Do not use this medication if you are allergic to foscarnet.
Before using foscarnet, tell your doctor if you are allergic to any drugs, or if you have:
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kidney disease;
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epilepsy or other seizure disorder;
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a history of head injury or brain tumor;
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heart disease;
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a nerve disorder;
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low levels of calcium, magnesium, or potassium in your blood; or
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any other type of electrolyte imbalance.
If you have any of these conditions, you may not be able to use foscarnet, or you may need dosage adjustments or special tests during treatment.
FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
It is not known whether foscarnet passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
Foscarnet is given as an injection through a needle placed into a vein. The medicine must be given slowly through an IV infusion pump, and can take up to 2 hours to complete.
You may be given instructions on how to inject your medicine at home. Do not use this medicine at home if you do not fully understand how to give the injection and properly dispose of needles and other items used in giving the medicine.
With each foscarnet injection, you may be given IV fluids to keep you from getting dehydrated.
Foscarnet is usually given for 2 to 3 weeks. Your doctor may occasionally change your dose to make sure you get the best results from this medication.
You may need to mix foscarnet with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medication.
Foscarnet should be clear and colorless. Do not use the medication if it has changed colors or has any particles in it. Call your doctor for a new prescription.
To be sure this medication is not causing harmful effects, your blood will need to be tested on a regular basis. Your kidney function may also need to be tested, and you may also need regular eye exams. Do not miss any scheduled visits to your doctor.
Store foscarnet at room temperature away from very hot or very cold temperature.
Use the medication as soon as you remember the missed dose. If it is almost time for your next dose, skip the missed dose and use the medicine at your next regularly scheduled time. Do not use extra medicine to make up the missed dose.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using foscarnet and call your doctor at once if you have any of these serious side effects:
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urinating less than usual or not at all;
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dry mouth, increased thirst, drowsiness, restless feeling, confusion, nausea, vomiting, increased urination, muscle pain or weakness, fast heart rate, feeling light-headed, fainting, or seizure (convulsions);
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fever, chills, body aches, flu symptoms;
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pale skin, easy bruising or bleeding;
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numbness or tingling around your mouth or in your hands or feet;
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restless muscle movements in your eyes, tongue, jaw, or neck;
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trouble breathing; or
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pain or burning when you urinate.
Keep using foscarnet and talk with your doctor if you have any of these less serious side effects:
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anxiety, confusion, depressed mood;
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nausea, stomach pain, vomiting;
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headache, dizziness;
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cough;
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increased sweating;
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skin rash;
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problems with vision;
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weakness, tired feeling;
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joint or muscle pain; or
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pain or swelling where the injection was given.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
Foscarnet is not a cure for CMV, and the virus may progress during or after treatment.
Before using foscarnet, tell your doctor if you have kidney disease, a seizure disorder, heart disease, a nerve disorder, or an electrolyte imbalance such as low calcium, potassium, or magnesium.
To be sure this medication is not causing harmful effects, your blood will need to be tested on a regular basis. Your kidney function may also need to be tested, and you may also need regular eye exams. Do not miss any scheduled visits to your doctor.
Stop using foscarnet and call your doctor at once if you urinate less than usual or not at all, or if you have numbness or tingling around your mouth, uncontrolled muscle movements, or pain or burning when you urinate.
There are many other medicines that can cause kidney damage or lower calcium levels and should not be used together with foscarnet. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor or other healthcare provider who treats you.
Avoid getting this medicine in your eyes, as it may cause burning or irritation. If it does get into your eyes rinse with water and call your doctor.
Before using foscarnet, tell your doctor if you are using any of the following drugs:
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amphotericin B (Abcelet, Ambisome, Fungizone);
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cancer medications;
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digoxin (Lanoxin).
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diuretics (water pills);
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laxatives, bowel stimulants;
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leucovorin;
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pentamidine (Nebupent, Pentam);
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IV phenytoin (Dilantin);
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promethazine (Compazine (Procot);
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IV sedatives such as diazepam (Valium) or midazolam (Versed);
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tacrolimus (Prograf);
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trimethoprim and sulfamethoxazole (Bactrim I.V., Septra I.V.);
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antibiotics such as capreomycin (Capastat), rifampin (Rifadin, Rimactane, Rifater), vancomycin (Vancocin, Vancoled); or
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antiviral medicines such as acyclovir (Zovirax), adefovir (Hepsera), cidofovir (Vistide), or ganciclovir (Cytovene).
Many of these other drugs can damage the kidneys, or lower calcium levels in the body. If you are using any of these drugs, you may not be able to use foscarnet, or you may need dosage adjustments or special tests during treatment.
There may be other drugs not listed that can affect foscarnet. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
Seek emergency medical attention if you think you have used too much of this medicine.
Symptoms of a foscarnet overdose may include numbness or tingling, thirst, drowsiness, confusion, urinating more or less than usual, muscle pain or weakness, fast heart rate, feeling light-headed, fainting, or seizure (convulsions).
