Nizoral (Ketoconazole)

Ketoconazole is an azole antifungal that interferes with fungal cell membrane synthesis, making it effective for several dermatologic fungal conditions.

• Tinea corporis: reduces fungal growth on the body, relieving redness and scaling.
• Tinea cruris: clears infection in the groin area, diminishing itching and erythema.
• Seborrheic dermatitis: controls yeast‑related inflammation on the scalp and face, decreasing flaking and irritation.
• Dandruff: diminishes Malassezia overgrowth, reducing scalp scaling and itch.

• Ketoconazole inhibits the fungal enzyme lanosterol 14α-demethylase, a cytochrome P450 isozyme required for conversion of lanosterol to ergosterol. By blocking this step, the drug disrupts ergosterol synthesis, compromising fungal cell membrane integrity and leading to inhibited growth or cell death. The action is selective for fungal cells, providing topical antifungal activity. Topical application allows high local concentrations while minimizing systemic exposure.

Ketoconazole topical preparations may cause local skin reactions and, rarely, systemic adverse events.

Common Side Effects

• Skin irritation: mild redness, itching, or burning at the application site.
• Dryness: localized skin dryness or flaking.
• Pruritus: increased itching sensation.
• Contact dermatitis: allergic skin reaction.

Serious or Rare Side Effects

• Severe allergic reaction: swelling, hives, or difficulty breathing.
• Hepatotoxicity: abnormal liver function tests observed with extensive use.
• Hormonal effects: rare inhibition of steroid synthesis leading to endocrine disturbances.

When using ketoconazole topical products, certain precautions should be observed to ensure safety and effectiveness.

• Application area: limit use to affected skin and avoid mucous membranes.
• Duration: follow prescriber instructions; prolonged use may increase risk of irritation.
• Concurrent skin conditions: avoid use on broken skin or severe eczema without medical advice.
• Pregnancy and lactation: consult healthcare provider before use, as safety data are limited.
• Drug interactions: topical ketoconazole has minimal systemic absorption but may interact with other topical agents; discuss with a pharmacist.
• Store at ambient temperature: keep below 25°C in the original container, protect from moisture and direct sunlight.

Ketoconazole can interact with other medications, primarily through enzyme inhibition, although topical use results in low systemic exposure.

Major Interactions (Avoid)

• Oral azole antifungals: concurrent use may increase systemic ketoconazole levels and toxicity.
• Systemic corticosteroids: may enhance risk of adrenal suppression when combined with extensive ketoconazole exposure.
• Hepatotoxic drugs: co‑administration can raise risk of liver injury.

Moderate Interactions (Monitor Closely)

• Warfarin: ketoconazole may potentiate anticoagulant effect; monitor INR.
• Cytochrome P450 substrates: drugs metabolized by CYP3A4 may have altered levels; monitor clinical response.
• Topical irritants: combined use with other irritating skin products may increase local reactions.