Ivacaftor

Ivacaftor is used to treat cystic fibrosis in adults and children who are at least 1 month old and weigh at least 6 pounds (3 kilograms).

Ivacaftor tablet can be used in children aged 6 years and older. Ivacaftor granules can be used in children aged 1 month to under 6 years old.

Your doctor will confirm that you have the specific gene mutation related to cystic fibrosis to be treated with ivacaftor.

Ivacaftor may also be used for other reasons not mentioned in this medication guide.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Take ivacaftor with food that contains fat, such as eggs, whole milk, cheese, yogurt, breast milk, or infant formula. Follow your doctor's instructions carefully.

Swallow the tablet whole and do not crush, chew, or break it.

Mix the ivacaftor granules with 1 teaspoon of soft food such as pureed fruits or vegetables, yogurt, applesauce, water, breast milk, infant formula, milk, or juice. Mix only 1 dose at a time and use within 1 hour after mixing. Feed the child a high-fat food after or before giving the granule mixture.

Take this medicine at evenly spaced intervals every 12 hours.

Doses are based on weight in children. Your child's dose may change if the child gains or loses weight.

You will need frequent blood tests to check your liver function.

Your child may need frequent vision exams.

Store at room temperature away from moisture and heat. Keep the medicine in the original packaging.

Use only as directed. Inform your doctor if you are taking other medicines or have other medical conditions or allergies.

You should not use ivacaftor if you are allergic to it, or if you have or have ever had:

• liver or kidney disease.

It is not known if ivacaftor will harm an unborn baby. Tell your doctor if you are pregnant or planning to become pregnant.

Ask a doctor if it is safe to breastfeed while using ivacaftor.

Get emergency medical help if you have signs of an allergic reaction: hives, trouble breathing, swelling of your face, lips, tongue, or throat.

Ivacaftor may cause serious side effects. Call your doctor right away if you have:

• blurred vision, eye pain or redness, seeing halos around lights;
• low blood sugar--headache, hunger, weakness, sweating, confusion, irritability, dizziness, fast heart rate, or feeling jittery; or
• liver problems--loss of appetite, nausea, vomiting, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Common side effects of ivacaftor may include:

• muscle or joint pain;
• dizziness;
• rash, acne;
• headache;
• mouth pain;
• stomach pain, nausea, diarrhea; or
• cold symptoms such as stuffy nose, sneezing, runny nose, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Take the medicine as soon as you can, with a fatty meal, but skip the missed dose if you are more than 6 hours late for the dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid driving or doing anything dangerous until you know how ivacaftor will affect you. Dizziness or drowsiness can lead to falls, accidents, or serious injuries.

Grapefruit may interact with ivacaftor and cause side effects. Avoid consuming grapefruit products.

Sometimes it is not safe to use certain medicines together. Some drugs can change the amount of other drugs in your blood, which may increase side effects or make the medicines less effective.

Tell your doctor about all your other medicines, especially:

• St. John's wort;
• seizure medicine such as carbamazepine, phenobarbital, or phenytoin;
• an antibiotic--clarithromycin, erythromycin, telithromycin, rifabutin, rifampin; or
• antifungal medicine--fluconazole, itraconazole, ketoconazole, posaconazole, voriconazole.

This list is not complete. Other drugs may affect ivacaftor, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.