Diflucan Side Effects

Generic Name: fluconazole

Note: This page contains information about the side effects of fluconazole. Some of the dosage forms included on this document may not apply to the brand name Diflucan.

Not all side effects for Diflucan 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 fluconazole: oral capsule, oral powder for suspension, oral tablet

In addition to its needed effects, some unwanted effects may be caused by fluconazole (the active ingredient contained in Diflucan). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking fluconazole:

  • Abdominal or stomach pain
  • chills
  • clay-colored stools
  • cough
  • dark urine
  • diarrhea
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • fever
  • general feeling of tiredness or weakness
  • headache
  • hives, itching, or skin rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • loss of appetite
  • nausea and vomiting
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • stomach pain, continuing
  • tightness in the chest
  • unpleasant breath odor
  • unusual tiredness or weakness
  • upper right abdominal or stomach pain
  • vomiting of blood
  • yellow eyes and skin
Incidence not known
  • Black, tarry stools
  • blistering, peeling, or loosening of the skin
  • chest pain or discomfort
  • convulsions
  • decreased urine
  • dry mouth
  • fainting
  • hoarseness
  • increased thirst
  • irregular or slow heart rate
  • joint or muscle pain
  • loss of bladder control
  • lower back or side pain
  • mood changes
  • muscle pain or cramps
  • muscle spasm or jerking of all extremities
  • numbness or tingling in the hands, feet, or lips
  • painful or difficult urination
  • pale skin
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • sudden loss of consciousness
  • swollen glands
  • unusual bleeding or bruising

If any of the following symptoms of overdose occur while taking fluconazole, get emergency help immediately:

Symptoms of overdose
  • Fearfulness, suspiciousness, or other mental changes
  • seeing, hearing, or feeling things that are not there

Some of the side effects that can occur with fluconazole may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common
  • Acid or sour stomach
  • belching
  • change in taste or bad, unusual, or unpleasant (after) taste
  • heartburn
  • indigestion
  • stomach discomfort or upset
Incidence not known
  • Hair loss or thinning of the hair

For Healthcare Professionals

Applies to fluconazole: intravenous solution, oral powder for reconstitution, oral tablet


Fluconazole is generally well tolerated. Changes in renal and hematological function test results and hepatic abnormalities have been reported during treatment with fluconazole (the active ingredient contained in Diflucan) and comparative agents in some patients, primarily those with serious underlying diseases such as AIDS and cancer; however, the clinical significance and relationship to therapy is uncertain.

During clinical trials of single dose therapy, side effects possibly related to fluconazole were reported in 26% of patients. In patients receiving active comparative agents, the incidence was 16%. The most common side effects reported in patients receiving a single 150 mg dose of fluconazole for vaginitis were headache, nausea, and abdominal pain. Most side effects were of mild to moderate severity.

During clinical trials of multiple dose therapy, side effects were reported in 16% of patients. Treatment discontinuation occurred in 1.5% and 1.3% of patients due to adverse clinical events and laboratory test abnormalities, respectively. Clinical adverse events were reported more frequently in HIV patients than in non-HIV patients (21% versus 13%); however, the patterns in HIV and non-HIV patients were similar.

Nervous system

Rare cases of seizures have been reported, but a causal relationship was difficult to establish, since some of these patients had cryptococcal meningitis or severe underlying disease. Nonetheless, at least one case of seizure following a 100 mg oral dose has been reported.

Nervous system side effects have included headache (up to 13%) and dysesthesias. Seizures, dizziness, insomnia, paresthesia, somnolence, tremor, and vertigo have been reported during postmarketing experience.


Gastrointestinal side effects have included nausea (up to 7%), abdominal pain (up to 6%), diarrhea (up to 3%), vomiting (1.7%), dyspepsia (1%), taste perversion (1%), anorexia, and general abdominal discomfort. Dry mouth, dyspepsia, vomiting, and taste perversion have been reported during postmarketing experience.


Hepatic side effects have included rare cases of serious hepatic reactions ranging from mild transient transaminase elevations to clinical hepatitis, cholestasis, and fulminant hepatic failure (including fatalities). Transient hepatic reactions (including hepatitis and jaundice), elevated liver function tests (transient and asymptomatic), hepatitis, cholestatic jaundice, and fatal hepatic necrosis have been reported. Serum transaminase elevations (greater than 8 times the upper limit of normal; approximately 1%) and statistically significant increases in AST (SGOT) have been reported. Cholestasis and hepatocellular damage have been reported during postmarketing experience.

Fatal hepatic reactions have occurred primarily in patients with serious underlying medical conditions (primarily AIDS or malignancy) and often taking multiple concomitant medications. One reported patient with AIDS experienced acute hepatic necrosis and hepatic failure approximately 3 weeks after beginning fluconazole therapy.

