What is the recommended dosing schedule when starting Namenda (memantine)?

Starting Namenda (Memantine) Dosing Schedule

Begin memantine at 5 mg once daily and increase by 5 mg increments weekly until reaching the target dose of 20 mg/day (10 mg twice daily), as this gradual titration minimizes adverse effects while achieving therapeutic benefit. 1

Standard Titration Protocol

The FDA-approved dosing schedule follows a structured 4-week titration:

• Week 1: 5 mg once daily
• Week 2: 10 mg/day (5 mg twice daily)
• Week 3: 15 mg/day (5 mg and 10 mg as separate doses)
• Week 4 and beyond: 20 mg/day (10 mg twice daily) - target maintenance dose 1

The minimum interval between dose increases must be one week to allow adequate assessment of tolerability and minimize adverse effects such as dizziness, headache, confusion, and constipation. 1

Administration Considerations

• Memantine can be taken with or without food 1
• If using oral solution, do not mix with any other liquid 1
• The oral solution comes with a dosing syringe that should be used to withdraw the correct volume and slowly squirt into the corner of the patient's mouth 1

Missed Doses and Treatment Interruptions

If a single dose is missed, do not double the next dose - simply take the next scheduled dose as planned. 1

If memantine is discontinued for several days, do not restart at the previous dose. Resume at lower doses and retitrate using the standard weekly escalation schedule to avoid adverse effects. 1

Dose Adjustments for Renal Impairment

For patients with severe renal impairment (creatinine clearance 5-29 mL/min), reduce the target dose to 5 mg twice daily (10 mg/day total). 1 This recommendation is supported by pharmacokinetic data showing that patients with severe renal impairment have 115% higher drug exposure, but achieve similar steady-state concentrations with the reduced 5 mg twice daily regimen. 2

• Normal renal function or mild impairment: No dose adjustment needed - use standard 10 mg twice daily 2
• Moderate renal impairment (CrCl 30-49 mL/min): No dose adjustment needed, though exposure increases by 60% 2
• Severe renal impairment (CrCl 5-29 mL/min): Target dose 5 mg twice daily 1, 2

Hepatic Impairment

Administer memantine with caution in patients with severe hepatic impairment, though specific dose adjustments are not provided in the FDA labeling. 1

Alternative Extended-Release Formulation

An extended-release formulation (28 mg once daily) is available and may improve adherence through once-daily dosing, though it has not been directly compared to immediate-release memantine in clinical trials. 3 The ER capsules can be opened and sprinkled on applesauce for patients with swallowing difficulties. 3

Common Pitfalls to Avoid

• Do not escalate doses faster than weekly intervals - this increases risk of adverse effects without improving efficacy
• Do not restart at full dose after treatment interruption - always retitrate to minimize side effects 1
• Do not overlook renal function assessment - severe renal impairment requires dose reduction that is often missed 1, 2