What is Iressa (Gefitinib)?
Iressa is an oral medication prescribed to treat lung cancer. It contains the active ingredient gefitinib, which belongs to the class of drugs known as tyrosine kinase inhibitors. Iressa works by slowing or stopping the growth of cancer cells by binding to epidermal growth factor receptor, a protein found on normal cells and densely on cancer cells. Left untreated, this is what permits the uncontrolled proliferation of the tumor cells. Blocking this protein with Iressa therefore reduces cancer growth.
Iressa is supplied as tablets to be taken orally, with or without food, usually once per day. Follow the instructions provided by your doctor carefully. If you have difficulty swallowing the tablet whole, you may dissolve it in 120-240mL of water, stirring for 15 minutes. Drink all of the solution immediately. Fill the cup with another 120-240mL of water and swirl it before drinking it too, to ensure you get the full dose. Do not prepare this mixture ahead of time.
The prescribed dosage is dependent on the severity of your condition, existing medication schedule, lab test results, and how you respond to treatment. Take this medication consistently to achieve the most benefit. Take it at the same time each day to help you remember. Do not take more product or more frequently than instructed by your doctor. This will not improve your condition any faster and may instead cause negative side effects. Do not share this medication with anyone else, even if they have the same condition as you.
Store this medication in a location that will not exceed 25°C. Store away from direct sunlight and moisture. Do not keep in a bathroom. Keep out of reach of children and pets. Do not take expired medication. Dispose of expired or surplus medication responsibly, following the instructions of your healthcare professional. Do not flush medication down the toilet or sink.
Common Side Effects
All medication comes with a risk of side effects. It is important to recognize that your doctor has determined your risk of side effects is outweighed by the potential benefit this medication can provide. Side effects will differ between individuals, and it is possible that you may not experience any side effects at all. Inlyta is commonly associated with the following:
- Appetite loss
- Changes or problems in the finger or toenails
- Sores in the mouth or throat
- Unusual weakness
If you experience any of these symptoms and they concern you, or they worsen or do not resolve on their own, contact your doctor for what to do next.
Diarrhea can lead to dehydration, so it is important that you drink plenty of fluids to compensate. Signs of severe dehydration include dizziness, unusual dry mouth, unusual reduction in urination, and fast heartbeat. Dehydration can lead to kidney problems, so be sure to get medical help if you experience these symptoms.
Severe Side Effects
Occasionally, Iressa can be associated with severe side effects that should be taken seriously. Tell your doctor immediately if you notice any unusual bleeding such as coughing up blood or blood present in the urine, irritation or pain in the eye, or swelling of the ankles or feet.
Gefitinib can be associated with the onset of interstitial lung disease (ILD). Tell your doctor immediately if you experience difficulty breathing, unusual cough or fever.
A severe allergic reaction to this medication is rare, but not unlikely. Seek emergency medical help if you experience symptoms of an allergic reaction, such as severe rash, itching, facial swelling, dizziness, or difficulty breathing.
This is not an exhaustive list of side effects associated with Iressa. If you experience any unusual changes while taking this medication, contact your doctor for what to do next.
Warnings & Precautions
Tell your doctor if you are allergic to any of the ingredients of Iressa before you start taking it. Also tell your doctor if you have a history of severe allergic reactions to other medication.
Ensure your doctor is aware of your complete personal and family medical history, especially of lung disease (e.g. pulmonary fibrosis), kidney disease, eye problems, gastrointestinal ulcers or other problems (e.g. diverticulitis), smoking, or bowel cancer.
Prior to having surgery, ensure all medical personnel involved in your care are aware of all medications you take on a regular basis, including prescription and non-prescription.
This medication can harm an unborn fetus, and therefore people who are pregnant should not handle nor breathe the dust from this medication. If you are pregnant, intend to become pregnant, think you could be pregnant, or do become pregnant, do not take this medication. Fertile people with uterus’s should use reliable methods of birth control while taking this medication.
It is not known whether this medication can pass into breast milk. Breastfeeding is not recommended while taking this medication because of the risk it poses to the nursing infant. Wait at least two weeks after stopping this medication before breastfeeding. Ask your doctor for more information if you are unsure.
Interactions & Contraindications
Two or more medications taken alongside each other can interact with one another, changing how one or more function in the body or lead to unwanted side effects. It is therefore important that drug-drug interactions are minimized. Keep a comprehensive list of all medications you take on a regular basis, including prescription, non-prescription, and herbal supplements. Do not stop, start, or change the dosage of any medication without first consulting your doctor.
Some medications that can have unwanted interactions with Iressa include blood thinners such as aspirin or warfarin, medications that reduce stomach acid (ranitidine, cimetidine, omeprazole), NSAIDs (e.g., ibuprofen), and corticosteroids.
Drugs that induce the receptor that gefitinib acts on increases metabolism and reduces plasma concentration of gefitinib. Thus, dosage should be increased to compensate. Drugs that inhibit the receptor have the opposite effect, and the dosage should be decreased. Monitor adverse reactions when taking inhibitors alongside gefitinib.
Proton pump inhibitors (PPIs), antacids, and other medications that reduce the production of stomach acid can impair the absorption of gefitinib, reducing its function in the body. If you are currently taking PPIs, take gefitinib minimum 12 hours before or 12 hours after the PPI. Antacids or H2 blockers should be taken 6 hours before or after gefitinib.