Ketoconazole – Broad-Spectrum Antifungal Agent

Discover everything about Ketoconazole: an effective antifungal medication. Learn about its uses, mechanism of action, dosage, side effects, contraindications, drug interactions, brand names, and pricing in detail.

Table of Contents:

1. Introduction  

2. Mechanism of Action  

3. Pharmacokinetics and Pharmacodynamics  

4. Indications  

5. Drug of Choice  

6. Contraindications  

7. Side Effects  

8. Drug Interactions  

9. Dosage  

10. Brand Names and Price  

11. Conclusion

1. Introduction:

*Ketoconazole* is a synthetic *imidazole antifungal agent* used in the treatment of various fungal infections. It is available in oral, topical, and shampoo formulations. Though its systemic use has declined due to hepatotoxicity concerns, it remains widely used topically.

2. Mechanism of Action:

Ketoconazole inhibits *fungal cytochrome P450 enzyme 14α-demethylase*, blocking the conversion of lanosterol to ergosterol — an essential component of the fungal cell membrane. This disruption impairs membrane integrity, leading to fungal cell death.

3. Pharmacokinetics and Pharmacodynamics:

- *Absorption:* Requires acidic pH for proper absorption  

- *Bioavailability:* ~37% orally  

- *Protein Binding:* >99%  

- *Metabolism:* Hepatic (CYP3A4)  

- *Half-life:* ~8 hours  

- *Excretion:* Mainly via bile and feces

4. Indications:

- *Topical treatment of tinea infections* (corporis, cruris, pedis)  

- *Seborrheic dermatitis* (as shampoo)  

- *Pityriasis versicolor*  

- *Candidiasis (cutaneous)*  

- *Systemic fungal infections* (only if no alternatives are available)

5. Drug of Choice:

- Topical *seborrheic dermatitis* and *pityriasis versicolor*  

- Often used in *shampoo form* for fungal scalp conditions

6. Contraindications:

- Hypersensitivity to ketoconazole  

- Hepatic impairment (oral use)  

- Co-administration with drugs that prolong QT interval or are CYP3A4 substrates

7. Side Effects:

- *Oral:* Hepatotoxicity, nausea, vomiting, abdominal pain, gynecomastia  

- *Topical:* Skin irritation, itching, burning sensation

- *Endocrine:* Inhibition of adrenal steroidogenesis (with high doses)

8. Drug Interactions:

- *CYP3A4 inhibitors or inducers* affect levels  

- *Statins, warfarin, rifampin, phenytoin:* Use with caution  

- *Alcohol:* May increase hepatotoxic risk  

- Avoid combining with QT-prolonging agents

9. Dosage:

- *Topical (cream):* Apply once or twice daily for 2–4 weeks  

- *Shampoo:* Twice weekly for 2–4 weeks (scalp conditions)  

- *Oral (if essential):* 200–400 mg daily (under close supervision)  

- *Note:* Oral use is restricted due to liver toxicity risk

10. Brand Names and Price:

Brand Names:

  - Nizoral®️  

  - Ketoderm®️  

  - Fungoral®️  

  - Xolegel®️  

Price Range:

  - Cream (15g): 2–8  

  - Shampoo (100ml): 5–15  

  - Oral tabs: Varies; often restricted

11. Conclusion:

Ketoconazole remains a useful antifungal agent, particularly in its *topical forms*, for treating skin and scalp infections. Due to the risk of hepatotoxicity, its *oral use is now limited* and monitored strictly. When used appropriately, Ketoconazole is a valuable part of antifungal therapy, especially in dermatological conditions.