Cancer drugs A to Z list
Erdafitinib is a type of . You pronounce it as eer-da-fit-i-nib.
It is a treatment for some people with cancer that starts in the cells lining the (urothelial cancer) that:
cannot be removed with surgery (unresectable) or has spread elsewhere in the body (metastatic cancer)
has a change () in the fibroblast growth factor receptor 3 (FGFR3) - your doctor checks for this change before you start treatment
You may also have erdafitinib as part of a .
Urothelial cancer that starts in the bladder is a type of bladder cancer. Cancer that starts in the or middle of the kidney (renal pelvis) is called upper urinary tract urothelial cancer.
Find out about your cancer type from our A to Z list
Erdafitinib is a targeted cancer drug. It is a type of cancer growth blocker called a tyrosine kinase inhibitor (TKI). Tyrosine kinases are proteins that cells use to signal to each other to grow.
Erdafitinib works by blocking the tyrosine kinase proteins made by the changed FGFR3 gene. This stops or slows down the growth of the cancer.
Read more about cancer growth blockers
You take erdafitinib as a tablet. You swallow it whole with a glass of water.
You should take the right dose, not more or less.
Talk to your healthcare team before you stop taking a cancer drug, or if you miss a dose.
You usually take erdafitinib once a day. Try and take it at the same time every day.
You continue taking erdafitinib for as long as the treatment works and you are not experiencing too many side effects.
You have blood tests before and during your treatment. They check your levels of and other substances in the blood. They also check how well your liver and kidneys are working.
Before treatment starts you may have a blood test to check for viruses such as hepatitis B, hepatitis C, and HIV. This is called a viral screen.
It’s important for your doctor to know if you have had any of these viruses. This is because this treatment can weaken your and can cause the virus to become active again (reactivation).
You also have tests on your eyes before and during your treatment. And you may have an (electrocardiogram).
Side effects can vary from person to person. They also depend on what other treatments you're having.
Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:
you have severe side effects
your side effects aren’t getting any better
your side effects are getting worse
Early treatment can help manage side effects better.
We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.
Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.
These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:
You might be breathless and look pale due to a drop in . This is called anaemia.
You may have changes in the levels of minerals and salts in your blood. This includes high levels of phosphate and low levels of sodium.
Occasionally you might get low levels of phosphate or low levels of calcium.
Your doctor will ask you to have regular blood tests to check these levels.
Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a , you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.
Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain . But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables.
Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.
Mouth sores and ulcers can be painful. It helps to keep your mouth and teeth clean, drink plenty of fluids and avoid acidic foods such as lemons. Chewing gum can help to keep your mouth moist. Tell your doctor or nurse if you have ulcers.
A dry mouth is also called xerostomia (pronounced zero-stow-mee-a). Talk to your healthcare team if you have this. They can give you artificial saliva to help with a dry mouth. It can also help to drink plenty of fluids.
You might not feel like eating and may lose weight. Eating several small meals and snacks throughout the day can be easier to manage. You can talk to a dietitian if you are concerned about your appetite or weight loss.
Your skin may become dry. And the skin on your hands and feet may become sore, red or may peel. You may also have tingling, numbness, pain and dryness. This is called hand-foot syndrome or palmar plantar syndrome.
Occasionally you may get itching, or a rash. The skin might crack or split. Or your skin might peel, become thick in places or you may develop an abnormal area that is different to the surrounding skin. Rarely you may notice your skin getting thinner.
Try to avoid perfumes and perfumed toiletries, cover up and use sunscreen when in the sun and moisturise your skin regularly. Your healthcare team can tell you which moisturiser and sunscreen to use.
Find out more about protecting your skin from the sun
Erdafitinib can cause fluid to build up in the eye. This can make the lining of the inner parts of the eye, or the jelly like substance inside (vitreous humour) come loose. Doctors call this detachment. It can cause symptoms such as changes to your eyesight, seeing things floating in your vision or flashes of light and pain in your eye.
Erdafitinib can also cause your eyes to be dry. Your doctor may give you eye drops to help with this.
Occasionally you might get eye , a sore in your eye, cloudiness over your eye (cataract) or watery eyes. You can also get an infection in your eye (conjunctivitis) or of your eyelid.
You should not drive or operate machinery if you have any changes to your eyesight.
is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a laxative if needed.
Taste changes may make you go off certain foods and drinks. You may also find that some foods taste different from usual or that you prefer to eat spicier foods. Your taste gradually returns to normal a few weeks after your treatment finishes.
