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Question 451
Pharmacology → General
Classification
Question
SSBAQuestion Header
A patient taking amitriptyline develops dry mouth, urinary retention and palpitations. Which additional serious complication is associated with this drug class?
Question Stem
Select the single best answer.
Options
A
Profound hypoglycaemia from beta-cell stimulation
B
Severe rebound hypertension after abrupt withdrawal
C
Arrhythmias and heart block
D
Premature closure of the ductus arteriosus
E
Hyperkalaemia due to epithelial sodium-channel inhibition
Explanation
Tricyclic antidepressants produce prominent anticholinergic adverse effects including dry mouth, constipation, urinary retention, blurred vision and palpitations. Tricyclic antidepressants may also cause serious arrhythmias and heart block, particularly with amitriptyline, and have a relatively low safety margin in overdose.
Option Validity
A) Hypoglycaemia is associated with glucose-lowering drugs such as sulphonylureas rather than tricyclic antidepressant toxicity.
B) Severe rebound hypertension following abrupt withdrawal is described for clonidine.
D) Premature ductal closure is a concern associated with NSAID exposure in late pregnancy.
E) Potassium retention due to distal sodium-channel inhibition relates to potassium-sparing diuretics.
Further Reading
Saxena R. Textbook for MRCOG-1. Chapter 12: Pharmacology. Antidepressant Drugs, pp.346–347.