Prothrombin time prolongation in paracetamol poisoning: a relevant marker of hepatic failure?

The association between paracetamol overdose and prolonged prothrombin time due to hepatic failure is well recognized. However, little is known of the possibility that paracetamol overdose can prolong the prothrombin time without overt hepatic failure. The few data from the literature suggest this is either due to a reduction in the functional levels of the vitamin K-dependent clotting factors by elevated doses of paracetamol, or a consequence of the administration of the antidote N-acetylcystein. The three reported cases provide further evidence that paracetamol overdose can be associated with a prolongation in the prothrombin time without overt hepatic failure. Even though the prothrombin time provides useful prognosis information, decisions regarding the management of these patients should not solely be based on this endpoint to avoid misinterpretation of the accuracy and the severity of liver failure.