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SPORANOX® 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. If clinical signs or symptoms develop that are consistent with liver disease, treatment should be discontinued and liver function testing performed. The risks and benefits of SPORANOX® use should be reassessed. (See WARNINGS: Hepatic Effects and PRECAUTIONS: Hepatotoxicity and PATIENT INFORMATION.)

Adverse Events Reported in Oropharyngeal or Esophageal Candidiasis Trials

U.S. adverse experience data are derived from 350 immunocompromised patients (332 HIV seropositive/AIDS) treated for oropharyngeal or esophageal candidiasis. Table 2 below lists adverse events reported by at least 2% of patients treated with SPORANOX® Oral Solution in U.S. clinical trials. Data on patients receiving comparator agents in these trials are included for comparison.

Table 2: Summary of Adverse Events Reported by ≥ 2% of SPORANOX® Treated Patients in U.S. Clinical Trials (Total)

Adverse events reported by less than 2% of patients in U.S. clinical trials with SPORANOX® included: adrenal insufficiency, asthenia, back pain, dehydration, dyspepsia, dysphagia, flatulence, gynecomastia, hematuria, hemorrhoids, hot flushes, implantation complication, infection unspecified, injury, insomnia, male breast pain, myalgia, pharyngitis, pruritus, rhinitis, rigors, stomatitis ulcerative, taste perversion, tinnitus, upper respiratory tract infection, vision abnormal, and weight decrease. Edema, hypokalemia and menstrual disorders have been reported in clinical trials with itraconazole capsules.

Adverse Events Reported from Other Clinical Trials

A comparative clinical trial in patients who received intravenous itraconazole followed by SPORANOX® Oral Solution or received Amphotericin B reported the following adverse events in the itraconazole intravenous/SPORANOX® Oral Solution treatment arm which are not listed above in the subsection “Adverse Events Reported in Oropharnyngeal or Esophageal Candidiasis Trials” or listed below as postmarketing reports of adverse drug reactions: serum creatinine increased, blood urea nitrogen increased, renal function abnormal, hypocalcemia, hypomagnesemia, hypophosphatemia, hypotension, tachycardia, tremor, and pulmonary infiltration.

Post-marketing Experience

Adverse drug reactions that have been identified during post-approval use of SPORANOX® (all formulations) are listed in the table below. Because these reactions are reported voluntarily from a population of uncertain size, reliably estimating their frequency or establishing a causal relationship to drug exposure is not always possible.

Postmarketing Reports of Adverse Drug Reactions

There is limited information on the use of SPORANOX® during pregnancy. Cases of congenital abnormalities including skeletal, genitourinary tract, cardiovascular and ophthalmic malformations as well as chromosomal and multiple malformations have been reported during post-marketing experience. A causal relationship with SPORANOX® has not been established. (See CLINICAL PHARMACOLOGY: Special Populations, CONTRAINDICATIONS, WARNINGS, and PRECAUTIONS: DRUG INTERACTIONS for more information.)

Itraconazole and its major metabolite, hydroxyitraconazole, are inhibitors of CYP3A4. Therefore, the following drug interactions may occur (See Table 1 below and the drug class subheadings that follow):

1. SPORANOX® may decrease the elimination of drugs metabolized by CYP3A4, resulting in increased plasma concentrations of these drugs when they are administered with SPORANOX®. These elevated plasma concentrations may increase or prolong both therapeutic and adverse effects of these drugs. Whenever possible, plasma concentrations of these drugs should be monitored, and dosage adjustments made after concomitant SPORANOX®therapy is initiated. When appropriate, clinical monitoring for signs or symptoms of increased or prolonged pharmacologic effects is advised. Upon discontinuation, depending on the dose and duration of treatment, itraconazole plasma concentrations decline gradually (especially in patients with hepatic cirrhosis or in those receiving CYP3A4 inhibitors). This is particularly important when initiating therapy with drugs whose metabolism is affected by itraconazole.
2. Inducers of CYP3A4 may decrease the plasma concentrations of itraconazole. SPORANOX® may not be effective in patients concomitantly taking SPORANOX® and one of these drugs. Therefore, administration of these drugs with SPORANOX® is not recommended.
3. Other inhibitors of CYP3A4 may increase the plasma concentrations of itraconazole. Patients who must take SPORANOX® concomitantly with one of these drugs should be monitored closely for signs or symptoms of increased or prolonged pharmacologic effects of SPORANOX®.

Table 1: Selected Drugs that Are Predicted to Alter the Plasma Concentration of Itraconazole or Have Their Plasma Concentration Altered by SPORANOX®¹

Antiarrhythmics

The class IA antiarrhythmic quinidine and class III antiarrhythmic dofetilide are known to prolong the QT interval. Coadministration of quinidine or dofetilide with SPORANOX® may increase plasma concentrations of quinidine or dofetilide which could result in serious cardiovascular events. Therefore, concomitant administration of SPORANOX® and quinidine or dofetilide is contraindicated. (See BOX WARNING, CONTRAINDICATIONS, and WARNINGS.)

