Adults

For oropharyngeal candidiasis: 100 mg (10 mL) once daily for 1 to 2 weeks. For esophageal candidiasis: 100 mg (10 mL) once daily for 2 weeks. For systemic mycoses, dosage varies significantly based on infection type and severity (e.g., 200 mg once or twice daily).

Elderly

Use with caution; dose adjustment may be necessary based on renal or hepatic function and potential for drug interactions. Close monitoring is recommended.

Renal_impairment

Use with caution. Itraconazole is primarily metabolized by the liver; however, metabolites are excreted renally. Dose adjustment may be needed for severe renal impairment. Monitor plasma concentrations if available.

Onset

Therapeutic effects may be observed within days to weeks, depending on the type and severity of infection.

Excretion

Approximately 35% of the dose is excreted in the urine as inactive metabolites and less than 0.03% as unchanged drug. About 54% of the dose is excreted in the feces as inactive metabolites.

Half life

The plasma elimination half-life of itraconazole is approximately 20-30 hours, while its active metabolite, hydroxyitraconazole, has a half-life of about 30-40 hours.

Absorption

Oral solution is better absorbed on an empty stomach, leading to higher and more consistent plasma concentrations compared to capsules taken with food. Peak plasma concentrations are reached within 2-5 hours.

Metabolism

Extensively metabolized in the liver, primarily by the cytochrome P450 3A4 (CYP3A4) isoenzyme, to a large number of metabolites, including the active metabolite hydroxyitraconazole.

Statins (e.g., Simvastatin, Lovastatin)

Itraconazole can increase plasma concentrations of HMG-CoA reductase inhibitors, increasing the risk of myopathy, including rhabdomyolysis. Concomitant use is contraindicated.

CYP3A4 Inhibitors (e.g., Clarithromycin, Ritonavir)

May increase itraconazole plasma concentrations, potentially enhancing adverse effects. Dose adjustment or monitoring may be necessary.

Calcium Channel Blockers (e.g., Amlodipine, Felodipine)

Itraconazole may increase plasma concentrations of calcium channel blockers, potentially leading to increased adverse effects (e.g., edema). Close monitoring and dose adjustment may be required.

CYP3A4 Inducers (e.g., Rifampicin, Phenytoin, Carbamazepine)

May significantly decrease itraconazole plasma concentrations, leading to reduced efficacy. Avoid co-administration.

Drugs that Prolong QT Interval (e.g., Quinidine, Cisapride, Dofetilide)

Itraconazole can increase plasma concentrations of these drugs, leading to life-threatening cardiac arrhythmias (e.g., Torsades de Pointes). Concomitant use is contraindicated.