What is Foscarnet?
Foscarnet, an antiviral medication, prevents the spread of certain viruses in your body. Foscarnet can be used to treat cytomegalovirus retinitis (CMV) in people with AIDS. Foscarnet can also be used to treat the herpes simplex (HSV) virus in patients with a weakened immune system. Foscarnet for HSV is typically given after trying other antiviral medicines without success. Foscarnet does not cure CMV or HSV. Your virus can progress during or even after treatment. Foscarnet can be used in other ways not mentioned in this guide.
Side effects of Foscarnet
If you experience any of the following signs of an allergic reaction: difficulty breathing, hives or swelling of the face, lips or throat. Seek medical assistance immediately.
Foscarnet can cause serious side effects. If you experience:
- Pain or burning after urinating;
- A seizure (convulsions);
- Headache with severe chest pain, dizziness, and fainting; fast or pounding pulsebeats
- Low potassium levels may result in constipation, numbness/tingling sensations, fatigue, muscle weakness, slower heart rates and fainting;
- Low red blood cells, or anemia, can cause pale skin, a feeling of being light-headed, a rapid heartbeat, and difficulty concentrating.
- Low calcium—numbness, tingling, or rapid heartbeat or heart rate; muscle contraction or tightness; or overactive reflexes.
- Low potassium—constipation, numbness or tingling, tiredness, muscle weakness, slow heart rate, fainting;
- Kidney problems: little or no urinating; painful or difficult urination; swelling of the feet or ankles; and feeling tired or short of breath.
Foscarnet can cause irritation in the urine. Also, you may develop ulcers or sores around the urethra. This is where urine exits your bladder. While receiving this medication, drink plenty of water and keep your genital region clean.
Side effects of foscarnet include:
- Fever, flu-like symptoms;
- Nausea, vomiting, diarrhea;
- Chest pain, back pain;
There may be other side effects. For medical advice regarding side effects, always contact your physician first. For reporting purposes, call the FDA's Hotline at 1-800-FDA-1088 to report these.
Warnings
Foscarnet may harm your kidneys. Foscarnet can cause kidney damage. You will need to test your kidney function as well as electrolytes such as potassium, sodium, magnesium, and phosphorus. When foscarnet is injected too quickly, it can have dangerous or unwanted effects.
Before you take this drug
If you have an allergy to foscarnet, then it is best not to use the product.
Tell your doctor about any of the following to ensure that foscarnet will be safe for you:
- Kidney disease
- Heart disease. Heart rhythm disorder
- Personal or family history long-qt syndrome
- An electrolyte imbalance is a low level of potassium, calcium, or magnesium in the blood.
- Epilepsy or another seizure disorder
- If you're on a diet low in salt,
Foscarnet has not been shown to cause harm to an unborn baby. Please inform your healthcare provider if you are planning or pregnant or considering becoming pregnant. Foscarnet does not pass into breast milk and it remains unknown whether this medication could harm a nursing baby. Therefore, this medicine should not be taken while breastfeeding.
How to take Foscarnet?
Please follow all the instructions on the prescription label. Your doctor may occasionally alter your dosage. Use this medication only as prescribed. Do not exceed the recommended dose or use it for longer. Foscarnet can be injected through an IV with an infusion pump. A catheter is inserted into the vein to allow the medicine to enter the body. You will be shown how to use the infusion pump by a healthcare provider. You should not inject foscarnet yourself if you don't know how to properly give an injection or dispose of needles, IV tubes, and other items that were used to administer the medicine. If you are dehydrated, IV fluids may be administered to prevent you from becoming dehydrated. It may be necessary to dilute foscarnet before use. You should know how to mix and store your injections if you use them at home. Foscarnet should not be given with other medications in the same IV. Foscarnet must be colorless and clear. Shake the medicine gently if it appears to be separated. If the color of your medicine has changed or if there are particles in the medication, do not use it. For new medication, call your pharmacist.
It can take two hours or more to inject the medicine. Foscarnet can have dangerous side effects if injected too quickly. Foscarnet is usually given for two to three weeks. Be sure to abide by your doctor's recommendations. You may need to have regular eye examinations and tests of your electrolytes, potassium, sodium, magnesium, and phosphorus, while using foscarnet. Keep Foscarnet away from extreme temperatures.
What happens if I miss the dose?
If you forget to take a dose, call your doctor.
What happens if I overdose?
Call 1-800-222-1222 for poison help or seek immediate medical attention.
What should be avoided?
Foscarnet can cause irritation or burning in the eyes. If you do get it in your eyes, rinse them with water and contact your doctor. This medicine can impair your reactions or thinking. You should be careful when driving or doing anything else that requires alertness.
Interaction with other drug
Foscarnet may harm your kidneys. This effect can be increased if you use other medications, such as antivirals (antiviral drugs), chemotherapy, injected bacteria, medicine for bowel problems, medicine to prevent rejection of organ transplants, injectionable osteoporosis medicine, or some pain relievers and arthritis medicines. Notify your doctor immediately if you start taking any new medicines, or intend to discontinue any current ones.
- Anagrelide, cilostazol, donepezil, fluconazole, methadone, and ondansetron;
- Antibiotic or antifungal medicine such as azithromycin, ciprofloxacin, clarithromycin, erythromycin, fluconazole, levofloxacin (levofloxacin), moxifloxacin, pentamidine or telithromycin is used to treat infections.
- Cancer medicine: arsenic dioxide, oxaliplatin, and vandetanib
- An antidepressant—citalopram, escitalopram;
- Anti-malaria medication: chloroquine, halofantrine;
- Heart rhythm medicine: amiodarone, disopyramide, dofetilide, dronedarone, flecainide, ibutilide, procainamide, quinidine, and sotalol;
- Medicine to treat a psychiatric disorder—chlorpromazine, droperidol, haloperidol, pimozide, and thioridazine.
This list is incomplete. Foscarnet may interact with other drugs, such as prescription and OTC medications, vitamins, and herbal products. This medication guide does not list all possible interactions.
