About your treatment
Your doctor has ordered foscarnet, an antiviral agent, to help treat your infection. The drug will be added to an intravenous fluid that will drip through a needle or catheter placed in your vein for 1 to 2 hours, one to three times a day.
Foscarnet is used to treat cytomegalovirus (CMV) infections in patients whose immune system is not working properly (e.g., patients with acquired immunodeficiency syndrome [AIDS] or organ transplants). These infections include CMV retinitis (an eye infection). This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
Your health care provider (doctor, nurse, or pharmacist) may measure the effectiveness and side effects of your treatment using laboratory tests and physical examinations. It is important to keep all appointments with your doctor and the laboratory. The length of treatment depends on how your infection and symptoms respond to the medication.
Before administering foscarnet,
- tell your doctor and pharmacist if you are allergic to foscarnet or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially other antibiotics, probenecid (Benemid), ritonavir (Norvir), saquinavir (Fortovase, Invirase), zidovudine (AZT, Retrovir), and vitamins.
- tell your doctor if you have or have ever had kidney disease or anemia.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking foscarnet, call your doctor.
Administering your medication
Before you administer foscarnet, look at the solution closely. It should be clear and free of floating material. Gently squeeze the bag or observe the solution container to make sure there are no leaks. Do not use the solution if it is discolored, if it contains particles, or if the bag or container leaks. Use a new solution, but show the damaged one to your health care provider.
It is important that you use your medication exactly as directed. Do not stop your therapy on your own for any reason because your infection could worsen and result in hospitalization. Do not change your dosing schedule without talking to your health care provider. Your health care provider may tell you to stop your infusion if you have a mechanical problem (such as a blockage in the tubing, needle, or catheter); if you have to stop an infusion, call your health care provider immediately so your therapy can continue.
Foscarnet may cause side effects. The most serious side effect of foscarnet therapy is reduced kidney function. You can prevent this problem by following your doctor's directions concerning drinking plenty of fluids and/or infusing intravenous fluids along with your foscarnet.
Tell your health care provider if any of these symptoms are severe or do not go away:
- upset stomach
- stomach pain
- loss of appetite
If you experience any of the following symptoms, call your health care provider immediately:
- an increase or decrease in frequency of urination
- an increase or decrease in the amount of urine
- an increase in thirst
- sore throat
- pain at the injection site
- muscle twitching
- pain or numbness in the hands or feet
- tingling sensation around the mouth
- unusual tiredness or weakness
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].
Storing your medication
- Your health care provider probably will give you several days supply of foscarnet. Store foscarnet at room temperature and out of direct light.
Store your medication only as directed. Make sure you understand what you need to store your medication properly.
Keep your supplies in a clean, dry place when you are not using them, and keep all medications and supplies out of reach of children. Your health care provider will tell you how to throw away used needles, syringes, tubing, and containers to avoid accidental injury.
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Signs of infection
If you are receiving foscarnet in your vein or under your skin, you need to know the symptoms of a catheter-related infection (an infection where the needle enters your vein or skin). If you experience any of these effects near your intravenous catheter, tell your health care provider as soon as possible: