TCA Monitoring — MRCPsych Paper B MCQ

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ModerateMood DisordersTCA MonitoringMRCPsych Paper B

A 38-year-old woman with treatment-resistant depression is being considered for clomipramine. She takes bendroflumethiazide, and pre-treatment blood tests reveal hypokalaemia, which is corrected before clomipramine is started. Which ECG abnormality is the principal clomipramine-related concern during treatment?

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Correct answer: D — Prolongation of the QTc interval

The correct answer is D: prolongation of the QTc interval. Clomipramine can prolong QTc and thereby increase the risk of torsades de pointes, particularly with high plasma concentrations, concomitant QT-prolonging medicines or hypokalaemia. The diuretic-associated hypokalaemia is therefore a discriminating risk factor and must be corrected before treatment. ST- and T-wave changes may occur with tricyclic antidepressants but are often non-specific and are not the principal marker of torsades risk. Bundle branch block is a possible but rare conduction disturbance rather than the key abnormality highlighted for this risk profile. Atrial fibrillation is not the characteristic clomipramine-associated ECG concern. ECG monitoring is especially indicated in patients with cardiovascular disease or other relevant risks; it is not mandated routinely for every healthy younger adult.

Reference: Viatris. Clomipramine 50 mg Capsules, Hard: Summary of Product Characteristics, sections 4.2, 4.4 and 4.5. Revised July 2026. https://www.medicines.org.uk/emc/product/2553/smpc