Which is an adverse effect of morphine?

Which is an adverse effect of morphine?

• A. Respiratory depression
• B. Miosis
• C. Coma
• D. Hypertension

Answer: (A)

Opioids like morphine most notably depress the brainstem centers that regulate breathing, making respiratory depression the key dose-limiting adverse effect. Activation of mu receptors in the CNS reduces the sensitivity of the respiratory center to rising CO2, leading to slower, shallower breathing and potential hypoventilation or arrest if the dose is high or when combined with other depressants. This risk is central to how morphine is used and monitored in clinical practice. Miosis, a pinpoint pupil response, is a classic opioid effect but not the primary adverse effect that drives safety concerns in most scenarios. Hypertension is not typical for opioids (they more commonly cause hypotension). Coma can occur with overdose, but the question targets the most characteristic and clinically significant adverse effect, which is respiratory depression.

Opioids like morphine most notably depress the brainstem centers that regulate breathing, making respiratory depression the key dose-limiting adverse effect. Activation of mu receptors in the CNS reduces the sensitivity of the respiratory center to rising CO2, leading to slower, shallower breathing and potential hypoventilation or arrest if the dose is high or when combined with other depressants. This risk is central to how morphine is used and monitored in clinical practice.

Miosis, a pinpoint pupil response, is a classic opioid effect but not the primary adverse effect that drives safety concerns in most scenarios. Hypertension is not typical for opioids (they more commonly cause hypotension). Coma can occur with overdose, but the question targets the most characteristic and clinically significant adverse effect, which is respiratory depression.