(HealthDay News) — Dextromethorphan combined with sitagliptin shows potential for treatment of type 2 diabetes mellitus, according to a study published online September 12 in Diabetes, Obesity and Metabolism.

Jan Marquard, MD, from Heinrich Heine University in Germany, and colleagues examined the blood-glucose-lowering effects of 30, 60, and 90mg dextromethorphan as well as 100mg sitagliptin alone vs. combinations of dextromethorphan and sitagliptin during an oral glucose tolerance test (OGTT). Participants consisted of 20 males with type 2 diabetes mellitus.

The researchers found that the strongest effect in the OGTT was seen with the combination of 60mg dextromethorphan plus 100mg sitagliptin. Maximum blood glucose concentrations were lowered with this combination. In addition the baseline-adjusted area under the curve of serum insulin concentrations was increased in the first 30 minutes of the OGTT to a significantly larger extent than with 100mg sitagliptin alone (P<0.05) or placebo (P<0.001). All study drugs, alone or in combination, were tolerated, with no evidence of serious adverse events or hypoglycemia.

“Long-term clinical trials are now warranted to investigate the potential of the combination of 30 or 60mg dextromethorphan and dipeptidyl peptidase-4 inhibitors in the treatment of individuals with type 2 diabetes mellitus, in particular since preclinical studies revealed beta cell protective properties of dextromethorphan,” the authors write.

Three study authors are pursuing a patent titled “Morphinan-derivatives for treating diabetes and related disorders.”

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