How to Start Memantine
Start memantine at 5 mg once daily and titrate by 5 mg/day weekly in divided doses to reach the target dose of 20 mg/day (10 mg twice daily). 11
Initiation and Titration Schedule
The FDA-approved titration regimen is straightforward and should be followed systematically:
- Week 1: 5 mg once daily
- Week 2: 5 mg twice daily (10 mg/day total)
- Week 3: 10 mg in morning + 5 mg in evening (15 mg/day total)
- Week 4 onward: 10 mg twice daily (20 mg/day target dose)
This weekly escalation by 5 mg/day increments in divided doses minimizes side effects while achieving therapeutic dosing within one month 11.
Approved Indications
Memantine is indicated for moderate to severe Alzheimer's disease, demonstrated in pivotal trials showing significant improvements in cognition (measured by SIB) and daily function (measured by ADCS-ADL) 11. The 2020 Canadian Consensus Conference confirms memantine use for AD, Parkinson's disease dementia (PDD), dementia with Lewy bodies (DLB), and vascular dementia (VD) 2.
The evidence base is strongest for:
- Moderate to severe AD (MMSE scores 3-14)
- Patients already on stable cholinesterase inhibitor therapy (combination therapy showed additional benefit) 11
Critical Dosing Considerations
Renal dose adjustment is essential but frequently overlooked. A retrospective study found that 60% of patients requiring renal dose adjustment were not receiving appropriate doses 3. While specific adjustment parameters aren't detailed in the provided evidence, this represents a common prescribing error that compromises both safety and efficacy.
Monitoring for Response
Assess treatment response after at least 12 weeks of therapy. The Canadian guidelines recommend considering discontinuation only after >12 months if 2:
- Clinically meaningful worsening occurred over the past 6 months
- No benefit was ever observed (no improvement, stabilization, or decreased decline rate)
- Severe/end-stage dementia has developed
- Intolerable side effects emerge (confusion, dizziness, falls)
Do not discontinue memantine during active psychotic symptoms, agitation, or aggression unless these symptoms worsened after starting the medication 2.
Safety Profile
Memantine demonstrated favorable tolerability in clinical trials. Common side effects are generally mild and manageable. The gradual weekly titration schedule specifically minimizes adverse effects during dose escalation 11.
What NOT to Do
- Do not use memantine for mild cognitive impairment - guidelines explicitly recommend deprescribing in this population 2
- Do not use for unapproved indications (e.g., frontotemporal dementia, other neurodegenerative conditions) - should be discontinued in these cases 2
- Do not skip the titration schedule - jumping directly to 20 mg/day increases side effect risk
- Do not forget to check renal function before prescribing and adjust accordingly
If Doses Are Missed
If a patient misses a single dose, do not double the next dose - simply resume the regular schedule. If several days of doses are missed, do not resume at the previous dose without consulting the prescriber, as re-titration may be necessary 1.