Itraconazole (Itraconazole Capsules/Tablets) — Patient Information (UK)

Itraconazole is an antifungal medicine used to treat a range of fungal infections. It works by targeting the fungal cells’ ability to produce essential substances needed for growth and survival. This page explains how itraconazole works, how it is used, important interactions, and safety advice to help you use your medicine more confidently.

Brand names and formulations may vary (for example capsules or modified-release capsules depending on product). Always follow the instructions provided with your specific medicine.

1. Basic product information

2. How itraconazole works (mechanism of action)

Itraconazole belongs to the triazole class of antifungals. It works by inhibiting an enzyme called lanosterol 14α-demethylase (a key step in fungal cell membrane formation). Without proper membrane production, the fungus cannot grow effectively and is gradually cleared by the immune system.

Itraconazole is active against many common fungi such as dermatophytes (e.g., causing some nail or skin infections) and Candida and Aspergillus species (depending on the infection and sensitivity).

3. Pharmacokinetics (how the body absorbs and processes it)

Understanding pharmacokinetics can help explain why food and timing matter. Itraconazole has variable absorption and may interact strongly with other medicines.

Absorption

• Food can affect absorption: Some itraconazole capsule products are absorbed more effectively when taken with food. This is why instructions may specify taking the capsules with a meal (often a full meal).
• Acid strength matters: Medicines that reduce stomach acid may reduce absorption for certain formulations. If you take antacids, proton pump inhibitors (PPIs) or H2 blockers, ask for product-specific advice.

Distribution

Itraconazole concentrates in certain tissues. For example, after starting treatment, measurable drug levels can persist for some time, which can be helpful for long-lasting fungal infections such as nail infections. However, the time it takes to see improvement can still be slow, because infected material may need to grow out or fully resolve.

Metabolism and elimination

• Itraconazole is mainly metabolised by the liver (involves enzymes such as CYP3A4).
• It is eliminated primarily through the liver and bile, with some excretion via urine depending on the individual and formulation.
• Because it is metabolised by liver pathways, other medicines that affect these pathways can significantly increase or decrease itraconazole levels.

4. Typical uses (what itraconazole is used for)

Itraconazole is used to treat fungal infections. The exact indication depends on the type of fungus, where it is in the body, and how severe the infection is.

Examples of conditions itraconazole may be prescribed/used for

• Fungal nail infections (onychomycosis) and other difficult-to-treat fungal infections of the skin
• Cutaneous (skin) fungal infections caused by susceptible fungi
• Vulvovaginal candidiasis may be considered in selected situations, depending on the causative organism and treatment plan
• Infections caused by Aspergillus or other invasive fungi in specialist settings (these usually require close monitoring due to complexity and risk)
• Other fungal infections where an azole antifungal is appropriate, based on local guidance and the suspected/confirmed fungus

If you’re unsure whether itraconazole is suitable for your specific infection, check the label/instructions for your product and speak with a healthcare professional.

5. Timing and how to take itraconazole

The key practical points are consistent timing and (for some products) taking it with food. Always follow the instructions that came with your medicine.

General timing tips

• Take at the same time each day to keep blood levels steadier.
• Food guidance: Some itraconazole capsule products should be taken immediately after a full meal. If your leaflet says “take with food,” do so to help absorption.
• Swallow whole: Do not crush or open capsules unless your product instructions specifically allow it.
• Don’t stop early: Even if symptoms improve, the infection may not be fully cleared. Complete the planned course unless you’re advised to stop.

Missed dose

If you miss a dose, take it when you remember unless it is close to the time for the next dose. Do not take a double dose to make up for a missed one. If you’re unsure, check the patient leaflet or seek advice.

6. Food interactions and stomach-acid effects

Food and stomach acid can influence how much itraconazole gets absorbed into the bloodstream, especially for some capsule formulations.

