Since COX-1 and COX-2 are involved in OAT function and 3b and 4 have affinity for these enzymes,23,24 the decrease in PAH secretion is possibly related to this mechanism as well as to the competition for OATs transport,61 which can be proved by the reduction of PAH t/m ratio produced by APAP. Here, OAT is linked to pulmonary arterial hypertension.