Foscarnet is used to treat eye problems caused by cytomegalovirus in individuals with AIDS. It is also used to treat Herpes simplex infections in individuals with weak immune systems that do not respond to other medications.


What is Foscarnet?

Foscarnet is an antiviral agent that works by inhibiting the growth and reproduction of viruses. In turn, it helps fight off infections caused by viruses.


How should Foscarnet be taken?

Foscarnet is administered by health care professionals via injection.  During treatment, it is advisable to drink plenty of fluids.


Side effects associated with Foscarnet

Foscarnet can cause kidney damage, convulsions and irritate the veins.


Among the other possible side effects of Foscarnet include the following:


  • Anxiety
  • Loss of appetite
  • Diarrhea
  • Dizziness
  • Headache
  • Nausea
  • Stomach ache
  • Sweating
  • Fatigue
  • Vomiting
  • Weakness


You should contact a doctor immediately if you experience:


  • Changes in the amount of urine produced
  • Convulsions
  • Rash
  • Urticaria
  • Itch
  • Difficulty breathing
  • Tightness in the chest
  • Swelling of the mouth, face, lips or tongue
  • Burning, numbness or tingling around the lips, hands or feet
  • Irritation or genital ulcers
  • Inability to control muscle movements
  • Shortness of breath
  • Mood swings
  • Confusion
  • Muscle cramps
  • Muscle pain or spasms
  • Fast or irregular heartbeat
  • Nausea or vomiting during pregnancy
  • Severe dizziness or faintness
  • Dry eyes or mouth
  • Increased thirst
  • Fever, chills, cough, sore throat and flu-like symptoms of an ongoing infection
  • Bloody urine
  • Urination problems
  • Excessive weight gain
  • Vision problems
  • Unusual tiredness or weakness


Contraindications and warnings associated with the use of Foscarnet

Foscarnet should not be taken if you suffer from certain heart problems, if you are on dialysis or if you are on a low sodium diet.


Before starting treatment with Foscarnet, it is important to tell your doctor if:


  • You have any allergies to the active substance, its excipients or any other drugs or food
  • You are taking any other medications, herbal remedies or supplements. Mentioning in particular: Pentamidine, diuretics, acyclovir, antibiotics, cyclosporin, amphotericin B, methotrexate, ritonavir, saquinavir, tacrolimus and drugs that can damage the liver or alter the levels of calcium in the blood
  • You are suffering (or have suffered) from central nervous system problems, abnormal levels of electrolytes in the blood (such as calcium, phosphate, magnesium or potassium), heart or kidney problems, dehydration, blood disorders (such as anemia or low white blood cells) or convulsions
  • You are pregnant or breast-feeding


Foscarnet can interfere with the ability to drive or operate dangerous machinery because it can trigger dizziness.  Alcohol may exacerbate this side effect.