Renal effects of nonsteroidal anti-inflammatory drugs.

All nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase, and consequently renal functions dependent upon prostaglandin synthesis can be affected. Fortunately, renal function in normal individuals is relatively independent of the PG system, and thus the NSAIDs don't usually produce any renal dysfunction. However, in some circumstances, inhibition of PG dependent renal functions can produce clinically significant effects. When the kidney is in a salt retaining state or when there is renal vascular damage, NSAIDs can reduce renal blood flow and glomerular filtration rate producing acute renal failure that is reversible upon discontinuation of the drug. NSAIDs can also: 1) reduce sodium excretion and blunt the diuretic effect of loop diuretics, thus producing or exacerbating edema, 2) inhibit PG dependent renin secretion occasionally resulting in hyperkalemia, 3) enhance the antidiuretic effects of vasopressin and 4) reduce the antihypertensive efficacy of several drugs. Evidence that any NSAID "spares" renal cyclooxygenase is controversial, and no NSAID is devoid of clinical problems. Syndromes that are less obviously related to inhibition of renal PG synthesis are acute interstitial nephritis with or without the nephrotic syndrome, renal papillary necrosis, and chronic interstitial nephritis. Recently a unique syndrome of flank pain and mild reversible renal dysfunction has been described in healthy individuals receiving suprofen, a uricosuric NSAID. This syndrome may be due to uric acid crystal deposition in the renal tubules and has resulted in the removal of suprofen from the US market.