Which is a common adverse effect of an opioid analgesic?

Which is a common adverse effect of an opioid analgesic?

• A. Constipation
• B. Nausea
• C. Sedation
• D. Dizziness

Answer: (A)

Opioid analgesics commonly slow the gut. They activate μ-opioid receptors in the GI tract, which reduces intestinal motility and increases water absorption from the stool. The result is slower transit and drier, harder stools—constipation. This effect is especially persistent with continued opioid use and is seen across many opioid types, making it a hallmark adverse effect. Nausea, sedation, and dizziness can occur with opioids, especially when starting therapy or at higher doses, but they are not as universally and consistently experienced as constipation.

Opioid analgesics commonly slow the gut. They activate μ-opioid receptors in the GI tract, which reduces intestinal motility and increases water absorption from the stool. The result is slower transit and drier, harder stools—constipation. This effect is especially persistent with continued opioid use and is seen across many opioid types, making it a hallmark adverse effect.

Nausea, sedation, and dizziness can occur with opioids, especially when starting therapy or at higher doses, but they are not as universally and consistently experienced as constipation.