You may have some hair loss or hair thinning. This can be upsetting. Your hair might grow back once treatment has finished.
This is usually mild. You can do things to help yourself, including some gentle exercise. It’s important not to push yourself too hard and eat a well balanced diet.
Talk to your doctor or nurse if this effect is stopping you from doing your usual daily activities.
You might have changes in how your liver works.
Occasionally your liver may not work as well as normal or the cells can be damaged. You can also get high levels of in your blood.
You have regular blood tests to check how well your liver is working.
Your nails may become thicker, discoloured, change shape or separate from the nail bed. Or you may get an infection around the nail.
Occasionally you may find your nails break easily, are painful or develop ridges. And you can get bleeding around the nail bed. But this is rare.
Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.
It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.
Your blood tests might show that you have high levels of a substance called creatinine. This is a waste product made by the muscles. The kidneys remove this from our blood and get rid of it in our urine.
Occasionally your kidneys can stop working or may be damaged. Symptoms include feeling very tired, having swollen ankles, feet or hands, feeling short of breath and feeling sick. You might also have blood in your pee, need to pee more often including during the night or have difficulty peeing. Let your healthcare team know if you have any of these changes.
You have regular blood tests to check how well your kidneys are working.
To try and stop a nose bleed hold your nose tightly just above your nostrils and lean forward slightly. Do this for about 10 to 15 minutes. You can still breathe through your mouth. Contact your advice line if you keep getting nose bleeds or it doesn't stop.
Tell your doctor or nurse if you have this. They can check for the cause of the pain and give you medicine to help.
These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:
higher levels of hormones made by your – symptoms include feeling very thirsty, peeing a lot and tummy symptoms such as constipation
the inside of your nose feeling dry
indigestion - symptoms include heartburn, bloating and burping
These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:
dryness in the body tissues that make – these include the and
a build up of calcium in the blood vessels that can cause blood clots, skin changes and infection. Blood clots can be life threatening; signs are pain, redness and swelling where the clot is. Feeling breathless can be a sign of a blood clot in the lung. Contact your advice line or doctor straight away if you have any of these symptoms
This is a new drug in cancer treatment. So there is limited information available at the moment about possible rare and longer term effects that it may cause. Tell your doctor if you notice anything that is not normal for you.
We have more information about side effects and tips on how to cope with them.
Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.
Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.
It is not known whether this treatment affects in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.
This drug may harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you are having treatment with this drug and for at least 1 month afterwards.
Erdafitinib may stop contraception such as the pill, injection or implant from working properly. If you are using these types of contraception, you should also use a barrier method such as condoms during treatment and for at least 1 month after.
Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner become pregnant while having treatment.
It is not known whether this drug comes through into the breast milk. Doctors usually advise that you do not breastfeed during this treatment and for 1 month after your last dose.
If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.
Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having.
Ask your doctor or pharmacist how long you should avoid live vaccinations.
In the UK, live vaccines include rubella, mumps, measles, BCG, and yellow fever.
You can usually have:
other vaccines, but they might not give you as much protection as usual
the flu vaccine (as an injection)
the coronavirus (COVID-19) vaccine
Talk to your doctor or pharmacist about the best time to have a vaccine in relation to your cancer treatment.
You can be in contact with other people who have had live vaccines as injections. If someone has had a live vaccine by mouth or nasal spray there may be a small risk the vaccine virus can be passed onto you if your is weakened.
Your healthcare team will let you know if you need to take any precautions if you are in close contact with someone who has had a live vaccine.
For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.
You can report any side effect you have to the Medicines and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.
Last reviewed: 20 Apr 2026
Next review due: 20 Apr 2029
Bladder cancer is cancer that starts in the lining of the bladder. The bladder is part of the urinary system, which filters waste products out of your blood and makes urine. Find out about the symptoms, how you are diagnosed, treatment, living with bladder cancer and follow up.
Upper urinary tract urothelial cancer is a rare type of cancer of the lining of the kidney or ureter. Upper urinary tract urothelial cancer can start in a part of the kidney called the renal pelvis. Or it can start in the ureters.
Cancer growth blockers are also called cancer growth inhibitors. They are a type of targeted cancer drug. They aim to stop cancer cells from growing. There are many different types.
Cancer drugs have side effects and these can vary from person to person. But there are things that you can do to help you cope.
Coping with cancer can be difficult. There is help and support available. Find out about the emotional, physical and practical effects of cancer and how to manage them.
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