Rescue of amitriptyline-intoxicated hearts with nanosized vesicles

Amitriptyline, one of the most prescribed antidepressants, is reported to claim a large number of human lives due to drug overdose related cardiac arrest. Although amitriptyline poisoning has long been recognized as a frequent and serious fatality in the medical field, few efforts have been made to devise methods for treating its toxicity. To address this issue, phospholipid-based nanosized vesicles (spherulites) were employed to reverse the cardiotoxicity induced by amitriptyline in an isolated heart perfusion model.

The ability of spherulites to efficiently take up amitriptyline was first established in vitro in protein free and albumin-containing buffers. Vesicles bearing an internal pH of 3.0 or 7.4 were then infused into amitriptyline pre-intoxicated isolated rat hearts, and changes in coronary perfusion pressure (CPP), the first derivative of left ventricular pressure (dP/dt max) and heart rate were monitored. Control hearts received no vesicles.

Based on the recoveries in CPP observed, the efficacies of the formulations were ranked as follows: control=pH 7.4-spherulites

These data suggest that spherulites have a protective effect against acute cardiovascular failure following intoxication with amitriptyline and possibly other cardiotoxic drugs. It appears that the beneficial effects derived from the formulation infusion involved restoration of both haemodynamic and metabolic oxygen demands on the heart.