In the U.S.—

• Antiviral, ophthalmic

Fomivirsen ( foe-MI-vir-sen) is an antiviral medicine that is injected into the eye (intravitreal). It is used to treat a serious condition called cytomegalovirus (CMV) retinitis in persons who have acquired immune deficiency syndrome (AIDS). Fomivirsen will not cure this eye infection, but it may help to keep the symptoms from becoming worse.

This medicine is available only with your doctor's prescription, in the following dosage form:

Parenteral-Local
• Intravitreal injection (injection in the eye) (U.S.)

In deciding to use a medicine, the risks of using the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For fomivirsen, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to fomivirsen. Also tell your health care professional if you are allergic to any other substances, such as certain preservatives.

Pregnancy—Studies on effects in pregnancy have not been done in either humans or animals. Before being treated with this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether fomivirsen injected into the eye passes into breast milk. Discuss with your doctor whether or not you should breast-feed while you are being treated with this medicine.

Children—Studies with this medicine have been done only in adult patients and there is no specific information comparing use of fomivirsen in children with use in other age groups.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of fomivirsen in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking fomivirsen, it is especially important that your health care professional know if you are receiving any of the following:

• Cidofovir injection (e.g., Vistide)—Possibility of increased eye inflammation

This medicine will not cure CMV retinitis, although it may help keep it from getting worse. In addition, it will not help other symptoms of CMV (for example, in the lungs or colon).

Dosing—

The dose of fomivirsen may be different for different patients. The following information includes only the average doses of fomivirsen.

• For parenteral-local dosage form (ophthalmic injection):
  • For CMV retinitis:
    • Adults—The usual starting dose is 330 micrograms injected into the eye once every other week for two doses. Then the same dose is used once every four weeks for as long as it is needed.
    • Children—Use and dose must be determined by your doctor.

It is very important that your doctor check your progress at regular visits to make sure the medicine is working properly and to watch for unwanted effects.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Abnormal vision;  blurred vision;  change in how colors look;  decreased vision or other changes in vision;  eye pain;  redness of eye;  seeing flashes or sparks of light;  seeing floating spots before eyes;  sensitivity of eye to light;  veil or curtain appearing across part of vision;  watering of eye 
  
  

• Less common
  • Decreased ability to see to the side when looking straight ahead ;  itching, redness, or soreness at place of injection ;  pain on moving the eye;  soreness of eye;  swelling of the eye 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Abdominal or stomach pain;  diarrhea ;  headache;  nausea;  skin rash;  vomiting;  weakness 
  
  

• Less common
  • Back pain;  cough;  dizziness;  loss of appetite;  sweating;  tightness in chest;  weight loss 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.