Overview
DESCRIPTION The chemical name of cidofovir USP is 1-[( S )-3-hydroxy-2-(phosphonomethoxy)propyl]cytosine dihydrate (HPMPC), with the molecular formula of C 8 H 14 N 3 O 6 P• 2 H 2 O and a molecular weight of 315.22 (279.19 for anhydrous). The chemical structure is: Cidofovir USP is a white crystalline powder with an aqueous solubility of ≥ 170 mg/mL at pH 6 to 8 and a log P (octanol/aqueous...
Mechanism of Action
CLINICAL PHARMACOLOGY PHARMACOKINETICS Cidofovir injection must be administered with probenecid. The pharmacokinetics of cidofovir, administered both without and with probenecid, are described below. The pharmacokinetics of cidofovir without probenecid were evaluated in 27 HIV-infected patients with or without asymptomatic CMV infection. Dose-independent pharmacokinetics were demonstrated after one hr infusions of 1 (n = 5), 3 (n = 10), 5 (n = 2) and 10 (n = 8) mg/kg (See Table 2 for pharmacokinetic parameters). There was no evidence of cidofovir accumulation after 4 weeks of repeated administration of 3 mg/kg/week (n = 5) without probenecid.
Indications
- INDICATION AND USAGE Cidofovir injection is indicated for the treatment of CMV retinitis in patients with acquired immunodeficiency syndrome (AIDS). THE SAFETY AND EFFICACY OF CIDOFOVIR INJECTION HAVE NOT BEEN ESTABLISHED FOR TREATMENT OF OTHER CMV INFECTIONS (SUCH AS PNEUMONITIS OR GASTROENTERITIS), CONGENITAL OR NEONATAL CMV DISEASE, OR CMV DISEASE IN NON-HIV-INFECTED INDIVIDUALS. DESCRIPTION OF CLINICAL TRIALS Three phase II/III controlled trials of cidofovir injection have been conducted in HIV-infected patients with CMV retinitis.
Common Doses
- 1.5 mg
- 55 mL
- 100 mg
- 5 mg
Dosage
DOSAGE AND ADMINISTRATION CIDOFOVIR INJECTION, USP MUST NOT BE ADMINISTERED BY INTRAOCULAR INJECTION. Dosage THE RECOMMENDED DOSAGE, FREQUENCY, OR INFUSION RATE MUST NOT BE EXCEEDED. CIDOFOVIR INJECTION, USP 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 CIDOFOVIR INFUSION. Induction Treatment The recommended induction dose of cidofovir injection for patients with a serum creatinine of ≤1.
Black Box Warning
WARNING RENAL IMPAIRMENT IS THE MAJOR TOXICITY OF CIDOFOVIR INJECTION. CASES OF ACUTE RENAL FAILURE RESULTING IN DIALYSIS AND/OR CONTRIBUTING TO DEATH HAVE OCCURRED WITH AS FEW AS ONE OR TWO DOSES OF CIDOFOVIR INJECTION. TO REDUCE POSSIBLE NEPHROTOXICITY, INTRAVENOUS PREHYDRATION WITH NORMAL SALINE AND ADMINISTRATION OF PROBENECID MUST BE USED WITH EACH CIDOFOVIR INFUSION. RENAL FUNCTION (SERUM CREATININE AND URINE PROTEIN) MUST BE MONITORED WITHIN 48 HOURS PRIOR TO EACH DOSE OF CIDOFOVIR INJECTION AND THE DOSE OF CIDOFOVIR INJECTION MODIFIED FOR CHANGES IN RENAL FUNCTION AS APPROPRIATE (SEE...
Contraindications
- CONTRAINDICATIONS Initiation of therapy with cidofovir injection is contraindicated in patients with a serum creatinine >1.5 mg/dL, a calculated creatinine clearance ≤55 mL/min, or a urine protein ≥100 mg/dL (equivalent to ≥2+ proteinuria). Cidofovir injection is contraindicated in patients receiving agents with nephrotoxic potential. Such agents must be discontinued at least seven days prior to starting therapy with cidofovir injection. Cidofovir injection is contraindicated in patients with hypersensitivity to cidofovir.
Side Effects
- ADVERSE REACTIONS Nephrotoxicity: Renal toxicity, as manifested by ≥2+ proteinuria, serum creatinine elevations of ≥0.4 mg/dL, or decreased creatinine clearance ≤55 mL/min, occurred in 79 of 135 (59%) patients receiving cidofovir injection at a maintenance dose of 5 mg/kg every other week. Maintenance dose reductions from 5 mg/kg to 3 mg/kg due to proteinuria or serum creatinine elevations were made in 12 of 41 (29%) patients who had not received prior therapy for CMV retinitis (Study 106) and in 19 of 74 (26%) patients who had received prior therapy for CMV retinitis (Study 107).
Interactions
- Drug Interactions Probenecid Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine). Concomitant medications should be carefully assessed. Zidovudine should either be temporarily discontinued or decreased by 50% when coadministered with probenecid on the day of cidofovir infusion.