The class IA antiarrhythmic disopyramide has the potential to increase the QT interval at high plasma concentrations. Caution is advised when SPORANOX® and disopyramide are administered concomitantly.

Concomitant administration of digoxin and SPORANOX® has led to increased plasma concentrations of digoxin via inhibition of P-glycoprotein.

Anticoagulants

SPORANOX® enhances the anticoagulant effect of coumarin-like drugs, such as warfarin.

Anticonvulsants

Reduced plasma concentrations of itraconazole were reported when SPORANOX® was administered concomitantly with phenytoin. Carbamazepine, phenobarbital, and phenytoin are all inducers of CYP3A4. Although interactions with carbamazepine and phenobarbital have not been studied, concomitant administration of SPORANOX® and these drugs would be expected to result in decreased plasma concentrations of itraconazole. In addition, in vivo studies have demonstrated an increase in plasma carbamazepine concentrations in subjects concomitantly receiving ketoconazole. Although there are no data regarding the effect of itraconazole on carbamazepine metabolism, because of the similarities between ketoconazole and itraconazole, concomitant administration of SPORANOX® and carbamazepine may inhibit the metabolism of carbamazepine.

Antimycobacterials

Drug interaction studies have demonstrated that plasma concentrations of azole antifungal agents and their metabolites, including itraconazole and hydroxyitraconazole, were significantly decreased when these agents were given concomitantly with rifabutin or rifampin. In vivo data suggest that rifabutin is metabolized in part by CYP3A4. SPORANOX® may inhibit the metabolism of rifabutin. Although no formal study data are available for isoniazid, similar effects should be anticipated. Therefore, the efficacy of SPORANOX® could be substantially reduced if given concomitantly with one of these agents. Coadministration is not recommended.

Antineoplastics

SPORANOX® may inhibit the metabolism of busulfan, docetaxel, and vinca alkaloids.

Antipsychotics

Pimozide is known to prolong the QT interval and is partially metabolized by CYP3A4. Coadministration of pimozide with SPORANOX®could result in serious cardiovascular events. Therefore, concomitant administration of SPORANOX® and pimozide is contraindicated. (See BOX WARNING, CONTRAINDICATIONS, and WARNINGS.)

Benzodiazepines

Concomitant administration of SPORANOX® and alprazolam, diazepam, oral midazolam, or triazolam could lead to increased plasma concentrations of these benzodiazepines. Increased plasma concentrations could potentiate and prolong hypnotic and sedative effects. Concomitant administration of SPORANOX® and oral midazolam or triazolam is contraindicated. (See CONTRAINDICATIONS and WARNINGS.) If midazolam is administered parenterally, special precaution and patient monitoring are required since the sedative effect may be prolonged.

Calcium Channel Blockers

Edema has been reported in patients concomitantly receiving SPORANOX® and dihydropyridine calcium channel blockers. Appropriate dosage adjustment may be necessary.

Calcium channel blockers can have a negative inotropic effect which may be additive to those of itraconazole; itraconazole can inhibit the metabolism of calcium channel blockers such as dihydropyridines (e.g., nifedipine, nisoldipine, and felodipine) and verapamil. Therefore, caution should be used when co-administering itraconazole and calcium channel blockers due to an increased risk of CHF. Concomitant administration of SPORANOX® and nisoldipine results in clinically significant increases in nisoldipine plasma concentrations, which cannot be managed by dosage reduction. Therefore the concomitant administration of SPORANOX® and nisoldipine is contraindicated. A clinical study showed that felodipine exposure was increased by coadministration of itraconazole, resulting in approximately a 6-fold increase in the AUC and an 8-fold increase in the Cmax. The concomitant use of SPORANOX® and felodipine is contraindicated. (See CONTRAINDICATIONS, WARNINGS, ADVERSE REACTIONS: Post-marketing Experience, and CLINICAL PHARMACOLOGY: Special Populations for more information.)

Gastric Acid Suppressors/Neutralizers

Reduced plasma concentrations of itraconazole were reported when SPORANOX® Capsules were administered concomitantly with H2-receptor antagonists. Studies have shown that absorption of itraconazole is impaired when gastric acid production is decreased. Therefore, SPORANOX® should be administered with a cola beverage if the patient has achlorhydria or is taking H2-receptor antagonists or other gastric acid suppressors. Antacids should be administered at least 1 hour before or 2 hours after administration of SPORANOX®Capsules. In a clinical study, when SPORANOX® Capsules were administered with omeprazole (a proton pump inhibitor), the bioavailability of itraconazole was significantly reduced. However, as itraconazole is already dissolved in SPORANOX® Oral Solution, the effect of H2-antagonists is expected to be substantially less than with the capsules. Nevertheless, caution is advised when the two drugs are coadministered.

Gastrointestinal Motility Agents

Coadministration of SPORANOX® with cisapride can elevate plasma cisapride concentrations which could result in serious cardiovascular events. Therefore, concomitant administration of SPORANOX® with cisapride is contraindicated. (See BOX WARNING, CONTRAINDICATIONS, and WARNINGS.)

