Antidepressants and Glaucoma — MRCPsych Paper B MCQ

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EasyMood DisordersAntidepressants and GlaucomaMRCPsych Paper B

A 60-year-old man with a major depressive episode has persistent anatomically narrow anterior chamber angles and remains at high risk of recurrent acute angle-closure glaucoma. If an antidepressant is required, which class should be avoided where possible because its antimuscarinic effect can cause mydriasis and precipitate an acute attack?

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Correct answer: D — Tricyclic antidepressants

Tricyclic antidepressants, particularly strongly antimuscarinic agents such as amitriptyline, should be avoided where possible in a patient who remains at high risk of angle closure. Antimuscarinic pupillary dilatation can obstruct an already narrow drainage angle, rapidly increase intraocular pressure and precipitate acute angle-closure glaucoma. The amitriptyline SmPC specifically warns that acute glaucoma may be provoked in patients with shallow anterior chambers and narrow angles. SSRIs and SNRIs are not completely risk-free: sertraline and venlafaxine SmPCs also warn about mydriasis and advise caution or monitoring in susceptible patients. However, they do not have the characteristic antimuscarinic burden of TCAs and are not the best answer to the stated mechanism. Antidepressant selection should be individualised with ophthalmological advice.

Reference: Electronic Medicines Compendium, Amitriptyline 50 mg Film-Coated Tablets, Summary of Product Characteristics, sections 4.4 and 4.8, revised 2025. https://www.medicines.org.uk/emc/product/10851/smpc