When two or more medicines are taken at the same time, the effects of one of the medicines can be altered by the other. This is known as a drug-drug interaction. Some antifungal medicines can interact with other medicines.

Tell your GP or pharmacist what other medicines you are taking, including over-the-counter medicines, so they can decide whether an antifungal medicine is safe for you to take.

Medicines that antifungal medicines may interact with include:

• benzodiazepines – a group of medicines used to help sleep and reduce anxiety
• ciclosporin – a medicine that suppresses the immune system (the body’s natural defence against illness and infection)
• cimetidine – a medicine used to treat indigestion
• hydrochlorothiazide – a medicine used to treat high blood pressure (hypertension) 
• oestrogens – hormones found in some contraceptives
• phenytoin – a medicine used to treat epilepsy
• progestogens – hormones found in some contraceptives
• rifampicin – an antibiotic used to treat bacterial infections, such as tuberculosis 
• tacrolimus – a medicine that suppresses the immune system
• theophylline – a medicine used to treat asthma
• tricyclic antidepressants – medicines used to treat depression
• zidovudine – a medicine used to treat HIV and AIDS

Antifungal medicines are used to treat fungal infections.

Fungal infections

Fungi are plant-like organisms that feed by breaking down living tissue.

Fungi that cause infections in humans are known as dermatophytes. Dermatophytes are particularly attracted to a type of tissue called keratin, which is a tough, waterproof tissue found in many parts of the body such as in the:

• nails
• hair
• skin’s outer surface

This explains why fungal infections often occur on the skin, nails and scalp.

Common fungal infections

Antifungal medicines may be used to treat the following common fungal infections:

• ringworm – which causes a ring-like red rash on the skin of the body or scalp
• athlete’s foot – which affects the skin on the feet, causing it to become red, flaky and itchy
• fungal nail infection – which causes the toenails or fingernails to become thickened and discoloured, and sometimes brittle, with pieces of nail breaking off
• vaginal thrush – which causes irritation and swelling of the vagina and vulva (the female external sexual organs)

Invasive fungal infections

Invasive fungal infections are a less common, but more serious, type of fungal infection. They are infections that occur deep inside the body’s tissue or in one of the organs, such as in the:

• brain – for example, fungal meningitis, where a fungus causes an infection of the protective membranes that surround the brain and spinal cord
• lungs – for example, aspergillosis, which is a lung infection caused by a fungal mould called aspergillus

People with a weakened immune system (the body’s natural defence system) are particularly vulnerable to invasive fungal infections. Those at risk include:

• people with HIV and AIDS
• people having high-dose chemotherapy to treat cancer
• people who are taking immunosuppresants – medicines to suppress the immune system (the body’s natural defence against infection and illness), often used after an organ transplant

How antifungal medicines work

Antifungal medicines work by either:

• killing the fungal cells – for example, by affecting a substance in the cell wall, causing the contents of the cell to leak out and the cell to die
• preventing the fungal cells from growing and reproducing

Types of antifungal medicines

Antifungal medicines are used in several ways, depending on your specific fungal infection. The main types of antifungal medicines include:

• topical antifungals, applied to the skin, hair or nails
• oral antifungals, swallowed in capsule, pill or liquid form
• intravenous antifungals, injected into your bloodstream

Read more about the types of antifungal medicines.

Things to consider

Before taking antifungal medicines, there are various things to consider, such as any existing conditions or allergies that may affect your treatment for fungal infection.

Read more about special considerations for antifungal medicines.

Side effects

As with all medicines, antifungal medicines have side effects. These depend on the type of medication you’re taking. In most cases, the side effects are mild and only last a short time, but there are rare cases of more serious problems.

Common side effects include:

• irritation of the skin
• diarrhoea 
• feeling sick
• indigestion 

In rare cases, liver damage can occur as a result of using antifungal medicines.

Read more about the side effects of antifungal medicines.

Interactions with other medicines

When two or more medicines are taken at the same time, they can sometimes affect how each other works, this is known as interaction.

There are several medicines that can interact with antifungal medicines.

Read more about medicines that can interact with antifungal medicines.

Dosage

Your GP or pharmacist should advise on how to take or use your antifungal medicine. For further information, see the patient information leaflet that comes with your medicine or the Medicines information tab above.

Speak to your GP or pharmacist if you take too much of your antifungal medicine. You may be advised to visit your nearest hospital’s accident and emergency (A&E) department. If you are advised to go to hospital, take the medication’s packaging with you so that the healthcare professionals who treat you know what you have taken.

Antifungal medicines have many brand names as they are made by different pharmaceutical manufacturers.

There are also many different types of antifungal medicines, including:

• clotrimazole
• econazole nitrate 
• miconazole 
• terbinafine
• fluconazole
• ketoconazole
• amphotericin

The packaging should state what antifungal medicine the product contains and how much. This may be shown as a percentage – for example, cream containing 1% clotrimazole, or in milligrams (mg) – for example, capsules containing 50mg of fluconazole.

