From the Guidelines
The maximum recommended dose of Namenda (memantine) is 28 mg once daily for the extended-release formulation or 10 mg twice daily (20 mg total per day) for the immediate-release formulation. Patients typically start at a lower dose and gradually increase to the maximum dose over several weeks to minimize side effects. For the extended-release capsules, patients usually begin with 7 mg once daily and increase weekly by 7 mg until reaching the target dose of 28 mg daily. For immediate-release tablets, the typical titration schedule starts with 5 mg once daily, increasing to 5 mg twice daily, then 10 mg in the morning and 5 mg in the evening, before reaching the full 10 mg twice daily dose. Patients with severe renal impairment (creatinine clearance 5-29 mL/min) should not exceed 14 mg daily for extended-release or 5 mg twice daily for immediate-release. Memantine works as an NMDA receptor antagonist that regulates glutamate activity in the brain, which is believed to contribute to its therapeutic effect in moderate to severe Alzheimer's disease by reducing excitotoxicity while preserving normal neurotransmission 1.
Some key points to consider when prescribing memantine include:
- The dosage of memantine used in most studies was 20 mg/d, with some variation in duration and population studied 1.
- Memantine has been shown to result in statistically significant, but not clinically important, improvement on the ADAS-cog scale in cognition for individuals with mild to moderate vascular dementia and mild to moderate Alzheimer disease 1.
- Patients with moderate to severe Alzheimer disease have statistically significantly improved on the SIB scale when treated with memantine 1.
- The withdrawal rates related to adverse effects varied from 9% to 12% in the treatment group, including nausea, dizziness, diarrhea, and agitation 1.
Overall, the evidence suggests that memantine is a safe and effective treatment for moderate to severe Alzheimer's disease, with a maximum recommended dose of 28 mg once daily for the extended-release formulation or 10 mg twice daily (20 mg total per day) for the immediate-release formulation.
From the FDA Drug Label
The maximum dose is 28 mg/10 mg once daily The maximum recommended dose of Namenda (memantine) is 28 mg once daily, in combination with 10 mg of donepezil hydrochloride 2.
From the Research
Maximum Recommended Dose of Namenda (Memantine)
- The maximum recommended dose of Namenda (memantine) is 20 mg per day for the immediate-release formulation, administered orally twice daily 3.
- For patients with severe renal impairment, a target dose of 5 mg twice daily is recommended 4.
- An extended-release formulation of memantine is also available, with a recommended dose of 28 mg once daily 3, 5.
- Studies have shown that memantine is well-tolerated and effective in treating moderate to severe Alzheimer's disease, with benefits on cognition, mood, and behavior 6, 7.
- However, the clinical implications of the higher total daily dosage provided by the extended-release formulation are unclear, and further studies are needed to determine its effectiveness compared to the immediate-release formulation 3, 5.