Transient hepatic reactions have been reported in patients with no other identifiable risk factors. Liver function returned to baseline following fluconazole discontinuation.

Serum transaminase elevations have been reported primarily in patients with serious underlying medical conditions (primarily AIDS or malignancy) and often taking multiple concomitant medications, including agents known to be hepatotoxic.


Dermatologic side effects have included skin rash (1.8%) and reversible alopecia. Exfoliative skin disorders (including fatalities) have been reported rarely. Acute generalized exanthematous pustulosis, drug eruption, increased sweating, exfoliative skin disorders (including Stevens-Johnson syndrome and toxic epidermal necrolysis), and alopecia have been reported during postmarketing experience.

Reversible alopecia has been associated with long-term (2 months or longer) therapy.

In patients with serious underlying diseases (primarily AIDS and malignancy), exfoliative skin disorders have rarely resulted in a fatal outcome.


Hypersensitivity side effects have rarely included angioedema and anaphylactic reaction. Rare cases of exfoliative dermatitis and ulcerative eruptions consistent with Stevens-Johnson syndrome have been reported in association with hypersensitivity reactions to fluconazole (the active ingredient contained in Diflucan) Anaphylaxis, generalized edema, stridor, hypotension, and fixed drug eruption have been reported. In rare cases, anaphylaxis (including angioedema, face edema, and pruritus) has been reported during postmarketing experience.

A 52-year-old female experienced a fixed drug eruption (FDE) when administered a single oral 400 mg dose of fluconazole therapy for extensive pityriasis versicolor. Within a 12-hour period, she noticed 3 oval, painful, eroded, pigmented patches over her trunk with diameters of 3 cm to 4 cm and erythematous halos. A clinical diagnosis of FDE caused by fluconazole therapy was made. The FDE was confirmed when the patient was rechallenged with an oral dose of fluconazole 25 mg.


Cardiovascular side effects have included prolongation of the QT interval on the electrocardiogram (ECG) and palpitations. QT prolongation and torsades de pointes have been reported during postmarketing experience.

Most reports of QT interval prolongation and torsades de pointes involved seriously ill patients with multiple confounding risk factors, such as structural heart disease, electrolyte abnormalities, and concomitant medications that may have been contributory.

An 11-year-old male with neurofibromatosis-1 presented to the hospital in septic shock secondary to a perforated gastric volvulus. After initial stabilization, the patient underwent total gastrectomy and multiple peritoneal lavages. Culture of peritoneal fluid showed infection with Candida albicans. Therapy was initiated with fluconazole 150 mg intravenously every 12 hours. After initiating fluconazole therapy, the patient developed QT prolongation and complex ventricular arrhythmia. Fluconazole was discontinued. Over the subsequent 36-hours, the patient remained in sinus rhythm except for one brief run of ventricular bigeminy. An ECG recorded 5 months after admission (and approximately 4 months after cessation of all QT-prolonging medications) showed sinus rhythm with normal heart rate and corrected QT interval.


Hematologic side effects have included anemia, leukopenia, neutropenia, agranulocytosis, and thrombocytopenia during postmarketing experience. Eosinophilia has been reported.

Anemia, eosinophilia, leukopenia, neutropenia, and thrombocytopenia have been reported, often in patients with severe deep fungal infections or underlying disease.

Spontaneous reports of anemia were more frequent in patients 65 years of age or older than in those between 12 and 65 years of age; however, there is a natural increase in the incidence of anemia in the elderly. A causal relationship to drug exposure could not be determined.


A 58-year-old female with a history of hypertension and cervical cancer experienced membranous nephropathy coincident with fluconazole (the active ingredient contained in Diflucan) therapy. The patient presented with increasing generalized edema accompanied by nausea and indigestion for 3 weeks. Clinical findings showed the patient had stage I membranous nephropathy. At initial presentation, the patient's medication history included amlodipine, hydrochlorothiazide, metoclopramide, and levosulpiride. She did not admit to taking fluconazole therapy. Five months after the initial presentation, the patient returned with reports of increasing pedal edema. At that point, the patient admitted to taking fluconazole once weekly for tinea pedis. Off fluconazole, the patient went into complete remission.

Spontaneous reports of acute renal failure were more frequent in patients 65 years of age or older than in those between 12 and 65 years of age; however, there is a natural increase in the incidence of renal failure in the elderly. A causal relationship to drug exposure could not be determined.

Renal side effects have included at least one case of membranous nephropathy. Acute renal failure has been reported during postmarketing experience.


Metabolic side effects have included hypercholesterolemia, hypertriglyceridemia, and hypokalemia during postmarketing experience.


Other side effects have included fever, asthenia, fatigue, and malaise during postmarketing experience.


Respiratory side effects have included respiratory disorders.


Musculoskeletal side effects have included back and joint pain. Finger stiffness has been reported, although the association to therapy was questionable. Myalgia has been reported during postmarketing experience.

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