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Systemic Antifungal — Onychomycosis / Tinea Pregnancy: Must not be used during pregnancy except in life-threatening cases where the potential benefit to the mother outweighs the potential harm to the foetus; in animal studies itraconazole has shown reproduction toxicity and crosses the placenta in a rat model. Epidemiological data on first-trimester exposure (mostly short-term treatment for vulvovaginal candidosis) did not show an increased risk of malformations compared with controls. Women of childbearing potential should use contraceptive precautions, continued until the menstrual period following the end of therapy. Breast-feeding: a very small amount of itraconazole is excreted in human milk and the oral solution must not be used during lactation.

Itraconazole

Brand names: Sporanox, Itrimul

Itraconazole is a triazole antifungal used for dermatophyte (e.g. nail), candidal and some systemic fungal infections.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Onychomycosis of the toenails (with or without fingernail involvement): 200 mg (2 capsules) once daily for 12 consecutive weeks. Onychomycosis of the fingernails only: pulse therapy — 200 mg (2 capsules) twice daily (400 mg/day) for 1 week, given as 2 treatment pulses separated by a 3-week period without itraconazole.
Route: Oral (capsules). Itraconazole capsules must be swallowed whole and taken with a full meal to ensure maximal absorption.
Frequency: Toenails — once daily for 12 consecutive weeks. Fingernails — twice daily for 1 week per pulse, 2 pulses separated by 3 itraconazole-free weeks.
SOURCE CAVEAT — this dose is from US prescribing information (ITRACONAZOLE capsules, Alembic Pharmaceuticals Inc., label date 2025-03-10) and must be verified against the UK capsule SPC. The eMC record retrieved in this bundle is a DIFFERENT product and a different indication: 'Itraconazole 10mg/ml Sugar Free Oral Solution' (https://www.medicines.org.uk/emc/product/10049/smpc), licensed for oral and/or oesophageal candidosis and for prophylaxis of fungal infections in neutropenic patients — not for skin or nail infection. Both labels state that itraconazole capsules and itraconazole oral solution are NOT interchangeable ('Only the oral solution has been demonstrated effective for oral and/or esophageal candidiasis'). Note the opposite food rules: capsules with a full meal; oral solution without food, refraining from eating for at least 1 hour after intake. OTHER DERMATOLOGICAL INDICATIONS (e.g. tinea corporis/cruris/pedis, pityriasis versicolor) are NOT covered by either label in this bundle — clinician to source the UK capsule SPC before publishing those regimens. CRITICAL SAFETY FOR THIS PAGE: itraconazole capsules must NOT be given for onychomycosis in patients with evidence of ventricular dysfunction such as congestive heart failure or a history of CHF; and itraconazole must not be used during pregnancy for non-life-threatening indications — women of childbearing potential should use contraceptive precautions, continued until the menstrual period following the end of therapy. FOR REFERENCE, the eMC ORAL SOLUTION regimens (different indication — do not apply to skin/nail disease): oral and/or oesophageal candidosis 200 mg (20 mL) per day in two intakes or alternatively in one intake for 1 week, continued for another week if there is no response; fluconazole-resistant oral and/or oesophageal candidosis 100 to 200 mg (10-20 mL) twice daily for 2 weeks, continued for another 2 weeks if there is no response, and the 400 mg (40 mL) daily dose should not be used for longer than 14 days if there are no signs of improvement; prophylaxis of fungal infections 5 mg/kg (0.5 mL/kg) per day in two intakes. For the swished oral candidosis dose the liquid should be swished around the oral cavity for approximately 20 seconds and swallowed, with no rinsing afterwards. US capsule label, other (non-derm) indications: blastomycosis and histoplasmosis 200 mg once daily, increased in 100 mg increments to a maximum of 400 mg daily if there is no obvious improvement (doses above 200 mg/day in two divided doses); aspergillosis 200 to 400 mg daily; in life-threatening situations a loading dose of 200 mg three times daily (600 mg/day) for the first 3 days is recommended. PAEDIATRIC: the eMC oral solution SPC states safety and efficacy in children have not been established and NO RECOMMENDATION ON A POSOLOGY CAN BE MADE, and use in paediatric patients is not recommended unless the potential benefit outweighs the potential risks; the US label states efficacy and safety have not been established in paediatric patients and that long-term effects on bone growth in children are unknown. Hence paedDose is null — verify any paediatric use against a children's formulary. ELDERLY: use only if the potential benefit outweighs the potential risks, reflecting the greater frequency of decreased hepatic, renal or cardiac function. HEPATIC IMPAIRMENT: limited data — exercise caution.

