Intralipid infusion ameliorates propranolol-induced hypotension in rabbits.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Propranolol-induced hypotension is ameliorated by Intralipid infusion in this intact rabbit model. The mechanism of action remains to be elucidated.
Harvey
Martyn G
MG
Department of Emergency Medicine, Waikato Hospital, Hamilton, New Zealand. harveym@waikatodhb.govt.nz
Cave
Grant R
GR
D000319:Adrenergic beta-Antagonists; D000818:Animals; D000931:Antidotes / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects; D004195:Disease Models, Animal; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D007261:Infusions, Intra-Arterial; D008297:Male; D011433:Propranolol; D011817:Rabbits; D013997:Time Factors
D000319:Adrenergic beta-Antagonists; D000931:Antidotes; D005217:Fat Emulsions, Intravenous; D011433:Propranolol