Intralipid infusion ameliorates propranolol-induced hypotension in rabbits

Abstract

Recent case reports of successful amelioration of lipid-soluble drug toxidromes with Intralipid infusion have prompted interest in the scope of lipid emulsions as antidotal therapy. Propranolol is a highly lipid-soluble, nonselective beta-blocker with additional local-anaesthetic properties. We explored the hypothesis that propranolol toxicity may be similarly attenuated by Intralipid infusion in a rabbit model. Twenty sedated, invasively monitored, and mechanically ventilated New Zealand White rabbits underwent propranolol infusion at 4.2 mg/min to a target mean arterial pressure (MAP) of 60% baseline MAP. Animals subsequently received 6 ml/kg 20% Intralipid, or 6 ml/kg 0.9% saline solution over a 4-minute period. Pulse rate and MAP were recorded at 2.5-minute intervals to 15 minutes. MAP was greatest in the Intralipid group (median 69 mmHg, interquartile range [IQR] 17.5 mmHg Intralipid vs. median 53 mmHg, IQR 12.75 mmHg saline; p=0.029) at 15 minutes. No difference was observed in first derivative of MAP, or pulse rate between groups. Propranolol-induced hypotension is ameliorated by Intralipid infusion in this intact rabbit model. The mechanism of action remains to be elucidated.