Types of antifungal medicines

Antifungal medicines are available as:

• topical antifungals – a cream, gel, ointment or spray applied directly to the body
• oral antifungals – a capsule, tablet or liquid medicine that is swallowed
• intravenous antifungals – an injection into a vein in your arm, usually in hospital through an intravenous infusion (a continuous drip of medicine through a narrow tube)

Antifungal intravaginal pessaries are also available. Pessaries are small suppositories inserted into the vagina to treat conditions such as vaginal thrush.

Antifungal medicines can cause side effects. These will differ depending on the type of antifungal medicine you are using.

Side effects of topical antifungals

Topical antifungal medicines, such as creams, can cause:

• itching
• a mild burning sensation
• redness

Stop using the medicine if any of these side effects are severe and see your GP or pharmacist to find an alternative.

Side effects of oral antifungals

Side effects of oral antifungals, such as capsules, include:

• feeling sick
• abdominal (tummy) pain
• diarrhoea 
• flatulence (wind)
• headache
• a rash
• indigestion 

These side effects are usually mild and only last for a short period of time.

Antifungals can also cause severe reactions, such as:

• an allergic reaction – swelling of your face, neck or tongue or difficulty breathing
• a severe skin reaction – such as peeling or blistering skin

If you experience any of these reactions, stop taking your medicine and contact your GP immediately.

If you are having difficulty breathing, visit the accident and emergency (A&E) department of your nearest hospital or call 999 for an ambulance.

Liver damage from antifungal medicines

Liver damage is a rare, but more serious, side effect of oral antifungals.

Stop taking your medicine and contact your GP if you experience:

• loss of appetite
• vomiting
• feeling sick for a long time
• jaundice – yellowing of your skin or the whites of your eyes 
• unusually dark urine or pale faeces (stools)
• unusual tiredness or weakness

Side effects of intravenous antifungals

Amphotericin B is the most commonly used intravenous antifungal. This is usually given in hospital as an intravenous infusion (a continuous drip of medicine into a vein in your arm).

Side effects of amphotericin include:

• loss of appetite 
• feeling sick
• vomiting
• diarrhoea
• epigastric pain (pain in the upper part of your tummy)
• a high temperature (fever)
• chills
• headache 
• muscle and joint pain
• anaemia (a reduced number of red blood cells)
• a rash

Amphotericin can also affect your:

• kidneys – causing abnormally low levels of some minerals in your blood, such as potassium or magnesium  

More rarely it can cause problems with your

• heart – causing an irregular heartbeat or changes in your blood pressure
• liver – affecting the way your liver functions, for example, causing a build-up of bilirubin in the blood; bilirubin is a yellow substance that is produced when red blood cells are broken down  

As amphotericin is given in hospital under supervision, any adverse effects are usually quickly detected and treated.

Antifungal medicine interactions with other medicines

Before you take antifungals there are a number of things you should discuss with your GP.

Allergies

You are generally advised not to take an antifungal medicine if you are allergic to the medicine or any of the ingredients used in it.

In some cases, such as when treating invasive fungal infections in hospital, your doctors may feel the benefit of the medicine outweighs the risk of an allergic reaction. They may decide to use the medicine and monitor you closely.

Other conditions

Be careful with some oral antifungals if you have problems with your heart, liver or kidneys.

Discuss your condition with your GP or pharmacist to find out which antifungal medicines are safe for you to use.

Topical antifungals

If you are using a topical antifungal medicine, such as a cream, avoid it coming into contact with:

• your eyes 
• moist linings (mucous membranes), for example, inside your nose or mouth (unless it is a gel that is supposed to be used in your mouth)

Contraceptives

Some antifungal medicines are designed to be used on a man’s penis or in or around a woman’s vagina. Antifungal creams or  vaginal suppositories (pessaries) are sometimes used to treat thrush.

However, these types of antifungal medicines can damage latex condoms and diaphragms, making them less effective. Use a different method of contraception while you are using the antifungal medicine, or avoid having sex.

Some types of antifungal medicines can also interact with oestrogens and progestogens, which are found in some types of hormonal contraceptives, such as the combined contraceptive pill. You may experience some breakthrough bleeding while taking your antifungal medicine, but your contraceptive protection should not be affected.

Only oral antifungal medicines interact with oestrogens.

Pregnancy

Many antifungal medicines are not suitable to take during pregnancy. Check the patient information leaflet that comes with your medicine to find out.

However, if you have vaginal thrush during pregnancy, your GP may prescribe an antifungal suppository that can be inserted into your vagina (a pessary) or an antifungal cream.

Breastfeeding

Small amounts of some medicines can pass into your breast milk and may then be passed on to your baby if you are breastfeeding. Check the patient information leaflet that comes with your antifungal medicine, as many medicines should not be taken while breastfeeding.