Several agents that cross the placenta (see Chapter 15) can damage the fetal kidney, including aminoglycosides, ACE inhibitors, heavy metals, and organic solvents (Table 42-10) (579). Chapters 15 and 56 provide a discussion of the relevant pharmacokinetics. Nephrotoxicity may result from renal ischemia or direct cytotoxicity, or both. Direct cytotoxicity is related to the concentration of drug or metabolite in renal tubular cells, which depends on the concentration of free drug in the plasma, GFR, and tubular transport.

Nephrotoxicity may present as oligoanuria, ARF, drug toxicity caused by decreased clearance of a medication with renal excretion, hypotension, hematuria, proteinuria, RTA, nephrocalcinosis or nephrolithiasis, polyuria, abnormal plasma electrolyte concentrations, or cardiac arrhythmia (see Table 42-10). Because most NICU patients are exposed to multiple drugs as well to episodes of hypoxemia and ischemia, it often is very difficult to determine whether a particular drug is the major renal offender.