Ivacaftor

Pronunciation: pronunciation varies by local usage.

Generic name: ivacaftor
Brand names: KALYDECO
Drug class: CFTR potentiator
Form: Tablet, film coated; granule
Route: Oral
Legal status: Prescription-only medicine

Availability and supply rules vary by country

Trade names by country: United States · Canada

What ivacaftor is and how it works

Ivacaftor is a CFTR (cystic fibrosis transmembrane conductance regulator) potentiator used to treat cystic fibrosis in patients who have at least one mutation in the CFTR gene that is responsive to ivacaftor. (1)

It is approved for patients aged 1 month and older with responsive mutations, with weight-based dosing for children under 6 years. It must be taken with fat-containing food and requires regular monitoring for liver function and neuropsychiatric symptoms, plus regular eye examinations in pediatric patients.

Mechanism of action: how ivacaftor works

Ivacaftor is classified as a CFTR potentiator. (1)

What ivacaftor is used for

Cystic fibrosis

Ivacaftor is indicated for the treatment of cystic fibrosis in patients aged 1 month and older who have at least one CFTR gene mutation responsive to ivacaftor based on clinical and/or in vitro assay data. The specific mutations and age-based dosing are determined by the prescribing specialist. (1)

Before taking ivacaftor

Do not take / not appropriate for

No contraindications are listed in the reviewed US label. The label states that treatment should be discontinued if a serious hypersensitivity reaction (such as anaphylaxis) occurs. If you have had a serious hypersensitivity reaction to ivacaftor, seek emergency medical attention promptly and tell the clinician treating you; discontinuation will be carried out and directed by that clinician. (all products) (1)

Tell your clinician about

Any history of liver disease or abnormal liver tests.
Any eye problems, cataracts, or planned eye exams, especially in children.
Any mental health symptoms, such as anxiety, depression, or suicidal thoughts.
Symptoms of increased pressure in the brain (unusual headache, visual disturbances).
Pregnancy, plans for pregnancy, or breastfeeding.
All medicines and supplements you take, including over-the-counter, herbal, and grapefruit juice.

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How to take ivacaftor

Take KALYDECO exactly as prescribed by your specialist, usually every 12 hours.
Take each dose with a meal or snack that contains fat, such as those recommended (eggs, butter, peanut butter, cheese pizza, whole-milk dairy products).
Follow the instructions in your product's package leaflet or ask your pharmacist.
Do not change the dose, timing, or formulation without your clinician's approval.
Continuing or stopping KALYDECO is a decision for your CF team; let them know before you consider stopping, and if you have concerns about your treatment, discuss them with your CF team rather than changing or stopping treatment on your own.

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Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)

Missed dose

If you miss a dose, contact your prescriber or pharmacist for instructions rather than deciding on your own.

Overdose

If you think you or someone else may have taken too much KALYDECO, contact emergency services, a poison control center, or a clinician promptly for urgent advice.

Side effects

The most common side effects in clinical trials were headache, oropharyngeal pain, upper respiratory tract infection, nasal congestion, abdominal pain, nasopharyngitis, diarrhoea, nausea, rash, and dizziness. Serious side effects can also occur: some (like a severe allergic reaction) need emergency care right away, while others (like signs of liver or eye problems) need prompt contact with your care team — see below for which is which.

Headache

What to notice: Headache; frequency 24% in studies.

What to do: If bothersome or persistent, discuss with your CF care team. (1)

Upper respiratory symptoms

What to notice: Sore throat (22%), nasal congestion (20%), upper respiratory tract infection (22%), nasopharyngitis (15%).

What to do: These are common; inform your team if severe or not improving. (1)

Gastrointestinal effects

What to notice: Abdominal pain (16%), diarrhoea (13%), nausea (12%).

What to do: Notify your prescriber if persistent or severe. (1)

Rash

What to notice: Skin rash (13%); can vary in appearance and severity.

What to do: Report any new rash to your clinician, especially if associated with other allergy symptoms. (1)

Dizziness

What to notice: Feeling lightheaded or unsteady (9%).

What to do: Inform your team if troublesome. (1)

Liver injury (transaminase elevation)

What to notice: Liver function (ALT/AST) is monitored by scheduled blood tests.

What to do: Attend all scheduled liver function blood tests. Contact your clinic if you notice anything you are concerned about; do not skip scheduled liver function tests. (1)

Cataracts

What to notice: Non-congenital lens opacities/cataracts have been reported in pediatric patients treated with KALYDECO, which is why pediatric patients need baseline and follow-up eye exams.

What to do: Attend recommended baseline and follow-up ophthalmological check-ups and report anything you are concerned about to your clinician. (1)

Neuropsychiatric symptoms

What to notice: Symptoms of anxiety, depression, and suicidal ideation have been reported.

What to do: Inform your CF team promptly about any new or worsening symptoms of anxiety, depression, or suicidal thoughts; they will assess whether further treatment changes are needed. (1)

Hypersensitivity reaction

What to notice: Postmarketing reports include anaphylaxis.

What to do: Seek emergency medical attention for any signs of a severe allergic reaction. For a milder reaction you are unsure about, consult your prescriber. (1)

Intracranial hypertension

What to notice: Unusual headache or visual disturbance.

What to do: Contact your prescriber promptly if you notice an unusual headache or visual disturbance; treatment may need to be interrupted, as directed by your clinician. (1)

Serious warnings

Severe hypersensitivity (anaphylaxis) — emergency

Symptoms: Postmarketing reports include anaphylaxis.

