Compared with morphine, meperidine causes which relative adverse effects to be less frequent?

Compared with morphine, meperidine causes which relative adverse effects to be less frequent?

• A. More Sedation
• B. More Nausea
• C. Similar Constipation as Morphine
• D. Less Constipation and Urinary Retention

Answer: (D)

Meperidine tends to cause fewer smooth-muscle–related side effects than morphine. The constipation and urinary retention you see with opioids come from mu-receptor activation in the gut and on the bladder. Morphine strongly stimulates those pathways, so constipation and urinary retention are more common. Meperidine still acts on mu receptors but generally has a lower impact on these particular tissues, so these two adverse effects are less frequent with it. Sedation and nausea can still occur with either drug, so they aren’t the distinguishing difference here. (Note: meperidine has other risks, like potential neurotoxic metabolites with high or prolonged use.)

Meperidine tends to cause fewer smooth-muscle–related side effects than morphine. The constipation and urinary retention you see with opioids come from mu-receptor activation in the gut and on the bladder. Morphine strongly stimulates those pathways, so constipation and urinary retention are more common. Meperidine still acts on mu receptors but generally has a lower impact on these particular tissues, so these two adverse effects are less frequent with it. Sedation and nausea can still occur with either drug, so they aren’t the distinguishing difference here. (Note: meperidine has other risks, like potential neurotoxic metabolites with high or prolonged use.)