Gefitinib
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DRUG STATUS
Approvals
US(FDA), UK(BNF)
Essential Medicine
YES
Teratogenicity
Definite
Pharmaceutical Class
Kinase Inhibitor
Gefitinib
Know More About This Medicine -
Click HereSummary
Gefitinib is used to treat locally advanced or metastatic non-small cell lung cancer (NSCLC) that has certain types of gene mutations known as EGFR mutations. It is primarily prescribed for patients who have not received prior chemotherapy.
Gefitinib is an EGFR tyrosine kinase inhibitor. It works by blocking signals for cancer cell growth, specifically targeting mutated EGFR receptors, preventing them from sending signals that cause uncontrolled cell division. This leads to tumor shrinkage and slowed progression of NSCLC.
The standard dose of Gefitinib for adults is 250 mg once daily. It is taken orally, usually as a single tablet at the same time each day.
Common side effects of Gefitinib include diarrhea, skin rash, nausea, vomiting, and loss of appetite. Serious but less common risks include liver toxicity, lung inflammation, and severe diarrhea leading to dehydration.
Gefitinib should not be taken by people without EGFR mutations, pregnant or breastfeeding women, people with severe liver or kidney disease, or those with a history of interstitial lung disease. Patients allergic to Gefitinib or any of its ingredients should avoid this medicine.
Indications and Purpose
What is Gefitinib used for?
Gefitinib is used for the treatment of non-small cell lung cancer (NSCLC) that is locally advanced or metastatic and has EGFR gene mutations. It is prescribed mainly for patients who have not received prior chemotherapy. This medication is most effective in patients with specific genetic mutations confirmed through EGFR testing. It is not effective in cancers that do not have these mutations.
How does Gefitinib work?
Gefitinib is an EGFR tyrosine kinase inhibitor (TKI) that blocks signals for cancer cell growth. It specifically targets mutated EGFR receptors, preventing them from sending signals that cause uncontrolled cell division. This leads to tumor shrinkage and slowed progression of NSCLC. It is most effective in tumors with EGFR mutations, as normal EGFR cells are less affected.
Is Gefitinib effective?
Clinical studies have shown that gefitinib is highly effective in NSCLC patients with EGFR mutations, improving survival rates and quality of life. Studies indicate that progression-free survival (PFS) is longer compared to standard chemotherapy. However, it does not work well for tumors without EGFR mutations. Research shows that patients with mutations exon 19 deletion or exon 21 L858R benefit the most from this treatment.
How does one know if Gefitinib is working?
Doctors monitor the effectiveness of gefitinib using CT scans, MRIs, or PET scans to check for tumor shrinkage. Patients may also notice reduced cancer symptoms like less coughing, improved breathing, and less fatigue. Blood tests and biomarker monitoring may also be used. If the tumor continues to grow, doctors may recommend alternative treatments.
Directions for Use
What is the usual dose of Gefitinib?
The standard dose of gefitinib for adults is 250 mg once daily. It is usually taken as a single tablet at the same time each day. It is not commonly used in children, as its safety and efficacy in pediatric patients are not well established. If severe side effects occur, the dose may be adjusted or treatment may be paused, as per the doctor's advice.
How do I take Gefitinib?
Gefitinib should be taken once daily, with or without food. The tablet should be swallowed whole with water. If swallowing is difficult, it can be dispersed in a glass of water and consumed immediately. Avoid grapefruit and grapefruit juice, as they can interfere with the drug’s absorption. Also, St. John’s Wort should be avoided, as it may reduce the effectiveness of gefitinib.
For how long do I take Gefitinib?
Gefitinib is taken as long as it remains effective and the side effects are manageable. Patients may continue treatment for months or years if their cancer does not progress. Regular monitoring with scans and medical tests is required to check whether the medication is working and if any side effects are developing. If the cancer progresses, alternative treatments may be considered.
How long does it take for Gefitinib to start working?
Gefitinib starts working within a few weeks, but noticeable improvements are usually seen after several weeks to months of treatment. Tumor shrinkage or symptom relief may take one to three months. Regular imaging tests like CT scans or MRIs are used to monitor progress. Some patients feel better within the first month, while others take longer to respond.
How should I store Gefitinib?
Store gefitinib at room temperature (15-30°C) in a dry place, away from direct sunlight and moisture. Keep it out of reach of children and do not store it in the bathroom. Do not use expired tablets.
Warnings and Precautions
Who should avoid taking Gefitinib?
Gefitinib should not be taken by people who do not have EGFR mutations, as it will not be effective. It is also not recommended for pregnant or breastfeeding women, people with severe liver or kidney disease, or those with a history of interstitial lung disease. Patients allergic to gefitinib or any of its ingredients should avoid this medicine.
Can I take Gefitinib with other prescription drugs?
Gefitinib interacts with certain antibiotics, antifungals, and anticonvulsants. Drugs like rifampicin, phenytoin, and carbamazepine can lower its effectiveness. Proton pump inhibitors (PPIs) like omeprazole can reduce absorption. Patients should inform their doctor about all medications they are taking to prevent dangerous interactions.
Can I take Gefitinib with vitamins or supplements?
Some vitamins and supplements may interfere with gefitinib. Calcium and magnesium supplements should be taken with caution, as they can alter stomach acidity, affecting drug absorption. Avoid St. John’s Wort, as it can decrease gefitinib’s effectiveness. Always consult a doctor before taking herbal supplements or over-the-counter vitamins while on gefitinib.
Can Gefitinib be taken safely while pregnant?
Gefitinib is not safe during pregnancy, as it can harm the developing fetus. Animal studies suggest that it may cause birth defects and miscarriage. Women of childbearing age should use effective contraception while taking this medication and for at least two weeks after stopping it. If pregnancy occurs, the doctor should be informed immediately.
Can Gefitinib be taken safely while breastfeeding?
Gefitinib is not recommended while breastfeeding because it can pass into breast milk and harm the infant. Women taking gefitinib should avoid breastfeeding during treatment and for at least two weeks after stopping the medication.
Is Gefitinib safe for the elderly?
Gefitinib can be used in elderly patients, but they may be more prone to side effects like diarrhea, liver issues, and skin rashes. Regular monitoring of liver and kidney function is recommended. Dose adjustments may be needed based on tolerance and side effects.
Is it safe to exercise while taking Gefitinib?
Yes, light to moderate exercise is generally safe and can help maintain strength and reduce fatigue. However, strenuous activity should be avoided if patients experience fatigue, dizziness, or weakness from gefitinib. Walking, yoga, and light stretching are usually well-tolerated. If side effects make exercise difficult, consulting a doctor about adjusting activity levels is recommended.
Is it safe to drink alcohol while taking Gefitinib?
Drinking alcohol while on gefitinib is not recommended, as alcohol can worsen side effects like liver toxicity, nausea, and fatigue. Even moderate alcohol consumption may put extra stress on the liver, which is already processing the drug. If patients choose to drink occasionally, they should consult their doctor and limit intake to avoid complications.
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