ivacaftor

What is the most important information I should know about ivacaftor?

Tell your doctor about all your current medicines and any you start or stop using. Many drugs can interact, and some drugs should not be used together.

What is ivacaftor?

Ivacaftor is used to treat cystic fibrosis in adults and children who are at least 4 months old and weigh at least 11 pounds (5 kilograms).

Ivacaftor is for use only in patients with a specific gene mutation related to cystic fibrosis. Before you take ivacaftor, you may need a medical test to make sure you have this gene mutation.

Ivacaftor may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking ivacaftor?

Some medicines can cause unwanted or dangerous effects when used with ivacaftor. Your doctor may change your treatment plan if you also use:

• rifabutin or rifampin;
• St. John's wort; or
• seizure medicine such as carbamazepine, phenobarbital, or phenytoin.

Tell your doctor if you have ever had:

• liver disease; or
• kidney disease.

How should I take ivacaftor?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

To use ivacaftor oral granules: Mix the granules with 1 teaspoon of liquid or soft food such as water, juice, milk, pudding, yogurt, or applesauce. Mix only 1 dose at a time, and use the mixture within 1 hour after mixing. Feed the child a high-fat food just before or just after giving the granule mixture.

Take your doses at regular intervals, 12 hours apart.

Ivacaftor doses are based on age and weight in children. Children from 4 months to 5 years old should take oral granules. Children 6 and older should take tablets.

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

A child using this medicine may need frequent eye exams.

What happens if I miss a dose?

Use the medicine as soon as you can, but skip the missed dose if you are more than 6 hours late for the dose. Do not use two doses at one time.

What happens if I overdose?

What should I avoid while taking ivacaftor?

Grapefruit and Seville oranges may interact with ivacaftor and lead to unwanted side effects. Avoid the use of grapefruit products and orange marmalades.

What are the possible side effects of ivacaftor?

• severe stomach pain;
• vision problems, eye pain;
• low blood sugar --headache, hunger, sweating, irritability, dizziness, nausea, fast heart rate, and feeling anxious or shaky; or
• liver problems --loss of appetite, stomach pain (upper right side), nausea, vomiting, dark urine, jaundice (yellowing of the skin or eyes).

Common side effects may include:

• dizziness;
• rash;
• headache;
• stomach pain, nausea, diarrhea; or
• cold symptoms such as stuffy nose, 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.

What other drugs will affect ivacaftor?

Tell your doctor about all your other medicines, especially:

• an antibiotic --ciprofloxacin, clarithromycin, erythromycin, telithromycin; 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.

Where can I get more information?

Your pharmacist can provide more information about ivacaftor.