Renal function after acyclovir intravenous injection.

Plasma urea or creatinine was noted to be raised in 58 of 354 patients treated with intravenous acyclovir. This occurred after intravenous bolus injection of high dosages of acyclovir but the risk was considerably reduced by slow intravenous infusion of the same dosage over one hour, with adequate hydration of the patient and adjustment of dosage in patients with preexisting impaired renal function. Animal studies indicate that the impairment of renal function associated with high bolus injections of acyclovir is due to crystal formation in the renal tubules and/or the collecting ducts, and that the crystals are removed after cessation of treatment. The special problems involved in the treatment of patients with herpes encephalitis necessitating limited fluid intake and the possible interaction with other nephrotoxic drugs are discussed.