Ketoconazole is a synthetic imidazole antifungal drug used primarily to treat fungal infections. Ketoconazole is sold commercially as a tablet for oral administration, and in a variety of formulations for topical administration, such as creams (used to treat tinea; cutaneous candidiasis, including candidal paronychia; and pityriasis versicolor) and shampoos (used primarily to treat dandruff seborrhoeic dermatitis of the scalp).

Molecular Structure

Class of Drug

Antibiotic, penicillin family, aminopenicillin.

Mechanism of Action

Inhibits synthesis of steroids in fungal cell membranes, resulting in leakage of essential cellular components

Susceptible organisms in vivo: Candida sp, Cryptococcus, Coccidioides, Histoplasma, Blastomyces.

Indications / Dosage / Route

Routes of Administration: Oral only.

Condition: Systemic fungal infections

Dose: Adults: 200 mg once daily. Increase to 400 mg once daily if needed.

         Children >2 years 3.3-6.6 mg/kg once daily

Adjustment of Dosage

Kidney disease: None

Liver disease: None.

Elderly: None

Pediatric: Safety and efficacy in children <2 years have not been established.

Food and Drug Interactions

Food: Should be taken with food, especially citrus juices.

Pregnancy: Category C.

Lactation: Probably present in breast milk. Avoid breastfeeding.

Contraindications: Hypersensitivity to ketoconazole or other azole antifungals, concomitant astemizole, triazolam.

Warnings / Precautions

> Treatment of candidiasis requires 1-2 weeks; for other systemic mycoses, 6 months.

> Do not administer along with astemizole or other azoles.

Clinically Important Drug Interactions

> Ketoconazole increases effects/toxicity of hepatotoxic drugs, cisapride, oral anticoagulants, astemizole, cyclosporine, astemizole, corticosteroids, midazolam, triazolam.

> Ketoconazole decreases effects/toxicity of theophylline.

> The following drugs decrease effects/toxicity of ketoconazole: antacids (containing calcium, aluminum), anticholinergics, rifampin, isoniazid.

Adverse Reactions

> Common: Nausea, vomiting, diarrhea, abdominal pain

> Serious: hepatotoxicity.

Parameters to Monitor

> Signs and symptoms of liver toxicity.

Advice to Patient

> Take antacids, if needed, 2 hours after this drug. The same is true for other drugs that decrease gastric activity, eg, H2 blockers.

> Report symptoms of possible liver dysfunction: jaundice, anorexia, dark urine, pale stools, nausea, vomiting.

> Avoid driving and other activities requiring mental alertness or that are potentially dangerous until response to drug is known.

> Avoid alcohol.

> To minimize possible photosensitivity reaction, apply adequate sunscreen and use proper covering when exposed to strong sunlight.

Further Useful Info

> Ketoconazole is effective in non-CNS infections caused by Candida, blastomycosis, histoplasmosis, and coccidiomycosis.

> Problems with oral absorption occur, especially in patients with AIDS, neutropenic patients, or patients on antacids or other acid-blocking agents.

> This drug should not be used in cryptoccal infections. Fluconazole should be substituted.

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