What to know

• Take with food (often required): If your product leaflet says to take with a meal, do not take it on an empty stomach. This can improve reliability of absorption.
• Acid-lowering medicines: Medicines that reduce stomach acid may reduce itraconazole absorption for certain formulations. Examples include:
  • Proton pump inhibitors (PPIs) (e.g., omeprazole, lansoprazole)
  • H2 blockers (e.g., famotidine)
  • Antacids
• Timing separation may be needed: Some interactions can be managed by spacing doses, but product-specific guidance is important.

If you regularly take medicines for reflux, indigestion, or heartburn, review them with your pharmacist or healthcare professional.

7. Alcohol interactions

Itraconazole can affect the liver, and alcohol can also stress the liver. For this reason, it’s generally advisable to limit or avoid alcohol while taking itraconazole, especially if you have liver problems or abnormal liver tests.

Practical advice

• If you drink alcohol, consider keeping it minimal and avoid binge drinking.
• If you develop symptoms such as yellowing of the skin/eyes, dark urine, severe fatigue, or persistent nausea, contact a healthcare professional urgently.

8. Medicine interactions (very important)

Itraconazole is well known for significant drug interactions. It affects metabolism pathways (particularly CYP3A4) and can also be affected by other medicines that influence these pathways.

Tell your pharmacist or healthcare professional about all medicines you take, including: prescription medicines, over-the-counter products, herbal remedies, and supplements.

Medicines that may be unsafe with itraconazole

Some medicines should not be used together because they may either: reduce itraconazole levels (making it less effective) or increase itraconazole levels (increasing side effects), or both.

• Strong enzyme inducers (may reduce itraconazole): for example rifampicin, rifabutin, some anticonvulsants (e.g., carbamazepine, phenytoin), and certain others.
• Medicines that can interact at heart rhythm level: some combinations may increase the risk of abnormal heart rhythm (QT prolongation). Always seek professional advice if you take antiarrhythmics or certain antipsychotics or antidepressants.
• Some “statins” and other lipid-lowering drugs: interactions can increase statin levels and side effects. Choice of statin may need adjustment.
• Immunosuppressants and certain cancer therapies: levels can become altered and require careful monitoring.
• Benzodiazepines, opioids, and sedatives: interactions may affect sedation and safety in some cases.

Herbal products

Avoid starting new herbal remedies without advice. Some products can affect liver enzymes and alter itraconazole exposure. A notable example is St John’s wort (Hypericum perforatum), which may reduce itraconazole effectiveness.

Practical interaction checklist

• Bring an up-to-date list of your medicines to your pharmacist.
• Include inhalers and creams too (sometimes they still signal broader disease/medication patterns).
• If you recently stopped a medicine, mention that as well.
• If you have had prior reactions to antifungals or other azoles, tell your healthcare professional.

9. Indications (what condition it treats) and expectations

“Indication” means the specific condition(s) the medicine is intended to treat. Itraconazole can be used for various fungal infections, depending on the organism and severity.

Important expectations

• Improvement can be gradual: For nail infections, even after fungus is suppressed, the infected nail may take months to grow out.
• Skin rashes may calm down first: Visible symptoms can improve before the deeper infection is fully resolved.
• Complete the course: Stopping early increases the risk of relapse.

If symptoms worsen or you don’t see improvement within the expected timeframe, contact a healthcare professional.

10. Dosing (how much to take)

Dosing depends on the type of fungal infection, severity, the specific itraconazole formulation, and your health status (including liver function). Always use the dose stated on the label or the dose schedule given to you for your particular infection.

Common dosing principles

• Daily frequency: It may be taken once or twice daily depending on the condition.
• Course length: Some infections require short courses; others require longer treatment.
• Formulation differences: Different itraconazole capsule types can have different absorption characteristics.

Example schedules (general information)

Product-specific instructions are essential. Below are illustrative examples of what dosing plans may look like, not a substitute for your own label:

• Skin or nail infections: dosing schedules may vary from daily continuous treatment to intermittent regimens depending on the infection and product.
• More serious fungal infections: dosing is typically higher and requires close medical supervision.

If you want, tell us your diagnosis and your exact product strength and form (e.g., “itraconazole 100 mg capsules”) and we can help you understand the dosing instructions on your pack in a general, educational way.

