Adult Dosing
CMV retinitis in AIDS patients
- Induction treatment
- 90 mg/kg IV over 1.5-2 hrs q12 hrs x 2-3 hrs for 2 to 3 weeks
- Alt: 60 mg/kg IV over 1 hr q8 hrs x 2-3 hrs for 2 to 3 weeks
- Maintenance Treatment
- 90 mg/kg/day IV over 2 hrs, May increase to 120 mg/kg/day IV over 2 hrs every 24 hours
- Max: 120 mg/kg/day
Acyclovir resistant mucocutaneous HSV infections
- Induction treatment: 40mg/kg IV over 1 hr q8-12 hrs x 2-3 wks or until healed
Note:
- Use infusion pump to control the rate of infusion
- To minimize renal toxicity, adequately hydrate the patient to establish diuresis both prior to and during treatment
Pediatric Dosing
- Safety and effectiveness in pediatric patients have not been established
[Outline]
Renal Dose Adjustment (Based on CrCl)
CMV retinitis
- Induction treatment
- >1.4 mL/min/kg: 60 mg/kg q8 hrs or 90 mg/kg q12 hrs
- >1.0-1.4 mL/min/kg: 45 mg/kg q8 hrs or 70 mg/kg q12 hrs
- >0.8-1.0 mL/min/kg: 50 mg/kg q12 hrs
- >0.6-0.8 mL/min/kg: 40 mg/kg q12 hrs or 80 mg/kg q24 hrs
- >0.5-0.6 mL/min/kg: 60 mg/kg q24 hrs
0.4-0.5 mL/min/kg: 50 mg/kg q24 hrs- <0.4 mL/min/kg: Not recommended
- Maintenance Treatment
- >1.4 mL/min/kg: 90 mg/kg q24 hrs or 120 mg/kg q24 hrs
- >1.0-1.4 mL/min/kg: 70 mg/kg q24 hrs or 90 mg/kg q24 hrs
- >0.8-1.0 mL/min/kg: 50 mg/kg q24 hrs or 65 mg/kg q24 hrs
- >0.6-0.8 mL/min/kg: 80 mg/kg q48 hrs or 105 mg/kg q48 hrs
- >0.5-0.6 mL/min/kg: 60 mg/kg q48 hrs or 80 mg/kg q48 hrs
- 0.4-0.5 mL/min/kg: 50 mg/kg q48 hrs or 65 mg/kg q48 hrs
- <0.4 mL/min/kg: Not recommended
HSV infections
- >1.4 mL/min/kg:40 mg/kg q12 hrs or 40 mg/kg q8 hrs
- >1.0-1.4 mL/min/kg: 30 mg/kg q12 hrs or 30 mg/kg q8 hrs
- >0.8-1.0 mL/min/kg: 20 mg/kg q12 hrs or 35 mg/kg q12 hrs
- >0.6-0.8 mL/min/kg: 35 mg/kg q24 hrs or 25 mg/kg q12 hrs
- >0.5-0.6 mL/min/kg: 25 mg/kg q24 hrs or 40 mg/kg q24 hrs
- 0.4-0.5 mL/min/kg: 20 mg/kg q24 hrs or 35 mg/kg q24 hrs
- <0.4 mL/min/kg: Not recommended
Hepatic Dose Adjustment
- Hepatic impairment: Dose adjustments not defined
- Renal impairment is the major toxicity of foscarnet. Adjust the dose based on serum creatinine levels [US Black Box Warning]
- Change in serum electrolytes including hypocalcemia, hypophosphatemia, hyperphosphatemia, hypomagnesemia, and hypokalemia has been reported with foscarnet therapy
- Closely monitor and treat electrolyte imbalance before treatment and especially in those with neurologic or cardiac abnormalities and those receiving other drugs known to influence minerals and electrolytes. To decrease or prevent these symptoms use infusion pump for the administration of foscarnet
- Seizures related to alteration in plasma minerals and electrolytes have been reported with foscarnet therapy. Impaired baseline renal function, low total serum calcium, and underlying CNS conditions are the risk factors [US Black Box Warning]
- To avoid local irritation foscarnet should be administered only into veins with adequate blood flow to permit rapid dilution and distribution
- Male and female genital irritation/ulceration has been reported with foscarnet therapy due to the presence of drug in the urine. Advise patient to follow personal hygiene and adequate hydration to minimize the occurrence
- Anemia, granulocytopenia and neutopenia has been reported with foscarnet therapy
Cautions: Use cautiously in
- Renal impairment
- Electrolyte imbalance
- Myelosuppression
- Seizure disorder
- Concomitant nephrotoxic agent
- Cardiac diseases
- Neurologic diseases
Pregnancy Category:C
Breastfeeding: Safety unknown, excreted in rat milk at concentrations three times higher than peak maternal blood concentrations, it is not known whether excreted in human milk. Manufacturer advises caution.
