Ketoconazole (Generic Name)

Other names: Nizoral

About This Drug

High-dose ketoconazole is used to treat prostate cancer. It is given by mouth (orally).

Possible Side Effects

  • Nausea and throwing up (vomiting). These symptoms may happen within a few hours after your treatment. Medicines are available to stop or lessen these side effects.
  • Stomach pain
  • Decreased appetite (decreased hunger)
  • Skin problems. You may develop a rash, dry skin, or itching. The skin on your elbows, legs, underarms, and in other folds of your skin may feel sticky.
  • Changes in your nails. Your fingernails and toe nails may become dry or cracked. They may grow slower than normal
  • Loose bowel movements (diarrhea) that may last for a few days
  • High blood pressure
  • Changes in your liver function.  Your doctor will check your liver function as needed. 
  • Swelling of your legs, ankles, and/or feet
  • Breast swelling, tenderness, and pain
  • Hot flashes
  • Impotence
  • Erectile dysfunction
  • Weakness

Treating Side Effects

  • Take this drug with food to help lessen nausea and throwing up.
  • Ask your doctor or nurse about medicine to help prevent or lessen nausea, throwing up, loose bowel movements, pain, or itching.
  • Drink 6-8 cups of fluids each day unless your doctor has told you to limit your fluid intake due to some other health problem. A cup is 8 ounces of fluid. If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack water in the body from losing too much fluid).
  • If you develop a rash do not put anything on it unless your doctor or nurse says you may. Keep the area around the rash clean and dry. Ask your doctor for medicine if your rash bothers you.

Food and Drug Interactions

  • Do not eat grapefruit or drink grapefruit juice while taking this drug.
  • There are known interactions of ketoconazole with some other medications and products like ranitidine (Zantac®), omeprazole (Prilosec®), and Tums®.  Ask your doctor what over-the-counter medicine you can take for upset stomach, heart burn, or acid reduction.
  • Talk with your doctor about taking St. John’s Wort, garlic, ginseng, and ginkgo. Tell your doctor and pharmacist about all the medicines and dietary supplements (vitamins, minerals, herbs and others) that you are taking at this time. The safety and use of dietary supplements and alternative diets are often not known. Using these might affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.

When to Call the Doctor

Call your doctor or nurse right away if you have any of these symptoms:

  • Nausea that stops you from eating or drinking
  • Throwing up more than 3 times in one day
  • Feeling confused
  • Trouble waking up
  • Yellowing of the skin or eyes
  • Severe headache
  • Signs of liver problems: dark urine, pale stools, severe stomach pain, feeling very tired and weak, unusual itching, or yellowing of the eyes or skin

Call your doctor or nurse as soon as possible if you have any of these symptoms:

  • Nausea, throwing up, or itching that is not relieved by prescribed medicines
  • Lasting loss of appetite or rapid weight loss (more than 5 pounds in 1 week)
  • Loose bowel movements (diarrhea) more than 5 or 6 times a day or diarrhea with weakness
  • Extreme weakness that interferes with normal activities
  • Muscle pain or weakness
  • Swelling of your legs, ankles, or feet 

Reproduction Concerns

  • Pregnancy warning: It is not known if this drug may harm an unborn child.  For this reason, be sure to talk with your doctor if you are pregnant or planning to become pregnant while getting this drug.
  • Breast feeding warning: Women should not breast feed during treatment because this drug could enter the breast milk and badly harm a breast feeding baby.

Revised July 2014

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