SBA — Single Best Answer · Review
Question 453
Pharmacology → General
Classification
Question
SSBAQuestion Header
After morphine administration, a patient develops hypotension and bronchospasm without evidence of direct myocardial depression. Which mechanism best links these two adverse effects?
Question Stem
Select the single best answer.
Options
A
Histamine release
B
Direct beta-2 receptor blockade
C
Inhibition of renal prostaglandin synthesis
D
Presynaptic alpha-2 receptor stimulation
E
Na-K-2Cl cotransporter inhibition
Explanation
Morphine does not directly depress the myocardium, although it may cause bradycardia. It can reduce systemic vascular resistance and cause hypotension partly through histamine release; the same histamine release may also produce bronchospasm.
Option Validity
B) Morphine is an opioid and its described hypotensive and bronchospastic effects are not attributed to beta-2 receptor blockade.
C) Inhibition of renal prostaglandin synthesis is associated with NSAIDs.
D) Presynaptic alpha-2 stimulation is the central mechanism described for clonidine.
E) Na-K-2Cl cotransporter inhibition is the mechanism of loop diuretics.
Further Reading
Saxena R. Textbook for MRCOG-1. Chapter 12: Pharmacology. Analgesics, p.347.