What is itraconazole, and how does it work (mechanism of action)?

Itraconazole is an anti-fungal drug in the same class of drugs as fluconazole (Diflucan), ketoconazole (Nizoral), and miconazole (Micatin, Monistat). It prevents growth of several types of fungi by preventing the fungi from producing the membranes that surround the fungal cells. The FDA approved itraconazole in September 1992.

What brand names are available for itraconazole?

Sporanox, Onmel, Sporanox Pulsepak

Is itraconazole available as a generic drug?

GENERIC AVAILABLE: Yes

Do I need a prescription for itraconazole?

Yes

What are the side effects of itraconazole?

The most common side effects of itraconazole are:

• nausea,
• vomiting,
• diarrhea,
• rash,
• edema,
• fatigue,
• dizziness.

Other important side effects include:

• High blood pressure (hypertension) and
• increased blood triglycerides.

Less common but more serious side effects include hepatitis and congestive heart failure.

It is important to report any signs or symptoms that may suggest liver dysfunction so that the appropriate laboratory testing can be done. These signs include:

• unusual fatigue,
• poor appetite,
• nausea and/or vomiting,
• yellowing of the eyes (jaundice),
• dark urine or
• pale stool.

Itraconazole should not be used for treatment of onychomycosis in patients with a history of heart failure. It should be discontinued if signs and symptoms of heart failure occur. Symptoms of heart failure include fatigue, edema (fluid retention), shortness of breath, nausea, abdominal pain, and inability to sleep unless sitting upright. Use of calcium channel blockers may increase the risk of heart failure associated with itraconazole (see drug interactions).

What is the dosage for itraconazole?

The usual recommended dose is 200-400 mg daily as a single dose or two divided doses. Capsules should be taken with a full meal because food improves absorption. The capsule and liquid are not interchangeable, and only the liquid form is used for treating oral candidiasis.

Which drugs or supplements interact with itraconazole?

Itraconazole reduces the liver metabolism (breakdown) of some drugs, resulting in increased blood levels and side effects from the affected drugs. Life-threatening adverse effects occurred when itraconazole was combined with cisapride (no longer available in the U.S.), pimozide (Orap), quinidine (Quinaglute, Quinidex), dofetilide (Tikosyn), or levomethadyl (Orlaam). Therefore, itraconazole should not be combined with these drugs.

HMG CoA-reductase inhibitors or "statins" such as simvastatin (Zocor) or lovastatin (Mevacor) should also not be combined with itraconazole due to the risk of serious adverse effects.

 Other drugs whose blood levels are increased by itraconazole include warfarin (Coumadin), tolbutamide, glyburide (Micronase, Diabeta, Glynase), glipizide (Glucotrol), protease inhibitors (for example, indinavir [Crixivan], ritonavir [Norvir], saquinavir [Invirase, Fortovase]), midazolam (Versed), triazolam (Halcion) and several others.

Itraconazole increases blood levels of certain calcium channel blockers, for example, nisoldipine (Sular) and verapamil (Calan). Such combinations increase the occurrence of congestive heart failure due to itraconazole. Itraconazole increases blood levels of tacrolimus, sirolimus, and cyclosporine. It may also increase blood levels of fentanyl or prolong elimination of fentanyl, potentially leading to fatal respiratory depression. Clarithromycin (Biaxin), erythromycin, indinavir (Crixivan) or ritonavir (Norvir) increase blood levels of itraconazole by reducing its elimination from the liver, resulting in increased side effects of itraconazole.

Carbamazepine (Tegretol), phenobarbital, phenytoin (Dilantin), rifampin (Rifadin), rifabutin (Mycobutin) and isoniazid reduce the blood concentration of oral itraconazole, probably by increasing the elimination of itraconazole by the liver. This may reduce the effectiveness of itraconazole. Itraconazole tablets require acid from the stomach to dissolve. Therefore, itraconazole should be administered at least two hours before taking antacids or other acid reducing medications such as cimetidine (Tagamet), ranitidine (Zantac) or omeprazole (Prilosec).

Is itraconazole safe to take if I'm pregnant or breastfeeding?

Itraconazole has not been adequately studied in pregnant women. Cases of congenital abnormalities have been reported. Itraconazole should not be used to treat nail fungal infections (onychomycosis) in pregnant patients. Women of child bearing age undergoing treatment for fungal infections of the nails must use adequate contraception measures while receiving itraconazole and for two months after treatment.

Itraconazole is excreted in human milk. Therefore, it should not be administered to nursing women or, alternatively, breastfeeding should be discontinued.

What else should I know about itraconazole?

What preparations of itraconazole are available?

Capsules: 100 mg; Oral Solution: 10 mg/ml; Injection: 10 mg/ml

How should I keep itraconazole stored?

Capsules should be stored at room temperature, 15 C - 25 C (59 F - 77 F) and protected from light and moisture. Oral and injectable solutions should be stored below 25 C (77 F) but not frozen.