Morphine Histamine Release — FRCA Primary MCQ

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EasyPharmacology - AnalgesicsMorphine Histamine ReleaseFRCA Primary

Morphine differs from fentanyl in that morphine:

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Correct answer: E — Causes more histamine release

Morphine causes significant histamine release leading to hypotension / bronchospasm / and urticaria. Fentanyl causes negligible histamine release. Morphine is less lipid-soluble (slower onset) / has a longer duration / produces active metabolites (M6G / M3G) / and causes respiratory depression (as do all mu-agonists).

Reference: Peck Hill Williams 2014 Pharmacology for Anaesthesia and Intensive Care