Nifedipine-induced renal dysfunction. Alterations in renal hemodynamics.

Nifedipine caused acute, reversible deterioration in renal function in four patients with chronic renal insufficiency. The absence of hypotension, clinical course, benign urinary sediments, and normal results of renal ultrasound examinations excluded acute tubular necrosis, pyelonephritis, interstitial nephritis, obstructive uropathy, and acute glomerulonephritis. It is postulated that this slow calcium channel blocker produced deleterious intrarenal hemodynamic alterations in the setting of moderate to severe renal functional impairment. Nifedipine may alter renal function by blocking calcium entry into renal vascular smooth muscle, thereby reducing the efficacy of vasoconstrictor hormones in regulation of renal blood flow and glomerular filtration rate. An alternative explanation is that nifedipine may inhibit the compensatory synthesis of vasodilatory prostaglandin E2 analogous to the clinical observation of acute deterioration in renal function by nonsteroidal anti-inflammatory drugs in patients with pre-existing renal insufficiency. These observations suggest that clinicians should monitor renal function closely and exercise caution when administering nifedipine to patients with underlying renal insufficiency.