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Drug side effects

fluconazole Side Effects

The reactions most often reported to the FDA for fluconazole (also sold as Diflucan), with demographics, serious outcomes, and reporting trends.

Data updated 2026-05-15

67,703
FAERS reports

Data from the FDA Adverse Event Reporting System (FAERS), 1999 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.

The most commonly reported side effects of fluconazole come from 67,703 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.

This page analyzes 67,703 reports to the FDA Adverse Event Reporting System (FAERS) for fluconazole (Diflucan): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.

Total Reports

67,703

Reports Mentioning Death

12,178

18.0% of reports — not proof the medicine caused the death

Hospitalizations

29,753

43.9% of reports

Top Indication

Product Used For Unknown Indication

Most Reported Adverse Reactions

PYREXIA
4,121
NAUSEA
3,697
DIARRHOEA
3,538
FATIGUE
3,151
PAIN
3,123
DRUG INTERACTION
2,934
PNEUMONIA
2,851
HEADACHE
2,807
FEBRILE NEUTROPENIA
2,661
RASH
2,404
DYSPNOEA
2,362
VOMITING
2,329
DEATH
2,137
ACUTE KIDNEY INJURY
2,134
ANAEMIA
2,070
THROMBOCYTOPENIA
2,001
SEPSIS
1,953
NEUTROPENIA
1,866

Who Reports Side Effects

Gender Distribution

Female 35,493 (57%)
Male 26,014 (42%)
Unknown 318

Age Distribution

0-17 4,061 (8%)
18-44 11,151 (23%)
45-64 17,068 (35%)
65-74 9,627 (20%)
75+ 6,446 (13%)

Reporting Trend by Year

1999 2025

Reactions in Death Reports

Top reactions reported in 12,178 reports where death was an outcome. These are voluntarily reported and do not establish causation.

Reaction Reports
DEATH 2,135
PNEUMONIA 1,048
SEPSIS 1,046
PYREXIA 883
SEPTIC SHOCK 708
THROMBOCYTOPENIA 696
RESPIRATORY FAILURE 672
FEBRILE NEUTROPENIA 633
ANAEMIA 596
MULTIPLE ORGAN DYSFUNCTION SYNDROME 585
RENAL FAILURE 575
DIARRHOEA 572
NEUTROPENIA 520
DYSPNOEA 478
HYPOTENSION 461
DISEASE PROGRESSION 456
NAUSEA 456
PANCYTOPENIA 444

Reactions in Hospitalization Reports

Top reactions in 29,753 reports where hospitalization was an outcome.

Reaction Reports
PYREXIA 2,613
PNEUMONIA 2,090
DIARRHOEA 2,002
NAUSEA 1,925
FEBRILE NEUTROPENIA 1,915
DRUG INTERACTION 1,518
ANAEMIA 1,488
VOMITING 1,444
DYSPNOEA 1,426
PAIN 1,354
ACUTE KIDNEY INJURY 1,323
SEPSIS 1,305
FATIGUE 1,281
NEUTROPENIA 1,196
THROMBOCYTOPENIA 1,161
ASTHENIA 1,099
ABDOMINAL PAIN 1,042
HEADACHE 1,019

Compare fluconazole vs acyclovir →

What the FAERS Data Reveals About fluconazole Side Effects

The FDA Adverse Event Reporting System (FAERS) contains 67,703 voluntary reports linked to fluconazole and its brand equivalents (Diflucan), spanning 1999 through 2025. Of those, 12,178 (18.0%) listed death as an outcome and 29,753 (43.9%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.

Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 57% were female and 42% male; age distribution skews toward 45-64, with 17,068 reports in that bracket. The single most reported reaction is pyrexia with 4,121 submissions, followed by nausea and diarrhoea.

How to read these numbers

FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice, speak with a licensed clinician about any side-effect concerns.