Starting Dose of Memantine for Parkinson's Disease
The recommended starting dose of memantine for a patient with Parkinson's disease is 5 mg once daily, with gradual titration by 5 mg increments weekly to a target dose of 20 mg/day (given as 10 mg twice daily). 1
Dosing Schedule and Titration
Memantine should be initiated at a low dose and gradually titrated to minimize side effects:
- Week 1: 5 mg once daily
- Week 2: 10 mg daily (5 mg twice daily)
- Week 3: 15 mg daily (5 mg and 10 mg as separate doses)
- Week 4 and beyond: 20 mg daily (10 mg twice daily)
This titration schedule is based on the FDA-approved dosing guidelines for memantine 1 and has been successfully used in studies of memantine in Parkinson's disease patients 2.
Special Considerations for Parkinson's Disease Patients
While memantine is not FDA-approved specifically for Parkinson's disease, clinical research has shown it may be beneficial for patients with Parkinson's disease with dementia. A study by Zhurnal nevrologii i psikhiatrii demonstrated efficacy using the same titration schedule, starting with 5 mg daily and gradually increasing to 20 mg daily over 4 weeks 2.
Dosage Adjustments
- Renal Impairment: For patients with severe renal impairment (creatinine clearance 5-29 mL/min), reduce the target dose to 10 mg daily (5 mg twice daily) 1
- Hepatic Impairment: Administer with caution to patients with severe hepatic impairment 1
Administration Guidelines
- Memantine can be taken with or without food
- If a dose is missed, the patient should not double the next dose
- For patients who have difficulty swallowing, the extended-release capsules can be opened and sprinkled on applesauce 3
Monitoring and Follow-up
Monitor patients for:
- Cognitive improvement
- Changes in motor symptoms
- Side effects such as dizziness, headache, confusion, or hallucinations
Potential Side Effects in Parkinson's Disease
In studies of memantine in patients with Parkinson's disease dementia or dementia with Lewy bodies, common adverse events included:
These side effects may be more common in Parkinson's disease patients than in Alzheimer's disease patients, so careful monitoring during titration is essential.
Clinical Evidence in Parkinson's Disease
A double-blind, placebo-controlled study showed that memantine (20 mg/day) improved clinical global impression of change in patients with Parkinson's disease dementia 4, suggesting benefit at this dosage level. However, approximately 20% of patients may discontinue treatment due to adverse events, highlighting the importance of the gradual titration schedule 4.
By following this careful titration schedule starting at 5 mg daily, you can maximize the potential benefits while minimizing adverse effects in patients with Parkinson's disease.