The Food and Drug Administration approved a higher dosage of a drug co-marketed by Eisai and Pfizer for Alzheimer’s disease.

Aricept (donepezil hydrochloride), which is used to treat Alzheimer’s related dementia, is the only medication approved by the FDA to treat mild, moderate, and severe Alzheimer’s-related dementia.

The drug is designed for Alzheimer’s patients to start off with 5 mg once a day, increasing dosage to 10 mg after four to six weeks.

The FDA’s decision to approve a higher dosage, 23 mg, is based on the positive results of a study that compared 10 mg Aricept with 23 mg Aricept. There were two different testing methods: The Severe Impairment Battery (SIB) which validates cognitive function; and Clinician’s Interview-Based Impression of Change Plus Caregiver Input (CIBIC+) which tracks global functioning.

The results of the study showed that 23 mg version of Aricept had significant improvement in cognitive function according to SIB test. Yet the results did not show improvement in global functioning, in CIBIC+ test.

Side effects reported during the study are relatively minor and included diarrhea, nausea, and vomiting.

There are no cure for Alzheimer’s yet, and “slowing the decline of cognitive symptoms is important at all stages of Alzheimer’s disease,” said Martin Farlow, Indiana University School of Medicine professor, and lead author of the clinical study that led to the new approval.

The higher dose version of Aricept is expected to be available in the market starting August.