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Vasopressor therapy in atypical antipsychotic overdose

V Pillay-Fuentes Lorente, R van Rensburg, D A Cloete, S Lahri, E H Decloedt

Abstract


Hypotension is a common presentation following an overdose of quetiapine. Adrenaline is often used as the vasopressor of choice for hypotension not responding to intravenous fluids. We present a case of quetiapine overdose with hypotension unresponsive to high-dose adrenaline. The patient was commenced on noradrenaline and made a full recovery. We highlight learning points about vasopressor therapy for atypical antipsychotic overdose. Quetiapine-induced hypotension is thought to be mediated by α1-receptor antagonism. Adrenaline is unlikely to improve blood pressure, as it is an agonist at both α- and β-receptors. Alpha-2- and β2-agonism can reduce sympathetic outflow and cause vasodilation, respectively, further exacerbating the hypotension. Noradrenaline is the preferred vasopressor of choice for hypotension caused by quetiapine overdose, as it has less affinity for α2- and β2-receptors, but maintains α1-receptor agonism. Drugs with a similar mechanism of inducing hypotension should also be treated with noradrenaline as the vasopressor of choice.


Authors' affiliations

V Pillay-Fuentes Lorente, Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa

R van Rensburg, Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa

D A Cloete, Division of Emergency Medicine, Department of Family Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa

S Lahri, Division of Emergency Medicine, Department of Family Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa

E H Decloedt, Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa

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Keywords

Quetiapine, Noradrenaline, Adrenaline, Hypotension

Cite this article

South African Medical Journal 2020;110(10):1003-1005. DOI:10.7196/SAMJ.2020.v110i10.14771

Article History

Date submitted: 2020-09-30
Date published: 2020-09-30

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