Plasma lithium concentrations should be monitored carefully during concomitant captopril therapy. Clinicians should note that some other antihypertensive agents may also interact with lithium. Serious adverse hematological effects, including neutropenia and agranulocytosis, have been reported infrequently during captopril therapy. Patients with impaired renal function, patients with collagen vascular disease, or patients receiving large daily doses are at greater risk. Captopril can affect renal function.
Renal insufficiency can occur but is usually reversible following discontinuance of captopril.
Polyuria and oliguria have also been reported, though rarely, during captopril therapy. These effects on renal function may resolve if hypovolemia and hyponatremia are corrected. If renal artery stenosis is suspected, captopril therapy should be discontinued. Although rare, serious renal effects include acute renal tubular necrosis, nephrotic syndrome, glomerulonephritis, and interstitial nephritis. This effect is believed to result from the pharmacologic activity of the drug's sulfhydryl group.