Bisacodyl interacts with milk through what mechanism?

Bisacodyl interacts with milk through what mechanism?

• A. Complexation
• B. Adsorption
• C. Alteration of pH
• D. Alteration of motility

Answer: (C)

The key idea is that this drug is designed to release its active form based on the pH of the surrounding environment. Bisacodyl is enteric-coated so it survives the acidic stomach and dissolves in the more alkaline conditions of the small intestine. Milk can buffer stomach acid, raising the gastric pH. That change in pH can cause the enteric coating to dissolve earlier than intended, altering where and how quickly the drug is released. So the interaction with milk happens through alteration of pH. Complexation, adsorption, or changing gut motility don’t explain this food–drug interaction in the same way. To avoid this effect, take bisacodyl with water rather than milk.

The key idea is that this drug is designed to release its active form based on the pH of the surrounding environment. Bisacodyl is enteric-coated so it survives the acidic stomach and dissolves in the more alkaline conditions of the small intestine. Milk can buffer stomach acid, raising the gastric pH. That change in pH can cause the enteric coating to dissolve earlier than intended, altering where and how quickly the drug is released. So the interaction with milk happens through alteration of pH. Complexation, adsorption, or changing gut motility don’t explain this food–drug interaction in the same way. To avoid this effect, take bisacodyl with water rather than milk.