Flucytosine Side Effects

Some side effects of flucytosine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to flucytosine: oral capsule

If you experience any of the following serious side effects, stop taking flucytosine and seek emergency medical attention or contact your doctor immediately:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);

• chest pain;

• yellowing of the skin or eyes;

• little or no urine;

• confusion or hallucinations;

• numbness or tingling; or

• hearing loss.

Other, less serious side effects may be more likely to occur. Continue to take flucytosine and talk to your doctor if you experience

• nausea, vomiting, decreased appetite, or diarrhea;

• a dry mouth;

• headache;

• sedation; or

• weakness or poor coordination.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to flucytosine: oral capsule

Gastrointestinal

Gastrointestinal side effects have included nausea, emesis, abdominal pain, diarrhea, anorexia, dry mouth, duodenal ulcer, gastrointestinal hemorrhage, enterocolitis, and ulcerative colitis.

Nausea is common at high doses, generally occurs in the first two weeks of therapy, and often resolves with time or temporary dose reduction. Diarrhea is often associated with cramps, occurs most frequently in the first two weeks of therapy, and frequently resolves with time or temporary dose reduction. One case has been reported of a patient on long-term therapy who developed diarrhea which did not resolve spontaneously. X-ray of the small bowel revealed ulceration and the ileocecal valve and distal ileum appeared edematous. Flucytosine was discontinued and the patient improved over the next two weeks.

Hepatic

Some patients experience significant increases in liver function tests and may develop signs and symptoms of hepatitis. Liver function test abnormalities generally resolve after discontinuation of flucytosine.

Hepatic side effects have included jaundice, hepatic dysfunction, bilirubin elevation, increased hepatic enzymes, and acute hepatic injury including hepatic necrosis with possible fatal outcome in debilitated patients.

Hematologic

Hematologic side effects have included anemia, agranulocytosis, aplastic anemia, eosinophilia, leukopenia, pancytopenia, thrombocytopenia, and fatal cases of bone marrow suppression.

Bone marrow suppression may range from isolated leukopenia or thrombocytopenia to pancytopenia. Often there is just mild leukopenia or thrombocytopenia which does not require discontinuation of the drug. In most cases the suppression is reversible following discontinuation of flucytosine therapy, but at least one case of fatal, irreversible marrow failure has occurred.

Hypersensitivity

Photosensitivity has been reported in one case of a patient receiving long-term flucytosine. The photosensitivity persisted for one year after completion of therapy.

A case of anaphylaxis has been reported. In that case, a patient who had hemophilia and AIDS was receiving flucytosine for oral candidiasis. Flucytosine therapy was started following 10 days of miconazole and the patient developed a fever, erythema, pruritus, tachycardia and hypotension requiring volume support. Rechallenge was attempted one week later with one tablet. The rechallenge resulted in the same signs and symptoms and ran a similar course.

Hypersensitivity side effects have included allergic reactions. Rashes have been reported rarely. At least one case of photosensitivity has been reported, in addition to a case of anaphylaxis.

Cardiovascular

A 34-year-old woman reported severe chest pain the day after completing a 2-day flucytosine therapy. Cardiac echography indicated septo-apico-lateral severe hypokinesia, with left ventricular ejection fraction less than 15%. Aggressive cardiac intensive care with positive inotropic agents, placement of an intra-aortic balloon pump counterpulsation, and milrinone along with continuous veno-venous hemodiafiltration were needed over the 2 weeks of hospitalization before restoration of her cardiovascular status. Patient has not shown further signs of heart problems during the 2 years since this event.

Cardiovascular side effects have included cardiac arrest, myocardial toxicity, and ventricular dysfunction. Cardiac toxicity with ST elevation has been reported in a 34-year-old woman, with no previous history of heart disease, the day after completing a 2-day flucytosine therapy.

Respiratory

Respiratory side effects have included dyspnea, chest pain, and respiratory arrest.

Dermatologic

Dermatologic side effects have included rash, pruritus, urticaria, photosensitivity, and Lyell's syndrome.

Genitourinary

Genitourinary side effects have included crystalluria.

Renal

Renal side effects have included azotemia, creatinine and BUN elevation, and renal failure.

Nervous system

Nervous system side effects have included ataxia, hearing loss, headache, paresthesia, parkinsonism, peripheral neuropathy, pyrexia, vertigo, sedation, and convulsions.

Psychiatric

Psychiatric side effects have included confusion, hallucinations, and psychosis.

Metabolic

Metabolic side effects have included hypoglycemia.

Other

Other side effects have included fatigue and weakness.

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