Overview
DESCRIPTION Itraconazole capsule, USP is the generic name for itraconazole, USP an azole antifungal agent. Itraconazole, USP is a 1:1:1:1 racemic mixture of four diastereomers (two enantiomeric pairs), each possessing three chiral centers. It may be represented by the following structural formula and nomenclature: ±)-1-[( R *)- sec -butyl]-4-[ p -[4-[ p -[[(2 R *,4 S...
Mechanism of Action
CLINICAL PHARMACOLOGY Pharmacokinetics and Metabolism: General Pharmacokinetic Characteristics Peak plasma concentrations of itraconazole are reached within 2 to 5 hours following oral administration. As a consequence of non-linear pharmacokinetics, itraconazole accumulates in plasma during multiple dosing. Steady-state concentrations are generally reached within about 15 days, with C max values of 0.5 μg/mL, 1.1 μg/mL and 2 μg/mL after oral administration of 100 mg once daily, 200 mg once daily and 200 mg b.i.d., respectively. The terminal half-life of itraconazole generally ranges from 16 to 28 hours after single dose and increases to 34 to 42 hours with repeated dosing.
Indications
- INDICATIONS AND USAGE Itraconazole capsules are indicated for the treatment of the following fungal infections in immunocompromised and non-immunocompromised patients: 1. Blastomycosis, pulmonary and extrapulmonary 2. Histoplasmosis, including chronic cavitary pulmonary disease and disseminated, non- meningeal histoplasmosis, and 3. Aspergillosis, pulmonary and extrapulmonary, in patients who are intolerant of or who are refractory to amphotericin B therapy.
Common Doses
- 200 mg
- 400 mg
- 600 mg
Dosage
DOSAGE AND ADMINISTRATION Itraconazole capsules should be taken with a full meal to ensure maximal absorption. Itraconazole capsules must be swallowed whole. Itraconazole capsule is a different preparation than itraconazole Oral Solution and should not be used interchangeably. Treatment of Blastomycosis and Histoplasmosis: The recommended dose is 200 mg once daily (2 capsules). If there is no obvious improvement, or there is evidence of progressive fungal disease, the dose should be increased in 100-mg increments to a maximum of 400 mg daily.
Black Box Warning
BOXED WARNING Congestive Heart Failure, Cardiac Effects and Drug Interactions Congestive Heart Failure and Cardiac Effects: • Itraconazole capsules should not be administered for the treatment of onychomycosis in patients with evidence of ventricular dysfunction such as congestive heart failure (CHF) or a history of CHF. If signs or symptoms of congestive heart failure occur during administration of itraconazole capsules, discontinue administration. • When itraconazole was administered intravenously to dogs and healthy human volunteers, negative inotropic effects were seen.
Contraindications
- CONTRAINDICATIONS Congestive Heart Failure: Itraconazole capsules should not be administered for the treatment of onychomycosis in patients with evidence of ventricular dysfunction such as congestive heart failure (CHF) or a history of CHF. (See BOXED WARNINGS, WARNINGS, PRECAUTIONS: Drug Interactions-Calcium Channel Blockers, ADVERSE REACTIONS: Postmarketing Experience, and CLINICAL PHARMACOLOGY: Special Populations.) Drug Interactions: Coadministration of a number of CYP3A4 substrates are contraindicated with itraconazole.
Side Effects
- ADVERSE REACTIONS Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Itraconazole has been associated with rare cases of serious hepatotoxicity, including liver failure and death. Some of these cases had neither pre-existing liver disease nor a serious underlying medical condition.
Interactions
- Drug Interactions: Effect of Itraconazole on Other Drugs Itraconazole and its major metabolite, hydroxy-itraconazole, are potent CYP3A4 inhibitors. Itraconazole is an inhibitor of the drug transporters P-glycoprotein and breast cancer resistance protein (BCRP). Consequently, itraconazole has the potential to interact with many concomitant drugs resulting in either increased or sometimes decreased concentrations of the concomitant drugs.