HMG CoA-Reductase Inhibitors

Human pharmacokinetic data suggest that SPORANOX® inhibits the metabolism of atorvastatin, cerivastatin, lovastatin, and simvastatin, which may increase the risk of skeletal muscle toxicity, including rhabdomyolysis. Concomitant administration of SPORANOX® with HMG CoA-reductase inhibitors, such as lovastatin or simvastatin is contraindicated. (See CONTRAINDICATIONS and WARNINGS.)

Immunosuppressants

Concomitant administration of SPORANOX® and cyclosporine or tacrolimus has led to increased plasma concentrations of these immunosuppressants. Concomitant administration of SPORANOX® and sirolimus could increase plasma concentrations of sirolimus.

Macrolide Antibiotics

Erythromycin and clarithromycin are known inhibitors of CYP3A4 (See Table 1) and may increase plasma concentrations of itraconazole. In a small pharmacokinetic study involving HIV infected patients, clarithromycin was shown to increase plasma concentrations of itraconazole. Similarly, following administration of 1 gram of erythromycin ethyl succinate and 200 mg itraconazole as single doses, the mean Cmax and AUC 0-∞ of itraconazole increased by 44% (90% CI: 119-175%) and 36% (90% CI: 108-171%), respectively.

Oral Hypoglycemic Agents

Severe hypoglycemia has been reported in patients concomitantly receiving azole antifungal agents and oral hypoglycemic agents. Blood glucose concentrations should be carefully monitored when SPORANOX® and oral hypoglycemic agents are coadministered.

Polyenes

Prior treatment with itraconazole, like other azoles, may reduce or inhibit the activity of polyenes such as amphotericin B. However, the clinical significance of this drug effect has not been clearly defined.

Protease Inhibitors

Concomitant administration of SPORANOX® and protease inhibitors metabolized by CYP3A4, such as indinavir, ritonavir, and saquinavir, may increase plasma concentrations of these protease inhibitors. In addition, concomitant administration of SPORANOX® and indinavir and ritonavir (but not saquinavir) may increase plasma concentrations of itraconazole. Caution is advised when SPORANOX® and protease inhibitors must be given concomitantly.

Reverse Transcriptase Inhibitors

Nevirapine is an inducer of CYP3A4. In vivo studies have shown that nevirapine induces the metabolism of ketoconazole, significantly reducing the bioavailability of ketoconazole. Studies involving nevirapine and itraconazole have not been conducted. However, because of the similarities between ketoconazole and itraconazole, concomitant administration of SPORANOX®and nevirapine is not recommended. In a clinical study, when 8 HIV-infected subjects were treated concomitantly with SPORANOX® Capsules 100 mg twice daily and the nucleoside reverse transcriptase inhibitor zidovudine 8 ± 0.4 mg/kg/day, the pharmacokinetics of zidovudine were not affected. Other nucleoside reverse transcriptase inhibitors have not been studied.

Other

• Methadone and levacetylmethadol (levomethadyl) are known to prolong the QT interval and are metabolized by CYP3A4. Co-administration of methadone or levacetylmethadol with SPORANOX® could result in serious cardiovascular events. Therefore, concomitant administration of SPORANOX® and methadone or levacetylmethadol is contraindicated.
• Elevated concentrations of ergot alkaloids can cause ergotism, ie. a risk for vasospasm potentially leading to cerebral ischemia and/or ischemia of the extremities. Concomitant administration of ergot alkaloids such as dihydroergotamine, ergometrine (ergonovine), ergotamine and methylergometrine (methylergonovine) with SPORANOX® is contraindicated.
• Halofantrine has the potential to prolong the QT interval at high plasma concentrations. Caution is advised when SPORANOX® and halofantrine are administered concomitantly.
• In vitro data suggest that alfentanil is metabolized by CYP3A4. Administration with SPORANOX® may increase plasma concentrations of alfentanil.
• Human pharmacokinetic data suggest that concomitant administration of SPORANOX® and buspirone results in significant increases in plasma concentrations of buspirone.
• SPORANOX® may inhibit the metabolism of certain glucocorticosteroids such as budesonide, dexamethasone, fluticasone and methylprednisolone.
• In vitro data suggest that trimetrexate is extensively metabolized by CYP3A4. In vitro animal models have demonstrated that ketoconazole potently inhibits the metabolism of trimetrexate. Although there are no data regarding the effect of itraconazole on trimetrexate metabolism, because of the similarities between ketoconazole and itraconazole, concomitant administration of SPORANOX® and trimetrexate may inhibit the metabolism of trimetrexate.
• Cilostazol and eletriptan are CYP3A4 metabolized drugs that should be used with caution when co-administered with SPORANOX®.
• Fentanyl plasma concentrations could be increased or prolonged by concomitant use of SPORANOX® and may cause potentially fatal respiratory depression.

Last reviewed on RxList: 4/12/2012
This monograph has been modified to include the generic and brand name in many instances.