Vasopressor therapy in atypical antipsychotic overdose

Area of Science:

• Pharmacology
• Toxicology
• Emergency Medicine

Background:

• Hypotension is a frequent complication of quetiapine overdose.
• Adrenaline is typically the first-choice vasopressor for managing hypotension unresponsive to fluid resuscitation.

Observation:

• A case of quetiapine overdose presented with severe hypotension refractory to high-dose adrenaline therapy.
• The patient's condition improved significantly after initiating noradrenaline infusion.

Findings:

• Quetiapine-induced hypotension is primarily mediated by alpha-1 (α1) adrenergic receptor antagonism.
• Adrenaline's combined alpha (α) and beta (β) receptor agonism, including α2 and β2 agonism, can worsen hypotension by reducing sympathetic outflow and causing vasodilation.
• Noradrenaline, with its potent α1 agonism and weaker β-receptor activity, is more effective in counteracting quetiapine-induced hypotension.

Implications:

• Noradrenaline should be considered the vasopressor of choice for managing hypotension resulting from quetiapine overdose.
• This finding extends to other drugs with similar mechanisms of hypotension, suggesting noradrenaline as a preferred treatment strategy.
• Clinical guidelines for managing atypical antipsychotic overdoses may need updating regarding optimal vasopressor selection.