Memantine (Namenda)
Glutamate antagonist (NMDA)
- Alzheimer’s Dementia1 (also Lewy body, Parkinson’s Dementias)
- Trichotillomania1 and skin picking
- OCD3
- Alcohol use disorder (augments naltrexone).3 May treat depression in alcohol use disorder3
- Bipolar depression and mixed features4
- Autism (social functioning)2
Features
Dosing
Instant release: Start 5 mg daily, raise by 5 mg every 3-7 days toward target of 10 mg bid.
Extended release: Start 7 mg daily, raise by 7 mg every 3-7 days toward target of 28 mg qd (which equals 20 mg of instant release).
The dose is the same for all uses, but for manic symptoms go up to 50 mg/day.
Management
Memantine is approved for moderate to severe dementia. For mid dementia, prefer donepezil, although for moderate to severe the two are often combined together (and approved that way as Namzaric.
In psychiatry, the main use is for trichotillomania, where it had a large effect size (and there are no other meds except NAC for this). It may treat OCD and alcohol use, but half of those trials were negative, and the bipolar studies are very small.
Autism: 10 mg bid (but some RCTs were negative so not clearly effective).
TOLERABILITY: Dizzy, headache, sedation.
RISKS: Confusion, hallucinations.
EMR Text
Dementia
Memantine use based on FDA approval in dementia.
Memantine side effects reviewed with patient.
Trichotillomania
Memantine use based on a randomized controlled trials in trichotillomania and skin picking (Grant JE et al, Am J Psychiatry. 2023;180(5):348-356).
Memantine side effects reviewed with patient.
Alcohol use disorder
Memantine use based on randomized trials in alcohol use disorder, where it improved depression and augmented other therapies for alcohol (Krishnan-Sarin S et al, Neuropsychopharmacology. 2020;45(2):319-326; Muhonen LH et al, J Clin Psychiatry. 2008;69(3):392-399).
Memantine side effects reviewed with patient.
OCD
Memantine use based on randomized controlled trials in OCD (Zhang W et a, J Coll Physicians Surg Pak. 2025;35(4):494-502).
Memantine side effects reviewed with patient.
Autism
Memantine use based on randomized controlled trial where it improved social functioning in autism (Joshi G et al, JAMA Netw Open. 2025;8(10):e2534927).
Memantine side effects reviewed with patient.