Makers of the Alzheimer’s drug Aricept released a higher dosage version of the medication despite concerns about side effects and reduced efficacy, a study reports.

Aricept, which was developed by the Japanese drugmaker Eisai and marketed by Pfizer in the United States, was set to lose its patent protection in November 2010, the New York Times reported. Eisai applied for a 23-milligram version of the drug — marketed as Aricept 23 — which would eliminate the need for patients or physicians to combine existing 5- and 10-milligram doses. Although the Aricept 23 caused more nausea and vomiting according to results of a clinical trial released this month, the drug was approved by the Food and Drug Administration. That drew the ire of some physicians.

“Rarely do we see such a dangerous difference between what pretty much everyone in the neurological division thought and what its leader thought,” Sidney M. Wolfe, M.D., director of Public Citizen’s Health Research Group, told the New York Times.

Despite these concerns over potentially high dosages, British researchers also said this month that Alzheimer’s drugs, including Aricept, are underused.