What are the precautions for using pemetinib? What should I pay special attention to before and after taking medicine?

1. Precautions before taking medicine

Before using pemigatinib (Pemigatinib), patients should undergo a series of tests to ensure the safety and effectiveness of the drug. The drug is a selective fibroblast growth factor receptor (FGFR) inhibitor, mainly used to treat patients with cholangiocarcinoma carrying FGFR2 gene fusion or rearrangement. Therefore, genetic testing is required before taking the drug to confirm whether the patient's tumor has FGFR2 mutations, otherwise the drug may be ineffective. In addition, patients should undergo liver and kidney function assessment, electrolyte level testing, and eye examination to reduce the risk of adverse reactions that may be caused by the drug.

2. Precautions during medication

1.Follow standard dosage and timing

The recommended dose of pemetinib is usually 13.5 mg once a day, taken continuously for 14 days and then stopped for 7 days, forming a treatment cycle of 21 days. Patients should strictly follow the doctor's instructions and do not increase or decrease the dosage or change the medication time at will. If you miss a dose and it does not exceed 4 hours, you should take it immediately; if it exceeds 4 hours, skip the daily dose and do not double the dose to avoid increasing the risk of side effects.

2.Monitor electrolyte levels

Taking pemetinib may cause hyperphosphatemia, so patients need to regularly monitor blood phosphate levels during treatment and adjust their diet or use phosphate-lowering drugs as needed. If blood phosphorus levels are too high, your doctor may recommend reducing your intake of high-phosphorus foods, such as dairy products, nuts, and red meat.

3.Eye examination

Pemetinib may cause retinopathy or other adverse ocular effects, so patients should receive regular eye examinations before and during treatment. If you experience blurred vision, eye pain, or other visual abnormalities, seek medical attention immediately. Additionally, using artificial tears or eye moisturizers may help relieve eye discomfort.

4.Avoid taking it with certain drugs

Pemetinib is mainly metabolized by the CYP3A4 enzyme of the liver, so patients should avoid taking strong CYP3A4 inhibitors (such as clarithromycin, ketoconazole, etc.) or strong inducers (such as rifampicin, St. John's wort, etc.) at the same time, so as not to affect drug metabolism, thereby affecting efficacy or increasing toxicity. Before taking medicine, you should inform your doctor about all the medicines you are taking, including Chinese herbal medicines and health supplements, to ensure safety.

3. Precautions after taking medicine

1.Monitor adverse reactions

Pemetinib may cause a variety of side effects, including fatigue, loss of appetite, diarrhea, mouth ulcers, etc. Most side effects are mild to moderate, but if you experience severe diarrhea, persistent nausea and vomiting, severe skin reactions, or abnormal liver function, you should seek medical attention promptly. In addition, hyperphosphatemia may further cause calcium and phosphorus metabolism disorders and even cause vascular calcification. Therefore, patients need to regularly review blood phosphorus and calcium levels and follow doctor's recommendations for corresponding treatment.

2.Pay attention to dietary adjustments

While taking pemetinib, patients should avoid high-phosphorus foods, such as dairy products, legumes, nuts, and organ meats, to reduce the risk of hyperphosphatemia. At the same time, maintaining adequate fluid intake and avoiding dehydration can help reduce the risk of gastrointestinal discomfort and kidney damage.

3.Prudently plan pregnancy and breastfeeding

Pemetinib may have adverse effects on the fetus, so women of childbearing potential should use effective contraceptive measures during treatment and for a period of time after discontinuation of the drug. In addition, male patients should also take contraceptive measures during the medication and within 1 week after stopping the medication to prevent the medication from affecting their spouse or fetus. Since the drug may be excreted in breast milk, nursing women should discontinue breastfeeding during treatment to avoid potential effects on the infant.

4. Long-term management and follow-up

Since pemetinib is a targeted therapy, long-term use may lead to drug resistance, so patients should be reviewed regularly to monitor changes in their condition. If signs of resistance appear, doctors may adjust the treatment plan. In addition, patients should maintain a healthy lifestyle during the medication period, including a balanced diet, moderate exercise, and good sleep habits to enhance body tolerance and improve treatment effects.

In general, pemetinib has good efficacy in treating patients with cholangiocarcinoma with FGFR2 gene mutations, but it is necessary to strictly follow medical instructions during use and closely monitor blood phosphorus levels, eye health and other possible side effects. At the same time, reasonable adjustments to diet, avoiding drug interactions, and regular review can help patients receive treatment more safely and effectively.