Foscarnet (By injection)Foscarnet (fos-KAR-net)Treats cytomegalovirus (CMV) eye infection in patients with AIDS. Also treats herpes simplex virus infections in the nose, mouth, vagina, or rectum.Brand Name(s): Foscavir, Foscavir NovaplusThere may be other brand names for this medicine.When This Medicine Should Not Be Used: This medicine is not right for everyone. You should not receive it if you had an allergic reaction to foscarnet.How to Use This Medicine: InjectableYour doctor will prescribe your dose and schedule. This medicine is given through a needle placed in a vein. This medicine is given slowly, so the needle will stay in place for 1 to 2 hours or longer. A nurse or other health provider will give you this medicine. Missed dose: Call your doctor or pharmacist for instructions. Drugs and Foods to Avoid: Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.Some medicines can affect how foscarnet works. Tell your doctor if you are using any of the following:Acyclovir, amphotericin B, cyclosporine, methotrexate, pentamidine, or tacrolimus Aminoglycoside antibiotic Diuretic (water pill) Medicine to treat depression Medicine to treat heart rhythm (including amiodarone, dofetilide, procainamide, quinidine, sotalol) Medicine to treat an infection Phenothiazine medicineWarnings While Using This Medicine: Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, anemia, heart disease, a history of seizures, or if you are on a low sodium diet. Do not breastfeed. You can spread HIV or AIDS to your baby through your breast milk. This medicine may cause the following problems:Kidney damage Seizures Electrolyte imbalances in your blood, such as low calcium, potassium, or magnesium Heart rhythm problem (such as QT prolongation) This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Drink extra fluids so you will urinate more often and help prevent kidney problems. Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments. You will need regular eye exams if you are receiving this medicine for a CMV eye infection.Possible Side Effects While Using This Medicine: Call your doctor right away if you notice any of these side effects:Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing Decrease in how much or how often you urinate Dry mouth, increased thirst, muscle cramps, nausea, vomiting Fast, pounding, or uneven heartbeat Fever chills, cough, sore throat, body aches Muscle cramps or spasms, confusion Pain, tingling, or numbness in your hands or feet or tingling around your mouth Seizures Unusual bleeding, bruising, tiredness, or weaknessIf you notice these less serious side effects, talk with your doctor:Diarrhea Headache Irritation or sores in your genital area Pain, itching, burning, swelling, or a lump under your skin where the needle is placedIf you notice other side effects that you think are caused by this medicine, tell your doctorCall your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 Last Updated: 6/6/2024