Ketoconazole Esteve (Ketoconazole)

Ketoconazole is used to treat systemic fungal infections by targeting pathogenic yeasts and molds.

• Blastomycosis: eradicates Blastomyces dermatitidis and resolves pulmonary and disseminated disease.
• Histoplasmosis: eliminates Histoplasma capsulatum, improving symptoms of acute and chronic infection.
• Candidiasis: clears systemic Candida species, preventing organ involvement and bloodstream infection.

• Ketoconazole inhibits the fungal enzyme lanosterol 14α‑demethylase, a cytochrome P450 isoform essential for converting lanosterol to ergosterol. By blocking ergosterol synthesis, the drug disrupts the integrity of the fungal cell membrane, leading to increased permeability and ultimately cell death.

Ketoconazole may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Vomiting: occasional episodes after dosing.
• Abdominal pain: cramping or discomfort in the gastrointestinal tract.
• Headache: transient headache during therapy.
• Rash: mild skin erythema or itching.
• Elevated liver enzymes: mild transaminase increase.

Serious or Rare Side Effects

• Hepatotoxicity: severe liver injury requiring monitoring.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis: life‑threatening skin reactions.
• Adrenal insufficiency: suppression of cortisol synthesis.
• QT interval prolongation: risk of cardiac arrhythmia.
• Severe hypersensitivity: anaphylaxis or angioedema.

Before initiating therapy, clinicians should consider several safety measures.

• Liver function monitoring: assess baseline transaminases and repeat during treatment.
• Drug interaction review: evaluate concomitant medications metabolized by CYP3A4.
• Hypersensitivity avoidance: discontinue if rash or allergic reaction occurs.
• Cardiac risk assessment: avoid in patients with known QT prolongation.
• Pregnancy and lactation: weigh benefits against potential fetal risk; use only if clearly needed.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture and light.

Ketoconazole interacts with several drug classes and may alter their plasma levels.

Major Interactions (Avoid)

• CYP3A4 substrates (e.g., certain statins, midazolam): risk of toxicity due to inhibited metabolism.
• Oral contraceptives: reduced efficacy, leading to possible unintended pregnancy.
• Anticoagulants (warfarin): increased INR and bleeding risk.

Moderate Interactions (Monitor Closely)

• QT‑prolonging agents (e.g., quinidine, sotalol): additive effect on cardiac conduction.
• Hepatotoxic drugs (e.g., isoniazid, acetaminophen): heightened liver injury potential.
• Immunosuppressants (e.g., cyclosporine): possible increased levels requiring dose adjustment.