Which two medications could be causing painful abdominal bloating when taken together?

Metformin and Acarbose can both affect the gastrointestinal system, and when taken together, they may exacerbate side effects such as painful abdominal bloating.

Metformin is known for its gastrointestinal side effects, including bloating, diarrhea, and abdominal discomfort, especially when initiating therapy or during dose increases. Acarbose, an alpha-glucosidase inhibitor, works by delaying the digestion and absorption of carbohydrates in the intestines. This mechanism can lead to increased gas production due to fermentation of unabsorbed carbohydrates, contributing to bloating and discomfort.

When these two medications are used in combination, the likelihood of experiencing gastrointestinal symptoms can increase due to their overlapping effects on the digestive system. Acarbose's action of preventing carbohydrate absorption, combined with Metformin's gastrointestinal side effects, creates a scenario where the patient is more prone to experience painful abdominal bloating than they might with either medication alone or in combination with different medications.

Other combinations presented in the choices involve medications that do not typically cause significant gastrointestinal side effects when used together, making them less likely to lead to bloating. Therefore, Metformin and Acarbose are indeed the most plausible pair for causing this specific side effect when taken together.