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Foscarnet Side Effects

The most commonly reported side effects of foscarnet include off label use, drug resistance, and cytomegalovirus infection, based on 4,000 FDA adverse event reports from 2004 to 2025. 14.5% of reports found the drug to be ineffective.

Foscarnet side effects

Percentages show how often each reaction appears relative to total reports for foscarnet.

1
Off Label Use21.3%853
2
Drug Ineffective14.5%580
3
Drug Resistance11.5%461
4
Cytomegalovirus Infection8.6%344
5
Acute Kidney Injury8.2%326
6
Pancytopenia5.9%238
7
Pathogen Resistance5.9%235
8
Renal Impairment5.7%229
9
Cytomegalovirus Infection Reactivation5.6%225
10
Nephropathy Toxic5.2%207
11
Cytomegalovirus Viraemia5.1%204
12
Neutropenia4.2%166
13
Pyrexia4.0%161
14
Encephalitis Cytomegalovirus3.8%150
15
Myelosuppression3.8%150

These are voluntary reports and do not establish that foscarnet caused these reactions.

Report severity

96.9%Serious3,876 reports
36.4%Hospitalizations1,454 reports
32.3%Fatal1,292 reports

Seriousness is determined by the reporter, not by OpenClaim.

Foscarnet drug interactions

Other drugs that appear in adverse event reports alongside foscarnet. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Ganciclovir35.4%1,416
2
Tacrolimus14.1%564
3
Cyclosporine13.2%529
4
Mycophenolate11.1%442
5
Cyclophosphamide10.7%428
6
Fludarabine-phosphate9.8%394
7
Methylprednisolone7.7%309
8
Rituximab7.2%288
9
Acyclovir6.6%263
10
Prednisone6.3%254
11
Cidofovir6.1%244
12
Busulfan5.9%235
13
Methotrexate5.0%198
14
Prednisolone4.6%183
15
Amphotericin-b4.4%176

Taken alongside

1
Ganciclovir19.8%792
2
Acyclovir10.8%431
3
Methylprednisolone10.3%412
4
Tacrolimus10.2%407
5
Prednisone9.9%396
6
Mycophenolate9.2%369
7
Cyclosporine8.1%322
8
Vancomycin7.2%287
9
Fludarabine-phosphate7.1%286
10
Fluconazole7.1%285
11
Sulfamethoxazole6.9%277
12
Meropenem6.4%256
13
Trimethoprim5.7%229
14
Furosemide5.6%224
15
Letermovir5.3%214

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports foscarnet side effects

37.4% of foscarnet adverse event reports involve female patients and 50.8% involve male patients. The largest age group is adult at 65%. These figures reflect who reports side effects, not underlying risk.

Sex

Female37.4%
Male50.8%
Unknown11.8%

Age group

< 23.7%
2–1110.2%
12–176.6%
18–6464.7%
65+14.8%

What is foscarnet used for

Conditions and purposes for which patients were taking foscarnet when the adverse event was reported.

Abdominal DiscomfortAccidental Exposure To ProductAcute Graft Versus Host DiseaseAcute Lymphocytic LeukaemiaAcute Myeloid LeukaemiaAdenovirus InfectionAdrenalitisAdverse EventAntibiotic TherapyAntifungal ProphylaxisAntiretroviral TherapyAntiviral ProphylaxisAntiviral TreatmentAcute Graft Versus Host DiseaseAcute Lymphocytic Leukaemia

Showing 15 of 331 indications

Foscarnet brand names and reporting trend

Foscarnet is sold under the brand name Foscavir.

Brand names

Foscavir3,954

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking foscarnet with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.