Morphine can cause bronchospasm, hypotension, and pruritus due to histamine release. Which of the following statements is true?

Morphine can cause bronchospasm, hypotension, and pruritus due to histamine release. Which of the following statements is true?

• A. Hypertension and tachycardia
• B. Hyperglycemia
• C. Pruritus alone without other symptoms
• D. Bronchospasm, hypotension, and pruritus

Answer: (D)

Morphine can cause histamine release from mast cells in a non-IgE–mediated, dose-dependent way. This histamine surge leads to three classic effects: it can cause bronchospasm by constricting bronchial smooth muscle, it can cause vasodilation with a drop in blood pressure (hypotension), and it stimulates sensory nerve endings that produce pruritus. Because these effects come from histamine acting on H1 receptors, they often occur together in sensitive patients, especially at higher doses or in those with airway reactivity. Hypertension and tachycardia don’t fit as the typical pattern here because histamine release from morphine tends to vasodilate rather than raise blood pressure, and while reflex tachycardia can occur to compensate for hypotension, hypertension itself isn’t the expected direct outcome. Hyperglycemia isn’t a primary or consistent feature of histamine release from morphine either. Pruritus can occur, but the most informative single statement is that morphine can provoke bronchospasm, hypotension, and pruritus through histamine release, capturing the main hemodynamic and cutaneous consequences.

Morphine can cause histamine release from mast cells in a non-IgE–mediated, dose-dependent way. This histamine surge leads to three classic effects: it can cause bronchospasm by constricting bronchial smooth muscle, it can cause vasodilation with a drop in blood pressure (hypotension), and it stimulates sensory nerve endings that produce pruritus. Because these effects come from histamine acting on H1 receptors, they often occur together in sensitive patients, especially at higher doses or in those with airway reactivity.

Hypertension and tachycardia don’t fit as the typical pattern here because histamine release from morphine tends to vasodilate rather than raise blood pressure, and while reflex tachycardia can occur to compensate for hypotension, hypertension itself isn’t the expected direct outcome. Hyperglycemia isn’t a primary or consistent feature of histamine release from morphine either. Pruritus can occur, but the most informative single statement is that morphine can provoke bronchospasm, hypotension, and pruritus through histamine release, capturing the main hemodynamic and cutaneous consequences.