According to a new study published in the journal Cognitive and Behavioral Neurology, the drug memantine and vitamin D work best together in improving cognition in Alzheimer’s patients compared to just memantine or vitamin D alone. The study was led by Dr Cedric Annweiler of the Anger University Hospital in France.
Memantine, marketed under the name Namenda, is used in Alzheimer’s to help with cognitive function. It has been shown in several randomized controlled trials to improve cognitive performance better than placebo. However, there is continued debate on whether it makes a big enough clinical impact to warrant its use.
The investigators retrospectively examined 43 patients that visited the Memory Clinic of Angers University Hospital in France for the purpose of newly diagnosed Alzheimer’s. The researchers only looked at patients who were either prescribed memantine and/or vitamin D supplements, for any reason. If patients received memantine, they took a dose titrated in 5 mg increments for 4 weeks until patients took a full dose of 20 mg/day. If a patient took vitamin D, dosages ranged from 400 and 1000 IU/day to 100,000 or 200,000 IU per month.
The Memory Clinic uses the Mini-Mental State Examination (MMSE) to asses “patients’ global cognitive performance at every visit,” among other tests. The MMSE measures five areas of cognition: orientation, registration, attention-calculation, recall and language. Scores range from 0 to 30.
Here, the researchers compared MMSE scores from patients’ first visit to their second visit after treatment with memantine, vitamin D or both. They found the following results:
- In the memantine treatment only group, the researchers found no change in MMSE scores, starting at 16.5 and dropping to 16.1. The mean length between visits was 9.6 months.
- In the vitamin D treatment only group, the researchers saw little change in MMSE scores as well, starting at 18.2 and dropping to 17.7. The mean length between visits was 6 months.
- However, in the memantine plus vitamin D treatment only group, the researchers saw a clinically significant increase in MMSE scores by 4 points, increasing from 13.8 to 17.6. The mean length between visits was also 6 months.
Thus the study found that memantine and vitamin D clinically and statistically work better together than memantine or vitamin D alone. The investigators note that:
“These results suggest that memantine and vitamin D likely interact and potentiate each other to protect neurons and improve AD symptoms.”
Study limitations include small number of participants, retrospective design, lack of serum vitamin D levels drawn and lack of placebo group.
The investigators call for further research and note that their very own double-blind randomized controlled trial administering vitamin D with memantine is already underway.