11. Safety profile and who should take extra care

Like all medicines, itraconazole can cause side effects. Many people tolerate it well, but some situations require caution.

Common side effects

• Nausea, stomach upset
• Headache
• Diarrhoea
• Skin reactions or rash in some people
• Feeling tired

Serious side effects (seek urgent advice)

• Signs of liver problems: yellowing of the eyes/skin, dark urine, severe fatigue, persistent nausea or vomiting, or upper abdominal pain. Contact a healthcare professional promptly.
• Severe allergic reactions: swelling of the face/lips, difficulty breathing, or widespread rash with fever. Seek urgent care.
• Heart-related symptoms: chest pain, sudden shortness of breath, fainting, or rapid heartbeat. This is particularly important if you have a history of heart failure.

Heart failure warning (important)

Itraconazole has been associated with increased risk of heart failure in some individuals, particularly those with existing heart failure. If you have or have had heart failure, discuss this urgently with a healthcare professional before starting. Don’t ignore symptoms such as breathlessness or swelling in the legs.

Liver monitoring

Your clinician may consider liver blood tests, especially if treatment is prolonged or if you have existing liver disease. Follow advice about any scheduled monitoring.

Pregnancy and breastfeeding

If you are pregnant, planning pregnancy, or breastfeeding, speak to a healthcare professional. The appropriateness of itraconazole depends on the infection, severity, and available alternatives.

Use in children

Dosing and safety in children can differ and depend on formulation and the specific condition. Use only under appropriate medical guidance.

12. Practical use tips (how to get the best results)

• Keep taking it consistently: Missing doses may reduce effectiveness.
• Support absorption: If your product says to take with food, do so. Avoid taking on an empty stomach.
• Know your other medicines: Make sure your pharmacist has a complete list to check for interactions.
• Track symptom progress: For nails and skin, improvement can take weeks. If you’re not improving, check in.
• Hygiene and prevention: Keep affected areas clean and dry. Use separate towels. In nail infections, good nail hygiene and avoiding shared nail tools can help reduce reinfection.
• Don’t share antifungal creams or products: Fungal infections can be misdiagnosed, and mixing treatments can complicate care.

13. Missed dose, overdose and what to do

If you miss a dose

Take it when you remember, unless it’s nearly time for the next dose. Do not take two doses at once.

If you take too much

If an overdose is suspected, seek medical advice urgently. In the UK, you can call 111 for non-emergency advice. If there are severe symptoms (such as fainting, severe dizziness, or breathing problems), seek emergency help.

14. Alternative options (what else may be used)

Depending on the type of fungal infection, alternatives may include other antifungal medicines. Options can differ by location of infection, suspected fungus, your medical history, and potential interactions.

Common alternatives by infection type

• Terbinafine (often used for dermatophyte skin and nail infections; sometimes a preferred option for certain nail infections)
• Fluconazole (commonly used for some yeast infections; dosing depends on the indication)
• Topical antifungals (creams, sprays, lacquers), particularly for limited skin or nail involvement
• Specialist antifungals for more serious infections may be considered in hospital settings based on the fungus and resistance patterns.

Treatment choice is best made with clinical guidance, especially for complex infections or those that recur.

15. United Kingdom market and legal context

In the UK, access to antifungal medicines depends on the product type, strength, and local supply arrangements. Advice may differ between pharmacy-based supply and specialist care.

How antifungal medicines are used in the UK

• For many fungal conditions, diagnosis matters (for example, nail changes may not always be fungal).
• Antifungals are used according to clinical assessment and relevant guidance, balancing effectiveness and safety.
• Drug interaction screening is especially important for itraconazole due to the potential for serious interactions.

If you have questions about suitability in the UK healthcare context (including monitoring and follow-up), ask your pharmacist or clinician.

