Balversa (Erdafitinib) Medication Guide: What You Should Know Before Taking

Preparations and Precautions Before Taking Erdafitinib

Before taking erdafitinib, be sure to inform your healthcare provider of all your health conditions. Special attention should be given to the following: if you have any vision or eye problems, please let them know in advance. If you are pregnant or plan to become pregnant, you must also clearly inform your provider, as erdafitinib may harm an unborn baby and you should not become pregnant during treatment. For women who can become pregnant, your doctor may perform a pregnancy test before starting treatment. You should use effective contraception during treatment and for one month after the last dose. If you become pregnant or suspect you might be pregnant, tell your doctor immediately. For men with female partners of childbearing potential, effective contraception should also be used during any sexual activity while on treatment and for one month after the last dose. Additionally, if you are breastfeeding or plan to breastfeed, please note that you should not breastfeed during treatment and for one month after the last dose.

Drug Interactions with Erdafitinib

You need to tell your healthcare provider about all the medications you are taking, including prescription drugs, over‑the‑counter medicines, vitamins, and herbal supplements. This is because certain drugs may interact with erdafitinib, affecting its effectiveness or increasing the risk of side effects. For example, some medications that affect liver metabolic enzymes (such as CYP450) may change the concentration of erdafitinib in your body. Therefore, a complete list of your medications is essential for ensuring safe treatment. Do not start or stop any medication without consulting your doctor.

Key Monitoring Indicators During Erdafitinib Treatment

While taking erdafitinib, your doctor will closely monitor your health. First, your blood phosphate level will be checked 14 to 21 days after you start treatment, and then monthly thereafter. This is because a common and potentially serious side effect of erdafitinib is an excessively high level of phosphate in the blood (hyperphosphatemia), which may lead to abnormal deposition of minerals such as calcium in various tissues of the body. Depending on your blood phosphate level, your doctor may recommend dietary adjustments, prescribe phosphate‑lowering medications, or modify or even stop erdafitinib treatment. Additionally, because eye problems are also common, your doctor will arrange for you to see an eye specialist. While awake, you should use artificial tears, moisturizing or lubricating eye gels, or ointments at least every two hours to help prevent dry eyes.