What adverse reaction is associated with bismuth subsalicylate?

Bismuth subsalicylate is primarily used to treat conditions like diarrhea and to relieve upset stomach. One of the notable adverse reactions associated with its use is constipation. Bismuth compounds can slow down the digestive process in some individuals, leading to decreased bowel movements. This effect is particularly significant in patients who may already have a propensity for sluggish bowel activity.

The reason constipation is the correct answer is that it aligns with the pharmacological action of bismuth subsalicylate, which involves binding to gastrointestinal secretions and reducing gut motility as part of its mechanism to control diarrhea. The potential for this medication to cause constipation is well-documented and something healthcare providers monitor when prescribing it.

Other adverse reactions, such as weight gain, hypoglycemia, or nausea, are not typically associated with bismuth subsalicylate. While nausea may occur in some instances as a general gastrointestinal response, it is not the most significant or prevalent reaction linked directly to this medication. Thus, the focus on constipation as an adverse reaction is warranted due to its direct relationship with the drug's digestive effects.