Memantine: uses, dosing, side effects & brands
Memantine is a n-methyl-d-aspartate receptor antagonist sold in the U.S. under 3 brand and generic names, for alzheimer disease. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- N-Methyl-D-Aspartate Receptor Antagonist
- Treats (across its forms)
- Alzheimer Disease
- Available as
- Kit · Tablet · Capsule, extended release
- Sold as
- 3 products — Namenda, Namenda XR and Memantine Hydrochloride
- Prescription?
- Prescription only
- Generic available?
- Yes
- Half-life
- about 60 to 80 hours
- What the pharmacy pays
- about $2 for a 30-count supply — not your price
How Namenda is dosed
From the FDA label for Namenda (application NDA021487). Other memantine products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The recommended starting dose of memantine hydrochloride tablets is 5 mg once daily. The dose should be increased in 5 mg increments to 10 mg/day (5 mg twice daily), 15 mg/day (5 mg and 10 mg as separate doses), and 20 mg/day (10 mg twice daily). The minimum recommended interval between dose increases is one week. The dosage shown to be effective in controlled clinical trials is 20 mg/day. Memantine hydrochloride tablets can be taken with or without food. If a patient misses a single dose of memantine hydrochloride, that patient should not double up on the next dose. The next dose should be taken as scheduled. If a patient fails to take memantine hydrochloride tablets for several days, dosing may need to be resumed at lower doses and retitrated as described above. Specific Populations Renal Impairment A target dose of 5 mg twice daily is recommended in patients with severe renal impairment (creatinine clearance of 5 – 29 mL/min based on the Cockcroft-Gault equation). Hepatic Impairment Memantine hydrochloride tablets should be administered with caution to patients with severe hepatic impairment [see Clinical Pharmacology ( 12.3 )] . May be taken with or without food. ( 2 ) Initial dose is 5 mg once daily. Increase dose in 5 mg increments to a maintenance dose of 10 mg twice daily. A minimum of 1 week of treatment with the previous dose should be observed before increasing the…
Everything below is the FDA label for Namenda (kit, tablet). Memantine is also sold as capsule, extended release, and those are different medicines to take — follow the label for the one you were prescribed.
Namenda side effects
Most 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. Most Common Adverse Reactions In double-blind…
Who shouldn’t take Namenda
Memantine hydrochloride tablets are contraindicated in patients with known hypersensitivity to memantine hydrochloride or to any excipients used in the formulation. Memantine hydrochloride tablets are contraindicated in patients with known hypersensitivity to memantine hydrochloride or to any excipients used in the formulation. ( 4 )
Namenda drug interactions
7. 1 Drugs that Make t he Urine Alkaline The clearance of memantine was reduced by about 80% under alkaline urine conditions at pH 8. Therefore, alterations of urine pH towards the alkaline condition may lead to an accumulation of the drug with a possible increase in adverse effects. Urine pH is altered by diet, drugs (e.g. carbonic anhydrase inhibitors, sodium bicarbonate) and clinical state of the patient (e.g. renal tubular acidosis or severe infections of the urinary tract). Hence, memantine should be used with caution under these conditions. 7.2 Use with Other N-methyl-D-aspartate (NMDA) Antagonists The combined use of memantine hydrochloride with other NMDA antagonists (amantadine, ketamine, and dextromethorphan) has not been systematically evaluated and such use should be approached with caution.
Every memantine product we track (3)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 72/100 | Prescription | Kit | Generic | $2 | View → | |
| 2 | 72/100 | Prescription | Capsule | Generic | $2 | View → | |
| 3 | Not yet rated | Prescription | Capsule | Generic | $2 | View → |
What memantine pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
Combination products containing memantine
A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.
Memantine recalls
From the FDA Enforcement database. A recall covers specific lots — not the drug as a whole.
Can you crush or split memantine?
At least one memantineproduct is labelled to be swallowed whole — crushing an extended-release tablet releases the whole day’s dose at once. Which applies depends on the form you were given.
What each memantine label says about crushing, splitting and chewingHow long memantine keeps
No memantine label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Does memantine expire? The in-use limits and storage rules from its labelsWhat people report to the FDA about memantine
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 3,102 reports naming memantine, and the FDA flagged 89% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- fall225 reports
- asthenia160 reports
- fatigue153 reports
- confusional state136 reports
- somnolence125 reports
- nausea118 reports
- pneumonia110 reports
- dizziness101 reports
Read these as a signal, not a rate. A report does not mean memantine caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
How long memantine stays in your system
The elimination half-life of memantine is about 60 to 80 hours. This is the terminal elimination half-life the label reports for memantine itself; the label gives it as a range and does not narrow it further. Memantine is not a prodrug, and it has no long-lasting active metabolite to worry about: roughly 48% of a dose is excreted unchanged in urine, and the label describes the three metabolites it does form (the N-glucuronide conjugate, 6-hydroxy memantine, and 1-nitroso-deaminated memantine) as possessing only minimal NMDA-receptor antagonistic activity. Populations the label names: in older adults, the label states that the pharmacokinetics in young and elderly subjects are similar. In kidney impairment, the terminal elimination half-life is longer — increased by about 18% in mild, 41% in moderate, and 95% (roughly double) in severe renal impairment. In moderate liver impairment (Child-Pugh B), the terminal half-life increased by about 16%, with overall exposure unchanged; severe hepatic impairment has not been evaluated.
DailyMed — MEMANTINE HYDROCHLORIDE (memantine tablet, film coated), §12.3 Pharmacokinetics ↗Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Related calculators
Frequently asked questions
What is Namenda?
Namenda (Memantine Hydrochloride) is a n-methyl-d-aspartate receptor antagonist used to treat Alzheimer Disease.
What kind of drug is memantine?
The FDA classifies memantine as a n-methyl-d-aspartate receptor antagonist. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
How long does memantine stay in your system?
The elimination half-life of memantine is about 60 to 80 hours — that is how long the body takes to clear half of a dose. This is the terminal elimination half-life the label reports for memantine itself; the label gives it as a range and does not narrow it further. Memantine is not a prodrug, and it has no long-lasting active metabolite to worry about: roughly 48% of a dose is excreted unchanged in urine, and the label describes the three metabolites it does form (the N-glucuronide conjugate, 6-hydroxy memantine, and 1-nitroso-deaminated memantine) as possessing only minimal NMDA-receptor antagonistic activity. Populations the label names: in older adults, the label states that the pharmacokinetics in young and elderly subjects are similar. In kidney impairment, the terminal elimination half-life is longer — increased by about 18% in mild, 41% in moderate, and 95% (roughly double) in severe renal impairment. In moderate liver impairment (Child-Pugh B), the terminal half-life increased by about 16%, with overall exposure unchanged; severe hepatic impairment has not been evaluated. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.
Can you take memantine with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run memantine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is memantine sold under?
We track 3 memantine-containing products in the U.S.: Namenda, Namenda XR and Memantine Hydrochloride. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does memantine come in?
Across the brands we track, memantine is currently marketed as kit, tablet and capsule, extended release, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic memantine?
Yes. Our catalog lists 1 generic memantine product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Has memantine been recalled?
The FDA's Enforcement database lists 1 recall record whose product description mentions memantine. The most recent: Memantine Hydrochloride Extended-Release (Mar 24, 2026). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.
Cite this page
- APA
- pharmaranks. (2026, July 24). Memantine: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/memantine
- MLA
- “Memantine: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/memantine.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for memantine on DailyMed (NIH) ↗.