Dose adjustments

Renal

Limited data are available on the use of oral itraconazole in patients with renal impairment. Exposure may be lower in some patients with renal insufficiency, with wide inter-subject variation. Exercise caution; adjusting the dose or switching to an alternative antifungal may be considered based on an evaluation of clinical effectiveness (eMC §4.2).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION Itraconazole capsules should be taken with a full meal to ensure maximal absorption. Itraconazole capsules must be swallowed whole. Itraconazole capsule is a different preparation than itraconazole Oral Solution and should not be used interchangeably. Treatment of Blastomycosis and Histoplasmosis: The recommended dose is 200 mg once daily (2 capsules). If there is no obvious improvement, or there is evidence of progressive fungal disease, the dose should be increased in 100-mg increments to a maximum of 400 mg daily. Doses above 200 mg/day should be given in two divided doses. Treatment of Aspergillosis: A daily dose of 200 to 400 mg is recommended. Treatment in …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-03-10. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

  • Known hypersensitivity to itraconazole or to any of the excipients
  • Evidence of ventricular dysfunction such as congestive heart failure (CHF) or a history of CHF — except for the treatment of life-threatening or other serious infections; capsules must NOT be given for onychomycosis in these patients (US label, BOXED WARNING territory)
  • Must not be used during pregnancy for non-life-threatening indications
  • Co-administration of a number of CYP3A4 substrates, including ergot alkaloids (dihydroergotamine, ergometrine, ergotamine, methylergometrine), isavuconazole, halofantrine, astemizole, mizolastine, terfenadine, irinotecan, venetoclax (during initiation/titration in CLL), dabigatran, ticagrelor, ombitasvir/paritaprevir/ritonavir, aliskiren, eplerenone, quinidine, bepridil, finerenone, ranolazine, disopyramide, ivabradine, sildenafil (pulmonary hypertension), dofetilide, lercanidipine, dronedarone, nisoldipine, cisapride, domperidone, naloxegol, voclosporin, lovastatin, lomitapide, simvastatin, lurasidone, pimozide, sertindole, oral midazolam, quetiapine, triazolam, avanafil, darifenacin, dapoxetine
  • Conditional contraindications: solifenacin (severe renal or moderate-to-severe hepatic impairment), fesoterodine (moderate or severe renal or hepatic impairment), vardenafil (age over 75 years), colchicine (renal or hepatic impairment), eliglustat (CYP2D6 poor or intermediate metabolisers, or extensive metabolisers taking a strong or moderate CYP2D6 inhibitor)

Side effects

  • Dizziness, headache and dysgeusia (common)
  • Abdominal pain, diarrhoea, vomiting, nausea and dyspepsia (common); constipation (uncommon); pancreatitis (not known)
  • Rash (common); urticaria and pruritus (uncommon); serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson syndrome, acute generalised exanthematous pustulosis, erythema multiforme, exfoliative dermatitis, leukocytoclastic vasculitis, alopecia and photosensitivity (not known)
  • Cardiac failure (uncommon); congestive heart failure and bradycardia (not known); dyspnoea and cough (common)
  • Hepatic failure and hyperbilirubinaemia (uncommon); serious hepatotoxicity including some cases of fatal acute liver failure (not known)
  • Hypersensitivity (uncommon); serum sickness, angioneurotic oedema and anaphylactic reaction (not known); hypokalaemia, leukopenia and thrombocytopenia (uncommon)

Interactions

  • Itraconazole and its major metabolite hydroxy-itraconazole are potent CYP3A4 inhibitors and inhibitors of the drug transporters P-glycoprotein and BCRP, so itraconazole can markedly increase (or sometimes decrease) concentrations of many concomitant drugs
  • Increased concentrations of co-administered drugs may cause severe or life-threatening reactions — e.g. QT prolongation, torsade de pointes, respiratory depression, hepatic reactions, hypersensitivity, myelosuppression, hypotension, seizures, angioedema, atrial fibrillation, bradycardia, priapism
  • Co-administration of a number of CYP3A4 substrates is contraindicated outright (see contraindications list)
  • Reduced concentrations of concomitant drugs may reduce their efficacy — check the approved product labelling of each co-prescribed drug before starting itraconazole
  • Absorption is formulation-dependent: capsules require a full meal, the oral solution requires an empty stomach — do not interchange the two preparations

Clinical monograph

How it works

It inhibits fungal ergosterol synthesis, impairing the fungal cell membrane.

Prescribing in practice

  • It is a strong CYP3A4 inhibitor with many serious interactions (e.g. with some statins, certain other drugs) — review co-medication.
  • It has a negative inotropic effect — avoid in heart failure or a history of it.
  • Hepatotoxicity can occur; capsule absorption needs stomach acid and food (the oral solution differs).

Monitoring

Consider liver function with longer courses; review interactions and cardiac status.

Counselling the patient

  • Take capsules with food.
  • Tell your clinician about all other medicines, as itraconazole interacts with many.
  • Report breathlessness or ankle swelling, or yellowing of the skin/eyes.

Evidence & guidelines

Used for dermatophyte, candidal and some systemic fungal infections, with attention to interactions and cardiac effects.

Reference: MHRA Drug Safety Update (Heart failure); BAD Onychomycosis Guidelines 2014; NICE CKS Fungal Nail Infection; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.