Foscavir Side Effects
Generic Name: foscarnet
Note: This page contains information about the side effects of foscarnet. Some of the dosage forms included on this document may not apply to the brand name Foscavir.
Not all side effects for Foscavir may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
For the Consumer
Applies to foscarnet: intravenous solution
Along with their needed effects, medicines like foscarnet (the active ingredient contained in Foscavir) can sometimes cause serious side effects such as kidney problems; these are described below. Foscarnet may also decrease the amount of calcium in your blood, causing you to have a tingling sensation around your mouth, and pain or numbness in your hands and feet. If this occurs, especially while you are receiving the medicine, notify your health care professional immediately.
Along with its needed effects, foscarnet 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 immediately if any of the following side effects occur while taking foscarnet:More common
- Increased or decreased frequency of urination or amount of urine
- increased thirst
- Convulsions (seizures)
- fever, chills, and sore throat
- muscle twitching
- pain at place of injection
- pain or numbness in hands or feet
- tingling sensation around mouth
- unusual tiredness and weakness
- Sores or ulcers on the mouth or throat, penis, or vulva
Some side effects of foscarnet may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:More common
- Abdominal or stomach pain
- anxious feeling
- loss of appetite
- nausea and vomiting
- unusual tiredness or weakness
For Healthcare Professionals
Applies to foscarnet: intravenous solution
Renal impairment is the major toxicity of foscarnet (the active ingredient contained in Foscavir) The most frequent adverse events reported during clinical trials included fever (65%), nausea (47%), anemia (33%), diarrhea (30%), abnormal renal function (27%), vomiting (26%), headache (26%), and seizures (10%). Adverse events classified as severe included death (14%), abnormal renal function (14%), bone marrow suppression (10%), anemia (9%), and seizures (7%).
Renal side effects have included dose-related renal impairment, which is the major toxicity of foscarnet (the active ingredient contained in Foscavir) and has occurred in up to 33% of patients. Acute renal failure, serum creatinine elevations greater than or equal to 2.9 mg/dL, renal tubular acidosis, and renal calculi have also been reported.
Renal adverse effects are due to acute tubular necrosis, possibly from deposition of foscarnet crystals in the renal tubules and capillaries. Renal failure as well as tubular dysfunction such as nephrogenic diabetes insipidus may result. The development of nephrotoxicity was most common during the third week of therapy in one study.
Nephrotoxicity is reversible in patients with previously adequate renal function. Hydration with 2.5 liters of normal saline per day beginning the day before foscarnet therapy has been shown to decrease the incidence of nephrotoxicity.
Gastrointestinal side effects have included nausea (47%), vomiting (26%), diarrhea (30%), anorexia (5% or more), and abdominal pain (5% or more). Constipation, dysphagia, dyspepsia, rectal hemorrhage, dry mouth, melena, flatulence, ulcerative stomatitis, and pancreatitis have been reported in 1% to 5% of patients. An isolated case of uvula and esophageal ulceration has been reported.
Hematologic side effects have included anemia (33%), neutropenia (17%), granulocytopenia (5% or more), and leukopenia (5% or more). Thrombocytopenia, platelet abnormalities, thrombosis, blood cell abnormalities, and lymphadenopathy have been reported in 1% to 5% of patients.
Nervous system side effects have included headache (26%) and seizures (10%). Paresthesia, dizziness, involuntary muscle contractions, hypoesthesia, neuropathy, and grand mal seizures have been reported in greater than or equal to 5% of patients. Tremor, ataxia, dementia, stupor, generalized spasms, sensory disturbances, meningitis, aphasia, abnormal coordination, leg cramps, and EEG abnormalities have been reported in 1% to 5% of patients. Risk factors for foscarnet-related seizures include low neutrophil count, central nervous system disease, impaired renal function, and electrolyte and metabolic abnormalities.
