Pregnancy and renal failure - The case for application of dosage guidelines

Pregnancies in women with renal disease, undergoing dialysis treatment or w ith kidney transplants are increasingly observed. Serious problems with dru g dose adjustment may arise in pregnant women with renal impairment. This r eview gives a practical overview on the risks of drug use during gestation, the recommended drugs of choice (e.g. methyldopa, cyclosporin), and provid es some proposals for dosage adjustments in pregnant women with renal impai rment. In normal pregnancy, the glomerular filtration rate and plasma volume incre ase, whereas plasma protein binding and liver function may be impaired. An increase in dosage is needed for cyclosporin and for methadone because of i ncreased hepatic clearance. The dosage of erythropoetin must be increased b ecause of lower potency in pregnant women. Little more is known on the impa ct of gestation on drug dose, since pharmacokinetic studies are rarely done in pregnant women. The dosages of magnesium, lithium and morphine must be reduced in renal imp airment. Dose adjustment to renal function is critical and is essential for anti-infective agents (e.g. ceftazidime, ganciclovir). Basing drug dose on estimated creatinine clearance might be the most practical solution in pre gnant women with renal impairment.