Foscarnet Sodium

Foscarnet must be given by the intravenous route only, either via a central venous line or directly into peripheral veins. If peripheral veins are considered, Foscarnet 24 mg/mL must be diluted with glucose (dextrose) 5% or normal saline to a concentration of 12 mg/mL immediately prior to administration. Foscarnet 24mg/ml in 250 ml solution may be given without dilution via a central vein.

Induction Therapy for CMV Retinitis: Foscarnet can be given over 2-3 weeks, depending on clinical response, as intermittent infusions every 8 hours at a dose of 60 mg/kg in patients with normal renal function. The time of infusion should not be shorter than one hour for the 60 mg/kg dose.

Maintenance Therapy for CMV Retinitis: Following maintenance therapy, foscarnet is given 7 days a week as a once-daily infusion over 2 hours at a dose specified by renal function as evaluated by creatinine clearance. The dose range is 90-120 mg/kg/day for those with normal renal function. It is required to start treatment at 90 mg/kg and increase up to 120 mg/kg in those in whom retinitis is progressing and who tolerate the lower dose.

Induction Therapy for HSV Infections: Foscarnet is given at a dose of 40 mg/kg, over 60 minutes, every 8 hours, in those with normal renal function. The time of infusion should not be shorter than 60 minutes. The time span taken for healing typically depends on the size of the initial lesion and foscarnet treatment should continue until complete re-epithelialization occurs, usually 2 to 3 weeks.

Maintenance Therapy for HSV Infections: The efficacy of Foscarnet 24mg/mL (250 mL) maintenance therapy in the treatment of aciclovir-resistant herpes simplex virus (HSV) infections has not been established.

The most commonly reported side effects of Foscarnet Sodium injection include: fever, flu-like symptoms, chest pain, headache, back pain, vomiting, nausea, and diarrhea.

• Contact with eyes and skin may be responsible for causing a burning sensation and local irritation. In case of accidental contacts, the exposed area must be rinsed promptly with the help of cold water.
• Foscarnet injection is not recommended for use in all those patients who are undergoing haemodialysis as dosage guidelines have not been established.
• Use foscarnet with caution in those with reduced renal function. Since renal function impairment may occur during foscarnet uses, monitor serum creatinine every second day during induction therapy and once in a week during maintenance therapy.
• To scale down the potential of renal function impairment, adequate hydration needs to be maintained in all patients. Renal function of those with renal disease or taking concomitant therapy with other nephrotoxic medicines must be closely assessed.
• Due to the existence of sodium content in Foscarnet medicine, avoid its use when a saline load is difficult to be tolerated (in cardiomyopathy). This should also be taken into consideration by all the respective patients who are on a controlled sodium diet.
• Specific caution is required in those with reduced calcium levels prior to treatment and in those with other drugs known to influence the serum calcium levels. Electrolytes, mainly magnesium and calcium, should be evaluated before and during foscarnet injection 24mg/mL in 250 mL therapy and deficiencies corrected.
• Patients with any known existing prolongation of cardiac conduction intervals, mainly QTc, in those with electrolyte disturbances (hypomagnesaemia, hypokalaemia, hyperkalaemia,), or bradycardia, as well as those with underlying cardiac diseases should be precisely monitored due to increased probability of ventricular arrhythmia.
• Seizures, associated with alterations in plasma minerals and electrolytes, have been linked with foscarnet therapy. Status epilepticus may occur. Therefore, carefully monitor patients for such changes and their potential sequelae. Mineral and electrolyte supplementation can be used.
• Foscarnet may be excreted in high concentrations in the urine and may be responsible for genital irritation and ulceration. To prevent irritation and/or ulceration, precise attention to personal hygiene is required and cleaning of the genital area after each micturition is required.
• Since there is no clinical experience or investigational findings available, Scarnet 24mg/mL in 250 mL should not be prescribed to pregnant women and during lactation.
• Women capable of childbearing must use apt and effective contraception methods during Scarnet therapy. Men treated with this medicine should not father a child throughout or up to 6 months after therapy.

Foscarnet contains no preservative and if the sterility seal of a bottle has been broken the Foscarnet solution should be discarded within 24 hours.

Store below 25°C. Do not refrigerate. In case refrigerated precipitation may occur. By keeping the Foscarnet bottle at room temperature with repeated shaking, the precipitate can be turned back into solution again.

• Since foscarnet 24mg/mL in 250 mL injection can impair renal function, additive toxicity may appear when used along with other nephrotoxic medications such as amphotericin B, ciclosporin A, aminoglycosides, methotrexate, aciclovir and tacrolimus.
• Since foscarnet injection can reduce serum levels of ionized calcium, additional caution is required when used along with other medicines known to affect serum calcium levels, like IV pentamidine.
• Renal impairment and symptomatic hypocalcemia (Trousseau’s and Chvostek’s signs) may occur during concurrent treatment with IV pentamidine and foscarnet. Abnormal renal function may occur in connection with the use of foscarnet along with ritonavir or saquinavir.