Metabolic disturbances have occurred in 15% to 40% of patients treated with foscarnet (the active ingredient contained in Foscavir) and include hypocalcemia, hypomagnesemia, hypokalemia, hyponatremia secondary to nephrogenic diabetes insipidus, and hypo- and hyperphosphatemia. More severe metabolic abnormalities have resulted in tremors, twitches, arrhythmias, parenthesis, and seizures. Dehydration, hypoproteinemia, syndrome of inappropriate antidiuretic hormone secretion (SIADH), and increased amylase and creatinine phosphokinase have been reported in less than 1% of patients. Hypercalcemia has also been reported.
Serum ionized calcium concentrations have been shown to decrease acutely in a dose-dependent manner following an infusion of foscarnet. Total calcium and phosphate levels were not significantly affected. Foscarnet is believed to complex with ionized calcium.
Other side effects have included fever (65%), and fatigue, rigors, asthenia, malaise, pain, infection, and sepsis in greater than or equal to 5% of patients.
Local side effects have included injection site pain and inflammation.
Dermatologic side effects have included rash and increased sweating in greater than or equal to 5% of patients. Pruritus, skin ulceration, seborrhea, erythematous rash, maculopapular rash, and skin discoloration have been reported in 1% to 5% of patients. Erythema multiforme, toxic epidermal necrolysis, eosinophilic folliculitis, and Stevens-Johnson syndrome have been reported during postmarketing experience.
Cardiovascular side effects have included hypertension, palpitations, ECG abnormalities, sinus tachycardia, first degree AV block, nonspecific ST-T segment changes, hypotension, flushing, cerebrovascular disorder in 1% to 5% of patients. Cardiac arrest, coma, and other cardiovascular complications have been reported in less than 1% of patients.
Reversible cardiac dysfunction has been reported in one patient receiving foscarnet, who experienced shortness of breath, increased heart rate, and pulmonary edema, which reoccurred upon rechallenge. Serum electrolytes were within normal limits. Ventricular arrhythmia and QT interval prolongation have been reported during postmarketing experience.
Hepatic side effects have included abnormal hepatic function, abnormal A-G ratio, increased SGPT, and increased SGOT in 1% to 5% of patients. Increased gamma glutamyl transpeptidase has been reported during postmarketing experience.
Musculoskeletal side effects have included arthralgia and myalgia in 1% to 5% of patients. Myopathy, myositis, muscle weakness, and rhabdomyolysis have been reported during postmarketing experience.
Oncologic side effects have included lymphoma-like disorder and sarcoma in 1% to 5% of patients.
Respiratory side effects have included coughing and dyspnea in greater than or equal to 5% of patients. Pneumonia, sinusitis, pharyngitis, rhinitis, respiratory disorders, respiratory insufficiency, pulmonary infiltration, stridor, pneumothorax, hemoptysis, and bronchospasm have been reported in 1% to 5% of patients.
Psychiatric side effects have included confusion and anxiety in greater than or equal to 5% of patients. Insomnia, somnolence, nervousness, amnesia, agitation, aggressive reaction, and hallucination have been reported in 1% to 5% of patients.
Ocular side effects have included eye abnormalities, eye pain, and conjunctivitis in 1% to 5% of patients.
Penile ulcerations have been reported to occur after a median of 11 days of induction therapy and 30 days of maintenance therapy, and heal within six days of drug discontinuation. Ulceration has been reported more often in uncircumcised patients. Vulvar erosion may also occur but is less common. Penile ulceration is thought to result from local irritation by high concentrations of foscarnet (the active ingredient contained in Foscavir) in the urine. Good hygiene may help reduce irritation.
Genitourinary side effects have included albuminuria, dysuria, polyuria, urethral disorder, urinary retention, urinary tract infections, and nocturia in 1% to 5% of patients, and hematuria in less than 1% of patients. Local irritation and ulceration of penile epithelium in male patients and vulvovaginal ulceration in a female patient have also been reported.
Foscarnet accumulates in teeth and bones of growing animals. Tooth enamel development has been affected in rats receiving foscarnet (the active ingredient contained in Foscavir)
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