An oral azole antifungal
Itraconazole
An oral antifungal for nail, skin and deeper fungal infections; it has many drug interactions and needs care in heart and liver problems.
What is Itraconazole?
Itraconazole is an azole antifungal taken by mouth to treat fungal infections, including fungal nail infections and certain stubborn skin, mouth or throat infections. It works by stopping the fungus from growing.
Education and reference only. This is a plain-language guide to Itraconazole — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Itraconazole is an "azole" antifungal taken by mouth to treat fungal infections — including fungal nail infections, certain stubborn skin and mouth or throat fungal infections, and some deeper, more serious systemic fungal infections. It is reserved for infections that need an oral antifungal rather than a simple cream, partly because it can interact with many other medicines and needs some monitoring. In the UK and US the active ingredient and the original brand (Sporanox) are the same; generic itraconazole is identical.
How it works
Fungi rely on a substance called ergosterol to build and maintain their cell membranes. Itraconazole blocks an enzyme the fungus uses to make ergosterol, so the membrane becomes weak and leaky and the fungus cannot grow or survive. This is the same broad principle as other azole antifungals. Because the body uses related enzyme systems to process many medicines, itraconazole also interferes with how those medicines are broken down — which is why it has so many drug interactions. Its absorption from the gut depends on stomach acid and on whether it is taken with food, so it is taken in a way that helps it absorb properly.
Company & origin
Originated / developed by: Janssen Pharmaceutica.
Itraconazole, a triazole antifungal, was discovered by Janssen Pharmaceutica (Belgium) in the late 1970s/1980s and was approved by the US FDA in 1992, marketed as Sporanox.
Practical use
How to take Itraconazole
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take itraconazole capsules with food, ideally after a meal, as this helps the body absorb it; an acidic drink can also aid absorption of the capsules.
- Tell your prescriber and pharmacist about all your other medicines, as itraconazole interacts with a large number of drugs.
- Do not take it if you have heart failure, and report breathlessness or swollen ankles, as it can affect the heart's pumping.
- Report dark urine, yellowing of the skin or eyes, or persistent sickness, as these can signal a liver problem.
- Complete the full course, including any nail-infection treatment, even though improvement can take time.
Weighing it up
Advantages & disadvantages of Itraconazole
Advantages
- Effective oral treatment for a range of fungal infections, including nail infections.
- Can be taken as short, repeated courses for nail problems rather than continuously.
- Reaches and stays in skin and nails well.
- A well-established option when topical antifungals are not enough.
Disadvantages
- Interacts with many other medicines, so a careful medicines check is essential.
- Should not be used in people with heart failure because it can worsen the heart's pumping.
- Can affect the liver, so symptoms of liver problems must be watched for.
- Absorption depends on taking it correctly, and it can cause stomach upset.
Practical use
Good to know
Two things matter most in everyday use. First, interactions: itraconazole can sharply raise the levels of many other medicines or be affected by them — for example, certain statins must be stopped while taking it, and some heart-rhythm and other medicines must not be combined at all — so it is essential your prescriber and pharmacist see your full medicine list, including anything bought over the counter. Second, how you take it affects how well it is absorbed: the capsule form is taken with food and is affected by stomach-acid-lowering medicines, while a liquid form is taken differently — follow the specific instructions for your product. It can rarely affect the liver, so report unusual tiredness, nausea, dark urine or yellowing of the skin or eyes, and it can worsen heart failure, so any new breathlessness or ankle swelling should be reported.
Who should not take it / use with caution
- People with heart failure or a history of it should generally not take it, as it can weaken the heart's pumping (a "negative inotropic" effect).
- It must not be combined with certain medicines — including some that affect the heart's rhythm and some others — because the combination can be dangerous; a full medicine review is essential first.
- Used with caution in significant liver disease, and avoided in pregnancy (and care in breastfeeding), where the need is weighed individually.
Monitoring
- Response of the infection (which can be a long course for nails)
- Liver blood tests, especially with longer courses or liver concerns
- For signs of heart failure (breathlessness, ankle swelling) and a full interaction check
Side effects
- Nausea, indigestion, tummy upset, diarrhoea and headache are among the more common effects.
- Swelling of the ankles, breathlessness or other signs of fluid overload can signal an effect on the heart — report these.
- Rarely, liver problems (report unusual tiredness, nausea, dark urine or yellowing of the skin or eyes), nerve tingling, or serious skin reactions.
Key interactions
- It has many important interactions: certain statins (such as simvastatin) must be stopped while taking it, and several other medicines must not be combined at all.
- Medicines that lower stomach acid (and antacids) can reduce absorption of the capsule, so timing or a different form may be needed.
- It can raise the levels of many medicines processed by the liver — including some blood thinners, heart, sedative and immune medicines — so the full medicine list must be checked.
Available as: Capsules and an oral liquid (which are taken differently and are not directly interchangeable), and a form used in hospital for serious infections.
Answers
Itraconazole: frequently asked questions
Why does itraconazole interact with so many other medicines?
Itraconazole blocks an enzyme system in the liver that the body also uses to break down many other medicines. This can cause those medicines to build up to higher-than-intended levels — sometimes dangerously. That is why your prescriber and pharmacist need your full medicine list, including anything bought over the counter, before you start.
Do I really have to stop my statin while taking it?
For some statins, yes. Itraconazole can sharply raise the levels of certain statins (such as simvastatin), increasing the risk of muscle injury, so they are paused during the course. Your prescriber will tell you which of your medicines to stop, adjust or keep — do not change anything without checking.
Should I take it with food?
It depends on the form. The capsule is absorbed better when taken with food and can be affected by stomach-acid-lowering medicines, whereas the liquid form is taken differently. Follow the specific instructions for your product, as taking it the wrong way can stop it working properly.
Why does it matter if I have heart problems?
Itraconazole can weaken the heart's pumping action, so it is generally avoided in people with heart failure or a history of it. Report any new breathlessness, ankle swelling or unusual tiredness while taking it, as these can be signs of fluid building up.
What is the difference between itraconazole and Sporanox?
They are the same medicine — itraconazole is the generic (active-ingredient) name and Sporanox is the original brand name, used in both the UK and US. Generic itraconazole contains the identical active ingredient, though capsule and liquid forms are taken differently.
The wider class
About Azole antifungals
Itraconazole belongs to the azole antifungals class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF: Itraconazole.
- electronic Medicines Compendium (SmPC): Itraconazole (Sporanox).
- NICE CKS: Itraconazole.
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