Acarbose (INN)[1][2] is an anti-diabetic drug used to treat diabetes mellitus type 2 and, in some countries, prediabetes.

It works by inhibiting alpha glucosidase, an intestinal enzyme that releases glucose from larger carbohydrates such as starch and sucrose.

[3] Acarbose is cheap and popular in China, but not in the U.S. One physician explains that use in the U.S. is limited because it is not potent enough to justify the side effects of diarrhea and flatulence.

"[5] A possible explanation for the differing opinions is an observation that acarbose is significantly more effective in patients eating a relatively high-starch Eastern diet.

[8] It was found that acarbose reduced the incidence of diabetes mellitus type 2 when compared to placebo, however there was no conclusive evidence that acarbose, when compared to diet and exercise, metformin, placebo, or no intervention, improved all-cause mortality, reduced or increased risk of cardiovascular mortality, serious or non-serious adverse events, non-fatal stroke, congestive heart failure, or non-fatal myocardial infarction.

One study found that gastrointestinal side effects decreased significantly (from 50% to 15%) over 24 weeks, even on constant dosing.

[12] A 2016 meta-analysis confirms that alpha-glucosidase inhibitors, including acarbose, have a statistically significant link to elevated transaminase levels.

[17] Human enzymes do transform acarbose: the pancreatic alpha-amylase is able to perform a rearrangement reaction, moving the glucose unit in the "tail" maltose to the "head" of the molecule.

Analog drugs with the "tail" glucose removed or flipped to an α(1-6) linkage resist this transformation.

[21] The molecular modeling showed the interaction between gut bacterial acarbose degrading glucosidase and human α-amylase.