Proper Use

Drug information provided by: Micromedex

To ensure the best response, foscarnet must be given for the full time of treatment. Also, this medicine works best when there is a constant amount in the blood. To help keep the amount constant, foscarnet must be given on a regular schedule.

Several glasses of water should be taken every day, unless otherwise directed by your doctor. Drinking extra water will help to prevent some unwanted effects foscarnet has on the kidneys.

This medicine may cause sores on the genitals (sex organs). Washing your genitals after urination may decrease the chance of your developing this problem.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For injection dosage form:
    • For cytomegalovirus (CMV) retinitis induction (first stage of dosing):
      • Adults and children—The usual dose is 60 milligrams (mg) per kilogram (kg) (27.3 mg per pound) of body weight every eight hours for fourteen to twenty-one days. Each dose is injected slowly into a vein by an infusion pump over at least one hour.
    • For CMV retinitis maintenance (second stage of dosing):
      • Adults and children—The usual dose is 90 to 120 mg per kg (41 to 54.5 mg per pound) of body weight once a day. This dose is injected slowly into a vein by an infusion pump over at least two hours.
    • For herpes simplex infections:
      • Adults and children—The usual dose is 40 mg per kg (18.2 mg per pound) of body weight given either every eight or every twelve hours. This dose is injected slowly into a vein by an infusion pump over at least one hour. Treatment is usually continued for two to three weeks or until the infection in healed.