A patient requires increasing morphine doses to manage chronic pain following surgery. Which mechanism primarily explains the reduced analgesic effect over time?

💡 Explanation

Tolerance develops as the body adapts to chronic morphine exposure, causing decreased opioid receptor sensitivity. Because of this reduced sensitivity, a higher dose is needed to achieve the same analgesic effect. Therefore, decreased receptor sensitivity, rather than changes in receptor expression or permeability, explains the phenomenon.

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