Complications of therapy with intravenous cidofovir: Severe nephrotoxicity and anterior uveitis

Intravenous cidofovir is a new drug approved for the treatment of cytomegalovirus retinitis. Mild to moderate renal impairment was reported in 12%-17% of patients in two recent clinical trials. Uveitis was not reported as a complication in these trials. The first 20 patients treated with cidofovir at a large urban county hospital HIV clinic were reviewed. Three patients developed severe nephrotoxicity, two of whom died. In addition, five cases of anterior uveitis (two of whom also had renal failure), which occurred after receiving a mean of 5.4 (range, 2-13) cidofovir doses, were noted. One patient developed a cataract related to prior cidofovir-induced uveitis. Risk factors for nephrotoxicity seemed to include a prior episode of renal impairment, concomitant or prior nephrotoxic agents, and inconsistent dosing, which was due to patients not taking all of the prescribed doses of probenecid. Risk factors for uveitis seemed to include prior or concurrent renal impairment (three of five patients) and concomitant use of protease inhibitors (five of five patients). Uveitis improved with topical corticosteroids; however, recurrence of symptoms was noted in the two patients in whom cidofovir was continued. Intravenous cidofovir should be administered cautiously, after careful patient screening, to avoid potentially serious toxicities.