Serotonin–Norepinephrine Reuptake Inhibitor Contributing To Confusion Post Right Unilateral Brief-Pulse Electroconvulsive Therapy

To the Editor

Patients receiving electroconvulsive therapy (ECT) while on an serotonin–norepinephrine reuptake inhibitor (SNRI) can occasionally become confused (Sackheim et al., 2009).

Our case is of a 42-year-old nurse and mother of three who presented to hospital twice in the context of significant drug overdose. She developed depressive symptoms with ruminating thoughts of suicide, which included her crashing her car into a tree or injecting herself with potassium chloride, culminating in her pilot admission. Given her poor response to antidepressants, ECT was considered.

The patient’s dose of Desvenlafaxine was increased to 150 mg from 100 mg and right unilateral (RUL) Brief-pulse ECT was initiated. Her mood improved significantly; however, after her sixth ECT session, she was confused and experienced periods of derealisation and depersonalization. This recurred after her seventh ECT session, following which ECT ceased. She continued on Desvenlafaxine and her cognitive functions improved.

Three weeks post discharge, she overdosed on all her prescription medications and was readmitted. She received six RUL Ultrabrief-pulse ECT sessions in the absence of Desvenlafaxine, and no cognitive problems were noted. At the completion of ECT, the patient was commenced on Duloxetine and Lithium, as an adjunct, as recommended by evidence-based research.

A prospective study done by Sackheim et al. (2009) found that cognitive adverse effects of Brief-pulse ECT were unchanged or worsened by Venlafaxine. Phase 1 of The PRIDE Study demonstrated that RUL Ultrabrief-pulse ECT, combined with Venlafaxine, was a rapidly acting and highly effective treatment option for depressed geriatric patients (Kellner et al., 2016). ECT is understood to cause significant downregulation of β₂ adrenergic receptors, and multiple animal studies have demonstrated enhancement of noradrenergic transmission ensuing ECT ameliorates adverse cognitive outcomes. It is thought that adrenergic effects of Venlafaxine are triggered at higher dosage levels than attained during acute ECT phase; thus, the assumption that pharmacological actions of Venlafaxine mimic a selective serotonin reuptake inhibitor (SSRI). Sackheim et al. (2009) study implies not to administer SNRI concurrently with Brief-pulse ECT. However, The PRIDE Study supports concurrent use of Venlafaxine with Ultrabrief-pulse ECT to achieve better results. Our patient who received combination Desvenlafaxine and Brief-pulse ECT developed post ECT confusion. She thereafter received Ultrabrief-pulse ECT without cognitive side effects, though in the absence of SNRI. Clearly, combination SNRI and Brief Pulse ECT causes confusion, hence if a patient is on an SNRI, Ultrabrief-pulse ECT is of choice.