Adults with a specific type of gastrointestinal stromal tumour (GIST; a type of tumour growing in the wall of the stomach, intestine (bowel), or oesophagus [tube connecting the throat with the stomach]) that has spread to other parts of the body or cannot be removed surgically are treated with avapritinib. Additionally, some forms of mastocytosis are managed with it (a blood disorder in which there are too many mast cells [a certain kind of white blood cell]). Avapritinib belongs to the group of drugs known as kinase inhibitors. It functions by preventing the aberrant protein from signalling the growth of cancer cells. This aids in preventing or reducing the spread of cancer cells.

Avapritinib is available as an oral tablet. On an empty stomach, at least 1 hour before and 2 hours after a meal, it is typically taken once daily. Avapritinib should be taken every day at roughly the same time. Ask your doctor or pharmacist to explain any instructions on your prescription label that you are unsure about following. Avapritinib should only be used as prescribed. Never take it in larger or less amounts or more frequently than directed by your doctor.

Do not take another dose of avapritinib if you vomit after taking it. Continue taking your medication as usual.

Depending on how well the drug works for you and whether you suffer any side effects, your doctor may reduce your avapritinib dose or cease your therapy. Tell your doctor how you are feeling throughout your avapritinib treatment. Without consulting your doctor, do not discontinue taking avapritinib.

For a copy of the manufacturer’s information for the patient, ask your pharmacist or doctor.

Ask your doctor or pharmacist for more details if you believe this drug should be used for something else.

Before taking avapritinib,

• If you have an allergy to avapritinib, any other medications, or any of the ingredients in avapritinib tablets, tell your doctor and pharmacist right away. Request a list of the components from your pharmacist.
• Inform your doctor and pharmacist about any additional prescription and over-the-counter drugs, vitamins, and dietary supplements you are currently taking or intend to take. Include the following information: aprepitant (Emend); certain antifungal drugs as itraconazole (Onmel, Sporanox), fluconazole (Diflucan), or ketoconazole; erythromycin (E.E.S., Erythrocin, others), diltiazem (Cardizem, Tiazac, others), clarithromycin (Biaxin, in Prevpac); certain HIV drugs such efavirenz (Sustiva, in Atripla); indinavir (Crixivan); nelfinavir (Viracept); nevirapine (Viramune); ritonavir; rifabutin (Mycobutin), oxcarbazepine (Trileptal), phenobarbital, phenytoin (Dilantin, Phenytek), pioglitazone (Actos, in Actoplus, Duetact, Oseni), rifampin (Rifadin, Rimactane, in Rifater), and verapamil (Calan). Your physician might need to adjust the dosage of your drugs or keep a close eye on you for side effects. Tell your doctor about all of the drugs you are taking, even any not on this list, since many other drugs may also interact with avapritinib.
• Please let your doctor know if you are taking any herbal supplements, especially St. John’s wort.
• Inform your physician if you have or have ever had liver or kidney problems, low platelet counts (a type of blood cell), or bleeding in your brain. Additionally, let your doctor know if you have ever had a stroke, especially if it occurred within the previous year.
• Inform your doctor if you are expecting, intend to get pregnant, or intend to father a child. You must perform a pregnancy test before beginning therapy if you are a female, and you must use birth control to avoid getting pregnant while receiving treatment and for six weeks after your last dose. If you’re a man, you should use birth control while you’re receiving treatment and for six weeks following your last dose. Consult your physician about birth control options you can take while undergoing therapy. Call your doctor right away if you or your partner become pregnant while taking avapritinib. The foetus could be harmed by avapritinib.
• Inform your doctor if you are nursing a baby. While using avapritinib and for at least two weeks following your last dose, you shouldn’t breastfeed.
• You should be aware that this medicine may lower both male and female fertility. Describe the dangers of taking avapritinib to your doctor.
• If you miss a dosage, take it as soon as you recall. Skip the missed dosage and continue with your regular dosing regimen if the next dose is due in less than 8 hours. To make up for a missing dose, do not take a second one.

If you plan to consume grapefruits or grapefruit juice while taking this medication, consult your doctor.

If you miss a dosage, take it as soon as you recall. Skip the missed dosage and continue with your regular dosing regimen if the next dose is due in less than 8 hours. To make up for a missing dose, do not take a second one.

There may be negative effects from avapritinib. If any of these symptoms are severe or do not go away, let your doctor know right once:

• Abdominal pain
• Vomiting
• Nausea
• Diarrhea
• Heartburn
• Headache
• Tiredness
• Having trouble falling or staying asleep
• Hair fall
• Changing hair colours
• Loss of weight
• Bleak eyes
• Changing tastes

Some adverse effects can be very harmful. Avapritinib should be stopped immediately if you have any of the following symptoms, and you should also seek emergency medical attention if necessary:

• Face, eye, mouth, or throat swelling
• Hand, ankle, or foot swelling
• Vomiting blood, coffee grounds-looking stuff, or red or tarry black stools
• Excessive fatigue, drowsiness, vision issues, nausea, vomiting, or weakness on one side of your body
• Hallucinations, changes in attitude or behaviour, forgetfulness, confusion, tiredness, dizziness, difficulty sleeping, difficulty speaking, and so on
• Rash
• Breathing difficulty
• Fever or other infection-related symptoms

Other negative effects of avapritinib are possible. If you experience any strange issues while taking this medicine, contact your doctor right away.

You or your doctor can submit a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting programme online or by phone if you have a serious side event (1-800-332-1088).

Keep this medication tightly closed in the original container and out of the reach of children. Store it away from light, excessive heat, and moisture at room temperature (not in the bathroom).

As many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and are simple for young children to open, it is crucial to keep all medications out of sight and out of reach of children. Always lock safety caps and promptly stash medication up and away from young children where it is out of their sight and reach to prevent poisoning. http://www.upandaway.org

Unused prescriptions must be disposed of carefully to prevent pets, kids, and other people from ingesting them. You should not, however, dispose of this medication in the toilet. Instead, utilising a medicine take-back programme is the easiest approach to get rid of your medication. To find out about take-back programmes in your area, speak with your pharmacist or the garbage/recycling department in your city. If you do not have access to a take-back programme, see the FDA’s Safe Disposal of Medicines website at http://goo.gl/c4Rm4p for additional information.

Call the poison control hotline at 1-800-222-1222 in the event of an overdose. Additionally, information can be found online at https://www.poisonhelp.org/help. Call 911 right once if the person has collapsed, experienced a seizure, is having difficulty breathing, or cannot be roused.

Keep all of your appointments with your physician and the lab. Before you start your therapy, your doctor will run a lab test to determine whether avapritinib can treat your cancer. To monitor how your body is responding to avapritinib, your doctor may request specific lab tests.

No one else should take your medication. Any queries you may have regarding medication refills should be directed to your pharmacist.

You should keep a written record of every medication you take, including any over-the-counter (OTC) items, prescription drugs, and dietary supplements like vitamins and minerals. This list should be brought with you whenever you see a doctor or are admitted to the hospital. You should always have this information with you in case of emergencies.