Erdafitinib belongs to the class of medications called protein kinase inhibitors.

It is used to treat urothelial cancer, a type of cancer of the bladder, when the cancer has been previously treated with chemotherapy which is no longer working, and has either spread to other parts of the body or cannot be removed by surgery.

This medication works by blocking the action of a group of proteins called fibroblast growth factor receptors (FGFR); proteins that are involved in the growth and spread of cancer cells. In this type of cancer, these receptors are abnormally active. Erdafitinib works by preventing the action of these proteins.

Erdafitinib has been granted a notice of compliance with conditions (NOC/c) by Health Canada. This means that Health Canada has approved this medication to be marketed based on promising evidence of effectiveness, but additional results of studies are needed to verify its effectiveness. An NOC/c is used to allow access to products that are used to treat or prevent serious, life-threatening, or severely debilitating illness.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended starting dose of this medication is 8 mg taken by mouth, once daily. After 14 to 21 days, your doctor may increase or decrease your dose, depending on the results of blood tests and how well the medication is tolerated.

This medication should be taken once daily at approximately the same time every day. It may be taken with food or on an empty stomach. Swallow the tablets whole, do not chew or crush the tablets.

If you vomit after taking a dose, do not take another dose. Take the next dose at the regularly scheduled time.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

3 mg
Each yellow, round, biconvex, film-coated tablet, debossed with "3" on one side and "EF" on the other side, contains 3 mg of erdafitinib. Nonmedicinal ingredients: croscarmellose sodium, magnesium stearate (from vegetable source), mannitol, meglumine, and microcrystalline cellulose; film-coating: glycerol monocaprylocaprate Type I, iron oxide yellow, polyvinyl alcohol partially hydrolyzed, sodium lauryl sulfate, talc, and titanium dioxide.

4 mg
Each orange, round, biconvex, film-coated tablet, debossed with "4" on one side and "EF" on the other side, contains 4 mg of erdafitinib. Nonmedicinal ingredients: croscarmellose sodium, magnesium stearate (from vegetable source), mannitol, meglumine, and microcrystalline cellulose; film-coating: glycerol monocaprylocaprate Type I, iron oxide yellow, iron oxide red, polyvinyl alcohol partially hydrolyzed, sodium lauryl sulfate, talc, and titanium dioxide.

5 mg
Each brown, round, biconvex, film-coated tablet, debossed with "5" on one side and "EF" on the other side, contains 5 mg of erdafitinib. Nonmedicinal ingredients: croscarmellose sodium, magnesium stearate (from vegetable source), mannitol, meglumine, and microcrystalline cellulose; film-coating: ferrosoferric oxide/iron oxide black, glycerol monocaprylocaprate Type I, iron oxide yellow, iron oxide red, polyvinyl alcohol partially hydrolyzed, sodium lauryl sulfate, talc, and titanium dioxide.

Do not take this medication if you are allergic to erdafitinib or any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• changed sense of taste
• constipation
• decreased appetite
• diarrhea
• discoloured nails
• dry eyes
• dry mouth, nose, skin
• fatigue
• hair loss
• infected skin around the nail
• itchy skin rash
• muscle pain
• nausea
• sore throat
• stomach pain
• vaginal dryness
• vomiting
• watery eyes
• weakness
• weight loss

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blood in the urine
• dry eyes
• fever
• mouth sores
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• skin or nail problems (e.g., nail pain, cracked skin, very dry skin, bleeding under the nail, nail separation from the bed)
• skin rash
• swelling or peeling skin of the hands and feet
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)
• vision problems (e.g., blurred vision, vision loss, cloudy vision)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Eye problems: People taking erdafitinib may experience eye problems and vision changes. If you experience changes to your vision such as cloudiness, blurred vision or vision loss, contact your doctor immediately.

Phosphorus levels: This medication can cause higher than normal levels of phosphate in the blood. Your doctor will test for the amount of phosphate in your blood with blood tests while you are taking this medication.

Pregnancy: This medication should not be taken during pregnancy. Erdafitinib may cause severe harm to a developing baby if it is taken during pregnancy. Both females and males must use a reliable method of birth control (e.g., condoms, birth control pill) during treatment and for at least 3 months after treatment is finished. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication may pass into breast milk. If you are breast-feeding and taking erdafitinib, it may affect your baby. Due to the potential for serious harm to a baby if they are exposed to this medication, breast-feeding mothers are advised not use this medication.

Children: The safety and effectiveness of using this medication have not been established for children.

There may be an interaction between erdafitinib and any of the following:

• aluminum hydroxide
• apalutamide
• atogepant
• "azole" antifungals (e.g., fluconazole, itraconazole, ketoconazole, voriconazole)
• benzodiazepines (e.g., alprazolam, triazolam)
• bilastine
• bosentan
• calcium carbonate
• clarithromycin
• cobicistat
• colchicine
• cyclosporine
• dabigatran
• digoxin
• doxorubicin
• edoxaban
• enzalutamide
• estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
• finerenone
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., efavirenz, etravirine)
• HIV protease inhibitors (e.g., atazanavir, darunavir, lopinavir, ritonavir)
• lamivudine
• lemborexant
• lomitapide
• lumacaftor and ivacaftor
• magnesium hydroxide
• metformin
• mifepristone
• mitotane
• modafinil
• nirmatrelvir and ritonavir
• phosphate supplements
• pimozide
• pindolol
• pramipexole
• procainamide
• progestins (e.g., desogestrel, dienogest, drospirenone, levonorgestrel, medroxyprogesterone, norethindrone)
• other protein kinase inhibitors (e.g., ceritinib, dabrafenib, pazopanib)
• rifabutin
• rifampin
• St. John's wort
• seizure medications (e.g., carbamazepine, eslicarbazepine, phenobarbital, phenytoin, primidone)
• sirolimus
• simvastatin
• sodium phosphates
• tacrolimus
• topotecan
• triamterene
• venetoclax
• vincristine
• vitamin D analogues (e.g., alfacalcidol, calcitriol, cholecalciferol)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.