Adults

Onychomycosis: 200 mg once daily for 3 months, or pulse therapy: 200 mg twice daily for 1 week, then 3 weeks drug-free, repeat for 2-3 cycles. Vulvovaginal Candidiasis: 200 mg twice daily for 1 day or 200 mg once daily for 3 days. Oral Candidiasis: 100-200 mg once daily for 2-4 weeks. Systemic fungal infections: 100-400 mg daily, duration depends on the infection.

Elderly

Use with caution; dosage adjustment may be necessary in some cases due to age-related decrease in hepatic or renal function.

Renal_impairment

Use with caution. Itraconazole and its metabolites are mainly excreted in the feces. However, experience in renally impaired patients is limited, and dosage adjustment might be needed. Closely monitor patients with severe renal impairment.

Onset

Antifungal effects typically manifest within several days to weeks, depending on the infection.

Excretion

Approximately 35-54% of the dose is excreted in feces, and 3-18% in urine, mainly as inactive metabolites. Less than 0.03% of the dose is excreted unchanged in urine.

Half life

Initial half-life is approximately 20-30 hours after a single dose, increasing to 30-40 hours with repeated dosing due to saturation of metabolism.

Absorption

Oral bioavailability of capsules is approximately 55% when taken with a full meal. Absorption is increased in the presence of food and gastric acid. Peak plasma concentrations are achieved 2-5 hours post-dose.

Metabolism

Extensively metabolized in the liver, primarily by the cytochrome P450 3A4 (CYP3A4) enzyme system, to several metabolites, including the main active metabolite, hydroxyitraconazole.

Pimozide, Quinidine, Cisapride

Increased plasma concentration, leading to QT prolongation and serious cardiac arrhythmias. Concomitant use is contraindicated.

Oral Anticoagulants (e.g., Warfarin)

Increased anticoagulant effect, leading to increased risk of bleeding. Close monitoring of INR is required.

Rifampicin, Phenytoin, Carbamazepine

These are potent CYP3A4 inducers, significantly reducing itraconazole plasma levels and efficacy. Concomitant use should be avoided.

Statins (e.g., Simvastatin, Lovastatin)

Increased plasma concentration of statins, leading to increased risk of rhabdomyolysis. Concomitant use is contraindicated.

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

Increased plasma concentration of calcium channel blockers, leading to increased hypotensive effects and peripheral edema. Dosage reduction may be necessary.