Along with its needed effects, ketoconazole may cause some unwanted or undesirable effects. The severity and duration of these effects are dependant on many factors including duration of therapy, dose, and individual response. Possible unwanted effects include:

• nausea
• vomiting
• stomach pain

Uncommon:

• diarrhea
• headache
• dizziness
• drowsiness
• itching
• skin reactions
• liver problems

Ketoconazole is an antifungal agent. It works by interfering with the production of the main building block of the fungal cell membrane. This allows the contents of the cell to leak out, resulting in fungal cell death.

Ketoconazole should be taken exactly as prescribed. Continue taking the medication until it is finished or it will prevent complete elimination of the fungi (e.g. yeast), causing the infection to return.
Ketoconazole has caused liver disease in some patients. Notify your doctor if you experience any of the following signs or symptoms: unusual fatigue, appetite loss, nausea, vomiting, yellowing of the skin or eyes (jaundice), dark urine or pale stools. Depending on the length of ketoconazole therapy, lab tests may be required to monitor how well your body is handling the ketoconazole. These tests will include liver function tests.
Treatment with ketoconazole can last as little as 1 week when treating thrush or in excess of 6 months when treating certain internal infections.

Antacids interfere with the dissolving of ketoconazole in the stomach, making it far less effective. Therefore, antacids should not be taken within 2 hours of the ketoconazole dose.

Drug Interactions: It is important to tell your doctor and pharmacist about any prescription or over-the-counter medications you are taking to help avoid any serious drug interactions. The dose of one or both medications may need to be altered or a new drug may be prescribed. In some cases, one of the drugs may have to be discontinued. The following drugs and drug classes have been known to interact with ketoconazole:

• antacids
• acid blockers (e.g. cimetidine)
• isoniazid
• rifampin
• warfarin (e.g. Coumadin®)
• corticosteroids (e.g. methylprednisolone)
• cyclosporine (e.g. Neoral®)
• alcohol
• phenytoin (e.g. Dilantin®)
• triazolam (e.g. Halcion®)

Use is not recommended in the following situations:

• allergy to ketoconazole or any component of the preparation
• liver disease

Use in pregnancy: If you suspect that you may be pregnant, contact your doctor or pharmacist.
Use while breastfeeding: Ketoconazole does pass into the breast-milk but is generally considered compatible with breastfeeding. Consult your doctor or pharmacist before use.