An Overview of Ivacaftor

Ivacaftor is a prescription drug used to aid in the treatment of cystic fibrosis in patients that have a specific gene mutation. The drug was developed by Vertex Pharmaceuticals, an American Boston-based company, in partnership with the Cystic Fibrosis Foundation. It is the first drug targeted toward cystic fibrosis patients that treats the causes of cystic fibrosis as opposed to the symptoms of it.

Recommended foods to take with ivacaftor
Verywell/Nusha Ashjaee

What Is Cystic Fibrosis?

Cystic fibrosis is a genetic disorder that affects approximately 30,000 Americans and 70,000 people worldwide. There are roughly 1,000 new cases of cystic fibrosis diagnosed each year, with 75 percent of those diagnoses happening to those affected before they reach two years of age. It is caused by a genetic defect in the cystic fibrosis transmembrane receptor (CFTR) gene. This gene is responsible for the creations of sweat, digestive fluids, and mucus.

If the CFTR gene is defective, it can cause accumulation of mucus in the lungs and prevent digestive enzymes—substances secreted by our bodies to help us digest food—to block the intestines.

This buildup leads to a persistent and dangerous cough, wheezing and breathlessness, lung infections, severe constipation, and poor weight gain and growth.

In order to inherit cystic fibrosis, a person has to have two copies of the defective CFTR gene, one from each parent. Someone can have one copy of a defective CFTR gene (which makes him/her a carrier), but not have the disease. If two people who are carriers have a child, there is a 25 percent chance the child will have cystic fibrosis. If one parent has cystic fibrosis and the other is a carrier, there is a 50 percent chance the child will have cystic fibrosis.

One in 31 Americans is a carrier of a defective CFTR gene, and often there are no symptoms associated with being a carrier. The only way to determine your carrier status is through genetic testing, which is recommended by The American College of Obstetricians and Gynecologists (ACOG) for all couples thinking about getting pregnant or who are currently pregnant.

How Ivacaftor Works

Ivacaftor treats a specific CFTR gene defect, the G551D mutation, which accounts of approximately 4 to 5 percent of cystic fibrosis diagnosis. Approved by the Food and Drug Administration (FDA) in 2012, it treats the gene defect as opposed to the symptoms associated with cystic fibrosis by increasing the ion function of this protein gene in the body. In turn, this helps to decrease the build-up of mucus in the lungs.

This leads to easier breathing and less airway obstruction, in addition to helping alleviate other symptoms associated with cystic fibrosis, such as lung infections. It’s important to remember that ivacaftor treats cystic fibrosis, but it doesn’t cure it.

Even if a patient starts to feel better while taking the prescription, it’s extremely important to keep taking it as prescribed unless discussed differently with your doctor. The usual dosage for ivacaftor is by mouth twice a day, 12 hours apart.

Other Medications

People taking the antibiotics rifampin, rifabutin, or seizure medications such as phenobarbital, carbamazepine, or phenytoin should not take ivacaftor. The herb St. John’s Wort is also discouraged when taking ivacaftor because of harmful interactions and decreased effectiveness of the drug.

Any medication you are currently taking should be discussed with your doctor beforehand, as the interactions between drugs could result in serious and life-threatening side effects.

Ivacaftor and Preexisting Medical Conditions

If you have one or more of the below conditions, it’s important to talk to your doctor before being prescribed ivacaftor:

  • liver or kidney problems
  • pregnant or planning to become pregnant
  • breastfeeding or planning to breastfeed
  • taking medications such as anti-fungal medications or any antibiotics

Ivacaftor and Diet

If you drink grapefruit juice or eat grapefruit or Seville oranges it’s recommended that you remove these from your diet when taking ivacaftor. These citruses may increase the amount of medicine in your blood as well as the severity of side effect associated with the drug.

When taking ivacaftor, it’s recommended to combine it with high-fat foods, which can help the body absorb the drug better and aid in weight gain, as many patients with cystic fibrosis have a difficult time gaining weight. Some good sources of fat include:

  • Eggs
  • Avocado
  • Oatmeal
  • Whole milk
  • Whole yogurt
  • Multigrain toast
  • Cheese
  • Turkey burger
  • Hummus
  • Peanut butter

Side Effects

The most common side effects with ivacaftor include:

  • Headache
  • Stomach pain
  • Diarrhea
  • Rash
  • Nausea
  • Dizziness
  • Nasal and sinus congestion
  • Runny nose
  • Sore throat

Ivacaftor and Children

Prescribing children ivacaftor is generally safe and effective when prescribed between the ages of one and two years old. When prescribed and taken for 24 weeks, patients saw a reduction in sweat concentration and improvements in pancreatic function.

Studies are now starting to examine the effects of the drug on children younger than one year, as early intervention is crucial to managing cystic fibrosis symptoms long-term.

Precision Medicine

Precision medicine looks at individual factors of a patient’s disease and the treatments that will benefit them the most based on their unique case. Since its FDA approval in 2012 for the G551D variant, the drug has been approved for 37 additional gene mutations, making treatment possible for 14 percent of cystic fibrosis diagnosis.

This type of precision medicine has helped reduce rates of pulmonary morbidity, increased patient weight gain and quality of life, and decreased the amount of cystic fibrosis-related hospital admissions. Ivacaftor is a prime example for the precision medicine community as a drug targeted for a specific set of people that can later be implemented to a larger population.


One of the biggest issues with ivacaftor, aside from its very specific and narrow group of cases that it can help, is the cost of the drug. Though success rates are high among the patients approved to use the drug, treatment is expensive, costing over $300,000 per year.

While many private health insurances will cover the drug, those without coverage who could benefit from it are likely unable to afford it, especially considering those on ivacaftor typically have to take the drug for the rest of their lives, resulting in millions of dollars for one patient’s treatment.

This is an important factor to take into consideration if you or a loved one has cystic fibrosis—be sure to discuss these and any other concerns with your doctor if you think ivacaftor may be a viable treatment option for you. Make sure you consult with your health insurance provider, if you have one, to see if they cover this prescription medication.

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