Which medication can cause constipation as a common adverse effect?

Morphine sulfate is an opioid analgesic known for its effectiveness in relieving moderate to severe pain. However, a well-documented common adverse effect of morphine and other opioids is constipation. Opioids work by binding to the mu-opioid receptors in the central nervous system to decrease pain perception, but they also affect the gastrointestinal tract.

In the intestines, opioid receptors are present that, when activated by morphine, slow down gastrointestinal motility, reduce peristalsis, and increase the absorption of fluids. This results in harder stools and reduced bowel movements, leading to constipation.

The risk of constipation is significant with opioids, and patients often require additional medications or lifestyle modifications to help mitigate this adverse effect. In contrast, ibuprofen, antihistamines, and aspirin do not typically have constipation as a common side effect; in fact, antihistamines may occasionally cause the opposite effect by leading to diarrhea in some patients. Therefore, morphine sulfate stands out as the medication most commonly associated with constipation.