Triazole Antifungal — Dermatophytes / Aspergillus / Endemic Mycoses Pregnancy: Contraindicated in 1st trimester — teratogenic in animal studies; use fluconazole (short course) or amphotericin as alternative; avoid throughout if possible

Itraconazole

Brand names: Sporanox

Adult dose

Dose: Oral capsules (with food): 100–200 mg once or twice daily; Oral solution (on empty stomach): 200 mg once daily; IV loading: 200 mg twice daily × 2 days, then 200 mg once daily

Route: Oral (capsule or solution) or IV

Frequency: Once or twice daily (formulation-dependent)

Max: 400 mg/day

IMPORTANT formulation difference: capsules require food and acid for absorption; oral solution (cyclodextrin vehicle) taken on empty stomach — 30% better bioavailability than capsules. Check plasma levels (trough) — significant intra-patient variability. Used for: dermatophytes (onychomycosis), aspergillosis (alternative), histoplasmosis, blastomycosis, sporotrichosis.

Paediatric dose

Dose: 5 mg/kg mg/kg

Route: Oral solution

Frequency: Once daily

Max: 200 mg/day

BNFc: oral solution preferred in children — better bioavailability; capsules not recommended under 12 years

Dose adjustments

Renal

IV formulation: avoid if CrCl <30 mL/min (cyclodextrin vehicle accumulates); oral — no dose adjustment needed

Hepatic

Use with caution — hepatically metabolised; monitor LFTs; avoid if decompensated liver disease

Paediatric weight-based calculator

Patient weight (kg)

BNFc: oral solution preferred in children — better bioavailability; capsules not recommended under 12 years

Clinical pearls

Capsules vs solution: always check which formulation — oral solution on empty stomach is preferred for reliable absorption; capsule absorption requires gastric acid and food (PPIs reduce absorption significantly)
Trough level monitoring essential: target trough 0.5–1 mg/L (prophylaxis) or >1 mg/L (treatment) — significant variability
Negative inotropic effect: avoid in patients with cardiac disease or heart failure — itraconazole can precipitate HF decompensation; MHRA warning
Aspergillosis: voriconazole is preferred first-line; itraconazole is alternative if voriconazole not tolerated or for step-down oral therapy

Contraindications

Concurrent terfenadine, astemizole, cisapride, quinidine, pimozide (QT prolongation/torsades risk)
Concurrent simvastatin/lovastatin (rhabdomyolysis)
Pregnancy (1st trimester — teratogenic)
Ventricular dysfunction/heart failure (negative inotrope)
Concurrent rifampicin (reduces itraconazole to sub-therapeutic)

Side effects

Nausea and GI disturbance
Hepatotoxicity (elevated LFTs — check monthly)
Peripheral oedema (negative inotropic effect)
Cardiac failure (especially in pre-existing cardiac disease)
QTc prolongation
Peripheral neuropathy (prolonged use)
Hypokalaemia

Interactions

Strong CYP3A4 inhibitor — numerous interactions
Rifampicin — reduces itraconazole levels to zero (contraindicated)
Statins (simvastatin/lovastatin) — rhabdomyolysis
Calcium channel blockers — increased levels (oedema, heart failure)
Warfarin — enhanced INR
Immunosuppressants (ciclosporin, tacrolimus, sirolimus) — increased levels

Monitoring

Itraconazole trough levels (2 weeks after initiation or dose change)
LFTs monthly
ECG (QTc)
Cardiac function (heart failure symptoms)
Potassium

Reference: BNFc; BNF 90; ESCMID/ECMM Aspergillosis Guidelines; MHRA Itraconazole Cardiac Warning; NICE NG133; PHE Fungal Infection Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Pathways