Nizoral (Ketoconazole)

Uses

Ketoconazole tablets (oral ketoconazole) are used for the treatment of certain serious systemic fungal infections only when other effective antifungal therapy is not available or not tolerated and when the potential benefits are considered to outweigh the potential risks.

According to US prescribing information, ketoconazole tablets are indicated for the treatment of the following systemic fungal infections in patients who have failed or are intolerant to other therapies: blastomycosis, coccidioidomycosis, histoplasmosis, chromomycosis (chromoblastomycosis), and paracoccidioidomycosis.

The drug should not be used for initial therapy in severe, life-threatening infections. Because cerebrospinal fluid (CSF) concentrations are unpredictable following oral administration, ketoconazole tablets should not be used to treat CNS fungal infections (including fungal meningitis). Close follow-up during and after therapy is recommended.

Blastomycosis

Oral ketoconazole is used to treat blastomycosis caused by Blastomyces dermatitidis in selected patients when other effective antifungal therapy is not available or not tolerated. Severe disease (including suspected CNS involvement) generally requires specialist management and alternative systemic therapy.

Chromomycosis

Oral ketoconazole has been used for chromomycosis (chromoblastomycosis) caused by Phialophora spp. Response may vary, and treatment choice should be individualized by a clinician experienced in systemic mycoses.

Coccidioidomycosis

Oral ketoconazole is used for mild to moderate coccidioidomycosis in selected patients when other effective therapies cannot be used. Severe pulmonary disease or disseminated infection requires aggressive antifungal therapy under medical supervision.

Histoplasmosis

Oral ketoconazole is used for histoplasmosis caused by Histoplasma capsulatum in selected patients when other effective therapies are not available or tolerated. The choice of therapy depends on disease severity, immune status, and clinical response.

Paracoccidioidomycosis

Oral ketoconazole is used to treat paracoccidioidomycosis (South American blastomycosis) caused by Paracoccidioides spp., particularly when alternative antifungal therapy is not available or tolerated.

Dosage and Directions

Take ketoconazole tablets exactly as prescribed by your healthcare provider.

The usual initial adult dosage recommended in US prescribing information is 200 mg once daily. For severe infections or if the expected clinical response is not achieved, the dose may be increased to 400 mg once daily based on clinical response and tolerability.

Pediatric use: ketoconazole tablets have not been systematically studied in children; use in pediatric patients is generally avoided unless a specialist determines that the potential benefit outweighs the risks.

Administration

Ketoconazole requires stomach acid for absorption. Medicines that reduce stomach acidity (such as antacids, H2-blockers, and proton pump inhibitors) may reduce absorption. If you take acid-reducing medicines or have low stomach acid, ask your prescriber or pharmacist how to take ketoconazole and how to separate doses.

Important Safety Information

Ketoconazole tablets can cause serious side effects, including severe liver injury (which may be fatal or require liver transplant), adrenal insufficiency, and QT prolongation (serious heart rhythm problems). Your healthcare provider may order blood tests to check liver function before and during treatment.

When to seek medical help

Stop taking ketoconazole tablets and seek medical help right away if you develop symptoms of liver injury (such as loss of appetite, nausea/vomiting, unusual tiredness, stomach pain, dark urine, light-colored stools, yellowing of the skin or eyes, fever, or rash).

Precautions

Tell your healthcare provider if you have liver problems now or in the past, heart rhythm problems, adrenal problems, or if you take multiple medicines (including OTC products and supplements). Avoid alcohol while taking ketoconazole tablets.

Contraindications

Ketoconazole tablets are contraindicated in patients with known hypersensitivity to ketoconazole.

Because ketoconazole can prolong the QT interval and cause serious drug interactions, coadministration with certain medicines is contraindicated. Examples listed in official product information include: dofetilide, quinidine, pimozide, cisapride, methadone, disopyramide, dronedarone, and ranolazine (and in some labeling, lurasidone), due to the risk of life-threatening ventricular dysrhythmias such as torsades de pointes.

Coadministration with certain benzodiazepines such as oral midazolam or triazolam is contraindicated because ketoconazole can markedly increase their concentrations and effects.

Pregnancy and Breastfeeding

Pregnancy: Tell your healthcare provider if you are pregnant or plan to become pregnant. It is not known if ketoconazole tablets will harm your unborn baby.

Breastfeeding: Ketoconazole can pass into breast milk. You and your healthcare provider should decide if you will take ketoconazole tablets or breastfeed. You should not do both.

Possible Side Effects

Side effects may include nausea, abdominal discomfort, diarrhea, headache, dizziness, and abnormal liver function tests. Ketoconazole can interfere with steroid biosynthesis and may cause endocrine-related adverse effects (e.g., gynecomastia, menstrual irregularities, decreased libido, or adrenal suppression), especially at higher doses.

Drug Interactions

Ketoconazole is a strong inhibitor of CYP3A4 and has many clinically significant drug interactions. Some combinations are contraindicated due to the risk of serious heart rhythm problems (QT prolongation), excessive sedation, or other severe adverse effects.

Drug classes that may interact include medicines that affect heart rhythm, certain sedatives, some cholesterol-lowering medicines, immunosuppressants, anticoagulants, and many others. Tell your healthcare provider and pharmacist about all prescription and over-the-counter medicines, vitamins, and herbal supplements you take before starting ketoconazole.

Drugs affecting gastric acidity (antacids, H2-blockers, PPIs, sucralfate) may reduce ketoconazole absorption. Ask a pharmacist about spacing doses if these medicines are necessary.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time.

Overdose

In case of overdose, seek emergency medical help or contact a Poison Control Center. Treatment is supportive.

Storage

Ketoconazole tablets should be protected from moisture and stored in well-closed containers at 59–77°F (15–25°C). Keep out of reach of children.