Drug Characteristics
  • Formulation

    Infusion: 24 mg/ml (250 ml, 500 ml)

    foscarnet cream (2%) Unlicensed in UK, available from special order manufacturers

  • Dose

    CMV retinitis infection:

    Induction treatment: 90 mg/kg IV 12 hourly for 14–21 days.

    Maintenance treatment:

    Initiate at 60 mg/kg IV once a day and if tolerated increase to 90–120 mg/kg IV once a day.

    Exact doses depend on renal function

    Direct intraocular injection:

    Usual injection prepared as 2400 mg/0.1ml (0.05ml injected). Injection frequency varied according to response

    CMV colitis, oesophagitis:

    Second line after ganciclovir

    foscarnet IV 90 mg/kg twice a day for 14–28 days

    Resistant herpes simplex infection:

    40 mg/kg IV 8–12 hourly for 2–3 weeks until healing

    Progressive outer retinal necrosis (PORN):

    aciclovir 10 mg/kg IV three times a day with foscarnet 90 mg/kg IV twice a day

  • Side Effects

    Renal toxicity; electrolyte disturbances (hypokalaemia, hypocalcaemia, (especially if used in conjunction with IV pentamidine) hypomagnesaemia);

    genital ulceration; abnormal LFTs; thrombophlebitis; anaemia; gastrointestinal disturbances; peripheral tingling; seizures; tremor; confusion

    Addition hydration oral or IV

    Irritation or genital ulceration can be prevented by ensuring careful washing of the genital area after micturation

  • Interactions

    Additive toxicity with other nephrotoxic drugs e.g. aminoglycosides, amphotericin, IV pentamidine. Use with extreme caution

    Cidofovir contraindicated

  • Renal

    GFR (ml/min)

    See SmPC for dosage reduction according to creatinine clearance

    Monitor renal function every second day during induction and weekly during maintenance

  • Hepatic

    No dosage reduction required.

    Monitor LFTS

  • Pregnancy

    Compatible – Maternal Benefit >> Embryo-Foetal Risk

  • Other Information