 (SPL set 72973b46-f307-4a9e-8fb1-ad2cbccfd736), via openFDA; the full label on DailyMed
What do FAERS reports show?
13,605 reports list memantine among the medicines taken, each a report of something that happened, not proof the medicine caused it; 2,094 are coded as a death and 5,513 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 18 reactions below, 7 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Memantine: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions