Medical Information

Erdafitinib, as an FGFR inhibitor, commonly has side effects such as hyperphosphatemia, ocular lesions, and gastrointestinal reactions, which need to be managed through dose adjustment, symptomatic treatment, and regular monitoring. The following system elaborates on its side effects, risk classification, and targeted mitigation measures, with a focus on serious adverse reactions that require urgent treatment.

1. Common side effects and alleviation

(1) Hyperphosphatemia: The incidence rate is about 76%, manifested as elevated blood phosphorus. Suggest a low phosphorus diet and oral administration of phosphate binders; When the blood phosphorus level is above 7mg/dL, medication should be suspended and reduced to ≤ 5.5mg/dL before resuming.

(2) Eye lesions: including retinal pigment epithelium detachment (25%) and dry eye syndrome (28%). Use artificial tears for relief and undergo monthly eye examinations; Immediate cessation of medication and evaluation is required for blurred vision.

(3) Stomatitis: The incidence rate is 56%. It is recommended to use mouthwash containing lidocaine and avoid acidic foods; In severe cases, dosage adjustment or treatment interruption is required.

2. Serious side effect management

(1) Nail toxicity: The incidence of nail bed separation is about 13%. Keep nails dry and clean, and avoid damage during trimming; If grade 3 toxicity occurs, medication should be suspended until recovery.

(2) Hepatotoxicity: Elevated ALT/AST accounts for 35%. Monitor liver function before treatment and monthly, and permanently discontinue medication when there is a grade ≥ 3 elevation.

(3) Embryotoxicity: Pregnant women are prohibited from using it. Patients of childbearing age should take effective contraceptive measures during treatment and within one month after discontinuing medication.

3. Management of special populations

(1) Elderly patients: those over 65 years old are more prone to dehydration and renal dysfunction, and electrolyte monitoring needs to be strengthened. The initial dose should be considered to be reduced.

(2) Liver damage patients: Child Pugh B/C grade should be reduced to 6mg per day and avoid combination with strong CYP3A inhibitors.

(3) Patients with kidney damage: When eGFR<30mL/min, close monitoring of blood phosphorus is necessary, and it is recommended to reduce the initial dose by 25%.

4. Comprehensive management strategy

(1) Laboratory monitoring: FGFR mutations, blood phosphorus, liver and kidney function are tested before treatment, blood phosphorus is rechecked on the 14th day and every month, and retina is evaluated every 2 months.

(2) Drug interactions: Avoid using CYP3A strong inducers (such as rifampicin) in combination, and proton pump inhibitors should be taken every 2 hours.

(3) Supportive treatment: Loperamide can be used for diarrhea, and 5-HT3 antagonists can be used for nausea and vomiting; Maintain a daily urine output of>1.5L to prevent kidney damage.