ivacaftor at a glance
Medicine class
CFTR potentiator
Eligibility
Requires confirmation of a responsive CFTR mutation
Food
Take with fat-containing food; avoid grapefruit
Monitoring
Liver blood tests are required; children also need eye examinations
What is ivacaftor used for?
Licensed uses represented by the selected products include:
Monotherapy for cystic fibrosis with an eligible gating mutation or R117H mutation, subject to age and weight criteria.
Use with tezacaftor/ivacaftor for eligible people with F508del-related cystic fibrosis and a licensed second mutation.
Use with ivacaftor/tezacaftor/elexacaftor for eligible people with at least one F508del mutation.
How does ivacaftor work?
CFTR is a channel that moves chloride across cell surfaces. In responsive mutations, ivacaftor helps the channel stay open, improving chloride transport and the abnormal salt-and-water balance that produces thick secretions.
ivacaftor preparations and strengths
Sachet
Route: Oral
Strengths: 13.4 mg, 25 mg, 50 mg, 59.5 mg, 75 mg
How to take ivacaftor
Follow the cystic fibrosis team’s instructions and take ivacaftor with fat-containing food. Swallow tablets whole. Mix the entire granule sachet with a small amount of suitable soft food or liquid at room temperature or cooler, then consume promptly. Avoid grapefruit.
Use each granule sachet once only.
Do not change formulations without specialist instructions.
Ask the cystic fibrosis team before starting prescribed, non-prescribed or herbal products.
ivacaftor side effects
Common or expected effects
- Headache
- Sore throat or upper respiratory infection symptoms
- Blocked or runny nose
- Abdominal pain or diarrhoea
- Dizziness
- Rash
- Raised liver enzymes
Get urgent medical advice
- Symptoms of liver injury, including jaundice, dark urine, upper-right abdominal pain, loss of appetite, nausea or vomiting
- Severe or persistent abdominal pain
- A significant rash, particularly during combination treatment
ivacaftor in pregnancy
Pregnancy data are limited. The SmPC advises precautionary avoidance, while UK pregnancy information notes no current indication of fetal harm and emphasises the importance of cystic fibrosis control. Discuss treatment with the cystic fibrosis and maternity teams; do not stop without specialist advice.
ivacaftor while breastfeeding
It is unknown whether ivacaftor or its metabolites enter human breast milk, so risk to an infant cannot be excluded. Specialist teams should weigh the benefits of breastfeeding against the benefits of treatment before either changes.
ivacaftor interactions
Important interactions mainly involve CYP3A metabolism and medicines with narrow therapeutic ranges.
Rifampicin, rifabutin, carbamazepine, phenytoin, phenobarbital and St John’s wort
Strong CYP3A induction can greatly reduce ivacaftor exposure and effectiveness; combined use is not recommended.
Azole antifungals, clarithromycin and other strong CYP3A inhibitors
These can substantially increase ivacaftor exposure and require specialist treatment review.
Common questions about ivacaftor
Answers are fully visible for fast scanning and source review.
Why is genetic testing needed?
Licensed uses are limited to defined CFTR mutations and combinations, so genotype confirmation determines eligibility.
Why are liver blood tests needed?
Ivacaftor-containing treatments can raise liver enzymes and have rarely been associated with serious liver injury.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.