No abstract

Objectives: Liposome (LIP)-like lipid dispersions have emerged as useful detoxification vehicles in vitro. The authors compare resuscitation with tailored LIPs, 20% intravenous lipid emulsion (ILE), and sodium bicarbonate (BIC), in a rabbit model of clomipramine toxicity.Methods: Sedated, instrumented New Zealand white rabbits underwent clomipramine infusion at 3.2 mg/kg/min to 50% baseline mean arterial pressure (MAP) and then at 1.6 mg/kg/min for 30 minutes. BIC (3 mL/kg 8.4%), ILE (3 mL/kg 20%), or LIP (24 mg/kg) were infused as rescue treatments at toxicity and were repeated at 10 minutes (n = 5 in each group). remains a difficult therapeutic challenge. Mainstays of therapy include aggressive supportive care and sodium bicarbonate (BIC)-initiated systemic alkalinization. 1 More recently, intravenous lipid emulsion (ILE) preparations have been forwarded as adjuncts to standard management of TCA toxicity with successful reports of use in animal models 2 and human subjects. 3 Both pharmacokinetic and pharmacodynamic mechanisms have been forwarded to explain the beneficial effects of ILE. The widely held lipid sink theory is that lipid sequesters certain xenobiotics (such as TCAs) and reduces toxicity by decreasing the free serum concentration of the offending toxin. 4,5 Liposomes are spherical vesicles of phospholipids and effectively sequester amitriptyline and imipramine in vitro. 6,7 Specific advantages afforded by liposomes (LIPs) include increased surface area:volume ratios, the ability to modulate surface charge and internal pH, and the inherent lipid bilayer structure. To date, however, there are limited data on the antidotal efficacy of liposomal formulations in intact animal models.We examined the effect of LIPs in an established animal model of TCA toxicity. Specifically, in this study we compare resuscitation with bicarbonate (BIC), ILE, and LIPs in a previously studied rabbit model of clomipramineinduced shock. METHODS Study DesignThis was a laboratory study of clomipramine-induced cardiotoxicity in a rabbit model. The study was approved by the institutional ethics committee of the