Effects of acetaminophen and ibuprofen on renal function in anesthetized normal and sodium-depleted dogs

In certain conditions, renal prostaglandins (PGs) are importantdeterminants of kidney function. Under these "renal PG-dependent states," pharmacological inhibition of vasodilatory PG may result inexcessive renal vasoconstriction and adversely affect kidney function.The purposes of this study were to determine whether acetaminophen(Acet), a weak PG-synthesis inhibitor, influences kidney function inthe renal PG-dependent state of anesthesia and sodium depletion.Comparisons were made with ibuprofen (Ibu). Measurements ofPGE₂ excretion were used to assessrenal PG synthesis. Acet (15 mg/kg) and Ibu (10 mg/kg) both decreasedrenal blood flow and glomerular filtration rate by ~20-30% innormal, anesthetized, sodium-replete dogs. Although Acet producedsimilar changes in renal blood flow and glomerular filtration rate inthe low-sodium dogs, Ibu caused a significantly greater renalvasoconstriction (64 ± 10%) in these animals. Both Acet and Ibuinhibited urinary PGE₂ excretionin sodium-replete and low-sodium dogs. Ibu tended to have a greater andmore prolonged effect than did Acet. These results suggest that Acetalters PGE₂ excretion and kidneyfunction under renal PG-dependent conditions; the effects, however, are less severe than those seen with Ibu.