| Treatment of cytomegalovirus (CMV) retinitis: (Patient must meet the following criteria first: serum creatinine ≤ 1.5, CRCL >55ml/min and urine protein < 100 mg/dL).
Induction: 5 mg/kg qweek x 2.
Maintenance: 5 mg/kg q2weeks.
Note: Probenecid must be administered orally with each dose of cidofovir.
DOSAGE AND ADMINISTRATION
VISTIDE MUST NOT BE ADMINISTERED BY INTRAOCULAR INJECTION.
THE RECOMMENDED DOSAGE, FREQUENCY, OR INFUSION RATE MUST NOT BE EXCEEDED. VISTIDE MUST BE DILUTED IN 100 MILLILITERS 0.9% (NORMAL) SALINE PRIOR TO ADMINISTRATION. TO MINIMIZE POTENTIAL NEPHROTOXICITY, PROBENECID AND INTRAVENOUS SALINE PREHYDRATION MUST BE ADMINISTERED WITH EACH VISTIDE INFUSION.
The recommended induction dose of VISTIDE for patients with a serum creatinine of ≤ 1.5 mg/dL, a calculated creatinine clearance > 55 mL/min, and a urine protein < 100 mg/dL (equivalent to < 2+ proteinuria) is 5 mg/kg body weight (given as an intravenous infusion at a constant rate over 1 hr) administered once weekly for two consecutive weeks. Because serum creatinine in patients with advanced AIDS and CMV retinitis may not provide a complete picture of the patient's underlying renal status, it is important to utilize the Cockcroft-Gault formula to more precisely estimate creatinine clearance (CrCl). As creatinine clearance is dependent on serum creatinine and patient weight, it is necessary to calculate clearance prior to initiation of VISTIDE.
CrCl (mL/min) should be calculated according to the following formula:
|Creatinine clearance for males =
|| [140-age (years)]× [body wt (kg)]
72 × [serum creatinine (mg/dL)]
|Creatinine clearance for females =
|| [140-age (years)]× [body wt (kg)]× 0.85
72 × [serum creatinine (mg/dL)]
The recommended maintenance dose of VISTIDE is 5 mg/kg body weight (given as an intravenous infusion at a constant rate over 1 hr), administered once every 2 weeks.
Changes in Renal Function During VISTIDE Therapy
The maintenance dose of VISTIDE must be reduced from 5 mg/kg to 3 mg/kg for an increase in serum creatinine of 0.3 – 0.4 mg/dL above baseline. VISTIDE therapy must be discontinued for an increase in serum creatinine of ≥ 0.5 mg/dL above baseline or development of ≥ 3+ proteinuria.
Preexisting Renal Impairment
VISTIDE is contraindicated in patients with a serum creatinine concentration > 1.5 mg/dL, a calculated creatinine clearance ≤ 55 mL/min, or a urine protein ≥ 100 mg/dL (equivalent to ≥ 2+ proteinuria).
Probenecid must be administered orally with each VISTIDE dose. Two grams must be administered 3 hr prior to the VISTIDE dose and one gram administered at 2 and again at 8 hr after completion of the 1 hr VISTIDE infusion (for a total of 4 grams).
Ingestion of food prior to each dose of probenecid may reduce drug-related nausea and vomiting. Administration of an antiemetic may reduce the potential for nausea associated with probenecid ingestion. In patients who develop allergic or hypersensitivity symptoms to probenecid, the use of an appropriate prophylactic or therapeutic antihistamine and/or acetaminophen should be considered (see CONTRAINDICATIONS).
Patients must receive at least one liter of 0.9% (normal) saline solution intravenously with each infusion of VISTIDE. The saline solution should be infused over a 1–2 hr period immediately before the VISTIDE infusion. Patients who can tolerate the additional fluid load should receive a second liter. If administered, the second liter of saline should be initiated either at the start of the VISTIDE infusion or immediately afterwards, and infused over a 1 to 3 hr period.