16. Recent guidance and clinical considerations (UK-relevant themes)

While specific recommendations can evolve, common UK clinical considerations for systemic azole antifungals typically include:

• Thorough review of medicines: due to strong interactions, screening is essential before starting.
• Assessment of heart and liver risk: particularly in people with pre-existing heart disease or liver concerns.
• Confirming the diagnosis when possible: especially for nail disease, where mimics exist.
• Adherence to formulation instructions: food and absorption requirements can differ by product type.

Your healthcare professional can tailor advice to current local practice and your personal risk factors.

17. Delivery, availability and what to expect from an online pharmacy (UK)

Availability can vary depending on your location, current stock levels, and the specific itraconazole formulation (for example, capsule strengths and any modified-release versions).

Delivery expectations

• Processing time: orders are typically processed during business hours.
• Delivery times: standard delivery may take several working days; express options may be available.
• Tracking: you may receive delivery updates or a tracking link (depending on the service).

How to receive and store

• Check the pack for the correct strength and formulation.
• Store according to label instructions (commonly at room temperature, protected from moisture).
• Keep out of sight and reach of children.

18. FAQ — Frequently asked questions

How long does it take itraconazole to work?

This depends on the infection. Skin symptoms may improve in days to weeks, but nail infections often take much longer. Even after the fungus is controlled, the affected nail may need to grow out, which can take months. If you don’t notice any improvement within the timeframe your clinician discussed, seek advice.

Should I take itraconazole with food?

Many itraconazole capsule products are best absorbed when taken with food. Check your specific patient leaflet and follow the directions on your pack. If your instruction says “take with a meal,” do so for the most reliable effect.

Can I take indigestion tablets or reflux medicine with itraconazole?

Some reflux or indigestion medicines can reduce absorption for certain itraconazole formulations. Examples include proton pump inhibitors and some H2 blockers. Talk to a pharmacist before combining medicines, and do not assume spacing alone is always sufficient.

Is itraconazole safe with alcohol?

Alcohol is not automatically forbidden, but it may increase liver strain. It’s generally wise to limit alcohol during treatment and avoid binge drinking, particularly if you have liver concerns. Stop and seek advice if you develop signs of liver problems.

What medicines should not be taken together with itraconazole?

Several medicines can interact with itraconazole, including some antibiotics/anti-TB medicines, anticonvulsants, certain statins, and medicines that affect heart rhythm or sedation. Always provide a full list of your medicines (including over-the-counter and herbal products) to your pharmacist for interaction screening.

What if I forget a dose?

Take it when you remember unless it is nearly time for the next dose. Do not double up. If unsure, consult your pharmacist or check the patient information leaflet.

Can itraconazole cause liver problems?

Yes, itraconazole can occasionally affect the liver. Serious liver problems are uncommon, but you should seek prompt medical advice if you notice symptoms such as yellowing of the skin/eyes, dark urine, severe fatigue, or persistent nausea/vomiting.

Does itraconazole affect the heart?

In some individuals, especially those with existing heart failure, itraconazole has been linked with increased heart failure risk. If you have heart failure or develop symptoms such as breathlessness, swelling in the legs, or chest pain, seek urgent advice.

What can I do to prevent reinfection?

Reinfection can happen when fungus remains on skin, clothing, or shared items. Keep areas clean and dry, use separate towels, change socks regularly, and avoid sharing nail tools. If you’re treating nails, good nail hygiene and preventing trauma can help.

Are there alternatives to itraconazole?

Yes. Alternatives depend on the infection type and may include other oral antifungals (such as terbinafine or fluconazole) or topical options. A clinician can help choose the best option based on diagnosis, location, and interaction risks.

19. Key takeaways

• Itraconazole is an oral antifungal used for a range of fungal infections.
• Food and formulation matter: follow your pack instructions carefully for best absorption.
• Drug interactions are common: check all medicines (including reflux tablets and herbal products).
• Safety needs attention: be aware of heart failure and liver-related warnings.
• Results can be slow: especially for nail infections—complete the course and allow time for improvement.

If you have questions about whether itraconazole is suitable for your situation, or you’re unsure about interactions with your current medicines, ask a pharmacist for advice before continuing.