Use of enoximone in management of anaphylaxis complicated by labetalol use.

A 42-year-old woman with end-stage renal failure was admitted to the intensive care unit following resuscitation from a pulseless electrical activity cardiac arrest after intravenous piperacillin/tazobactam. Persistent bradycardia and hypotension, unresponsive to epinephrine and norepinephrine, were suspected to have been exacerbated by chronic labetalol therapy for resistant arterial hypertension. As an alternative, the non-adrenergic inotrope, enoximone, was started. This, combined with thrombolysis for possible pulmonary embolism, heralded significant haemodynamic improvement, allowing weaning from inotropic support. A clear CT pulmonary angiogram 2 days post-arrest and significantly raised mast cell tryptase levels confirmed anaphylaxis rather than pulmonary embolism as the precipitating cause. We believe this to be the first case report of phosphodiesterase-III inhibitor use in the management of anaphylaxis complicated by α/β-blockade, and discuss the mechanism behind this effect and comparison with the more commonly reported use of glucagon.