Astra USA, Inc.

To evaluate the safety and efficacy of foscarnet induction treatment of cytomegalovirus (CMV) retinitis in AIDS patients who have previously suffered severe dose-limiting ganciclovir-related myelosuppression, who are ineligible for ganciclovir treatment due to myelosuppression or who have clearly failed to have a therapeutic response to ganciclovir therapy. To assess the duration of clinical response. To evaluate the effect on quantitative CMV cultures of blood and urine. To determine the effect on recovery of HIV p24 antigen capture direct from plasma.

To assess the relative efficacy of oral versus intravenous hydration during foscarnet sodium (Foscavir) induction therapy, as determined by changes in creatinine clearance. To estimate the timing and volume of oral fluid hydration required to establish a diuresis before and during intravenous Foscavir therapy. To assess the general tolerance of two hydration regimens by the adverse event profile associated with each.

To determine whether acute ionized hypomagnesemia and hypocalcemia immediately following foscarnet infusions can be lessened or eliminated by prior infusion of magnesium sulfate. To determine whether reductions in ionized magnesium, ionized calcium, and parathyroid hormone levels following foscarnet infusions are lessened by preinfusion of magnesium sulfate. To evaluate the safety of intravenous magnesium sulfate prior to foscarnet infusion by monitoring blood pressure, heart rate, and heart rhythm. To characterize the effect of magnesium sulfate on foscarnet blood levels and urinary excretion of calcium, magnesium, phosphate, and foscarnet.