Adults

Typical dosage ranges from 100 mg once daily to 200 mg twice daily, depending on the infection. For Onychomycosis, pulsed dosing regimens are common (e.g., 200 mg twice daily for 7 days per month).

Elderly

No specific dosage adjustment based on age alone is generally required, but caution is advised, and dose adjustments may be needed for renal or hepatic impairment.

Renal_impairment

Use with caution in patients with renal impairment. Systemic exposure to Itraconazole may be reduced in severe renal impairment; however, an increase in exposure to some metabolites has been observed. Dosage adjustment may be considered.

Onset

Therapeutic effects may take several days to weeks, depending on the type and severity of fungal infection.

Excretion

Excreted primarily in feces (3-18% unchanged drug, 34-54% as metabolites) and to a lesser extent in urine (0.03% unchanged drug, 65% as metabolites).

Half life

Terminal elimination half-life is approximately 20-30 hours after single dose, increasing to 30-40 hours with chronic dosing.

Absorption

Oral absorption is variable and significantly increased when taken with food or an acidic beverage. Peak plasma concentrations are reached within 3-5 hours.

Metabolism

Extensively metabolized in the liver mainly by cytochrome P450 3A4 (CYP3A4) to several metabolites, including the active metabolite hydroxyitraconazole, which has comparable antifungal activity.

Proton Pump Inhibitors/H2 Blockers/Antacids

Reduced absorption of Itraconazole due to increased gastric pH. Administer Itraconazole with an acidic beverage or consider alternative antifungal therapy.

CYP3A4 Substrates (e.g., statins, benzodiazepines, CCBs)

Increased plasma levels of these drugs, leading to increased risk of toxicity. Dose adjustments or alternatives may be needed.

CYP3A4 Inducers (e.g., rifampicin, phenytoin, carbamazepine)

Decreased plasma levels of Itraconazole, leading to reduced efficacy. Avoid co-administration if possible.