Abstract

Acetaminophen (paracetamol) continues to be one of the leading, international over-the-counter analgesics. Unlike the COX-2 inhibitors, no adverse cardiovascular effects have been associated with acetaminophen usage in safe, therapeutic dosages. There are few rigorous physiological investigations of its actions/mechanisms of action. Several investigations, in recent years, have questioned its potential activity in the mammalian cardiovascular system. Our laboratory has found some positive salutary effects in myocardial ischemia/reperfusion injury and during myocardial infarction. In addition, another laboratory found concomitant cardioprotective effects during the acute phase of myocardial infarction. They report similar effects of the ability of acetaminophen to reduce the severity of myocardial infarction and ultimately result in improved mortality rates. They also postulate that this attenuation in myocardial damage is mediated through antioxidant means. Others have not found similar results but have reported no detrimental cardiovascular actions of acetaminophen in experimental animals. The inconsistency in results probably reflects multiple differences in experimental approaches, including use of different species, different experimental preparations, different drug concentrations, and different routes/modes of administering/preparing the drug. The current review focuses on this recent research and tries to provide new perspectives for future investigations. In particular, we have identified new cellular/subcellular targets at which acetaminophen might be acting. These include matrix metalloproteinases and the mitochondrial permeability transition pore. Future work will help identify additional tissue/organ actions of acetaminophen and its as-yet-unknown mechanisms of action.

Keywords: Cardioprotection, myocardial infarction, analgesics, mitochondria