Action: Seek emergency medical attention immediately. The label states treatment should be discontinued if a serious hypersensitivity reaction occurs; the clinician who treats the reaction will carry this out. (1)

Interactions

Medicine or test	Effect	Action
Strong or moderate CYP3A inhibitors (e.g., ketoconazole, fluconazole, grapefruit juice)	These can significantly increase ivacaftor levels, raising the risk of side effects.	In patients 6 months and older, your prescriber will reduce the KALYDECO dose to once daily. Co-administration is not recommended in infants younger than 6 months. Avoid grapefruit juice. (1)
Strong CYP3A inducers (e.g., rifampin, St. John's wort)	These can greatly reduce ivacaftor levels, making it less effective.	Co-administration is not recommended. Your CF team will decide how to manage this; do not start or stop any medicine without discussing it with them first. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Children and adolescents

Dosing is age- and weight-specific. Children younger than 6 years use oral granules; those 6 years and older take the tablet. Pediatric patients require regular eye examinations for cataract development. The exact dosing must be determined by a CF specialist using the current label. (1)

Pregnancy and breastfeeding

Limited human data are available. Animal studies showed no teratogenicity at high exposures. The benefits and risks should be discussed with a healthcare provider. Ivacaftor is excreted into rat milk; the presence in human milk is unknown. Weigh the benefits of breastfeeding against the mother's clinical need and potential infant risks. (1)

Hepatic impairment

Mild impairment: no dose adjustment needed. Moderate impairment: reduce dosing to once daily. Severe impairment: use with caution at a reduced dose/frequency, weighing benefits against risks. Liver function must be monitored closely. (1)

Monitoring

Before starting

Confirm the presence of a CFTR gene mutation responsive to ivacaftor via approved testing.
Perform baseline liver function tests (ALT, AST).
Conduct a baseline ophthalmological examination in pediatric patients.
Your clinician may also consider your neuropsychiatric history, current medicines (for interactions), and pregnancy status when starting treatment — the reviewed sources do not specify this as a formal mandatory pre-treatment checklist item.

During treatment

Monitor liver function tests every 3 months for the first year, then annually thereafter.
Your clinician will interrupt dosing if ALT or AST exceeds 5 times the upper limit of normal, and will decide the criteria for restarting treatment.
Perform regular eye exams in pediatric patients for cataract development.
Monitor for signs of intracranial hypertension, neuropsychiatric symptoms, and hypersensitivity.
Your clinician may reassess drug interactions if other medicines are added or stopped, though this was not stated as a formal requirement in the sources reviewed.

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Storage

Please refer to the manufacturer's product label and packaging for detailed handling and storage requirements.

Professional information

Clinician-facing context only. Use the current local indication, dosing table, and safety information from the full prescribing information.

United States (only the US label was reviewed; no UK/EU, Canadian, Australian, or other non-US label was reviewed)

Indication: Cystic fibrosis with responsive CFTR mutation

Dose summary: Adults and pediatric patients ≥6 years: 150 mg orally every 12 hours with fat-containing food. Pediatric patients 1 month to <6 years: weight-based oral granules every 12 hours (doses range from 5.8 mg to 75 mg per dose, per the detailed weight band table in the label). Dose adjustments required for moderate hepatic impairment (reduce to once daily) and with strong/moderate CYP3A inhibitors (reduce to once daily in patients ≥6 months; not recommended in infants <6 months). Avoid strong CYP3A inducers.

Renal context: No specific renal dosing information was reviewed; refer to local product information. (1)

Mechanism of action

Hepatic guidance

Hepatic impairment: mild – no adjustment; moderate – reduce to once daily; severe – use with caution and reduced frequency. Monitor liver function regularly.

Overdose note

Route urgent concerns to emergency services, a poison control center, or the treating clinician rather than presenting an unverified management protocol. (1)

Frequently asked questions

Do I have to take KALYDECO with food?

Yes, it must be taken with a meal or snack containing fat to ensure proper absorption. Examples include eggs, butter, peanut butter, cheese pizza, or whole-milk dairy products. (1)

Can I drink grapefruit juice while on KALYDECO?

No, grapefruit juice can raise ivacaftor levels and should be avoided. It contains substances that inhibit the enzyme that breaks down ivacaftor. (1)

What tests do I need while on KALYDECO?

Regular blood tests to check liver function are needed before starting, every 3 months for the first year, then annually. Children also need regular eye exams to check for cataracts. (1)

Can KALYDECO cure CF?

It is a treatment indicated for cystic fibrosis in patients with a CFTR gene mutation responsive to ivacaftor; it is classified as a CFTR potentiator. Ask your CF team how it fits into your overall treatment. (1)

What is the mechanism of action of ivacaftor?

Ivacaftor is classified as a CFTR potentiator. (1)

What is the generic name of Ivacaftor?

The generic name is ivacaftor. It is sold under brand names including KALYDECO. (1)

What class of drug is ivacaftor?

Ivacaftor is classed as: CFTR potentiator. (1)

References

KALYDECO — ivacaftor tablet, film coated; KALYDECO — ivacaftor granuleU.S. National Library of Medicine (DailyMed) / U.S. Food and Drug Administration · United States · accessed 2026-08-05 · source 1
TRIKAFTA (ELEXACAFTOR, TEZACAFTOR, AND IVACAFTOR) KIT [VERTEX PHARMACEUTICALS INCORPORATED] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 2
Ivacaftor — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 3
Kalydeco — FDA approval record (Drugs@FDA NDA203188)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 4
ivacaftor — RxNorm normalized drug concept (RXCUI 1243041)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 5

Brand names by country

Single-ingredient ivacaftor names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

Kalydeco13.4 mg, 25 mg, 150 mg, 5.8 mg, 75 mg, 50 mg · vertex pharmaceuticals incorporated

Canada

KALYDECO

View brands in additional countries.