Ivacaftor: uses, dosing, side effects & brands
Ivacaftor is a cystic fibrosis transmembrane conductance regulator potentiator sold in the U.S. under 2 brand and generic names, for cystic fibrosis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Cystic Fibrosis Transmembrane Conductance Regulator Potentiator
- Treats (across its forms)
- Cystic Fibrosis
- Available as
- Powder · Tablet
- Sold as
- 2 products — Ivacaftor and Kalydeco
- Prescription?
- Prescription only
- Generic available?
- Yes
How ivacaftor is dosed
From the FDA label for Kalydeco (application NDA207925). Other ivacaftor products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Age Weight Dosage Administration 1 month to less than 2 months 3 kg or greater One 5.8 mg packet every 12 hours Mixed with one teaspoon (5 mL) of soft food or liquid and administered orally with fat-containing food 2 months to less than 4 months 3 kg or greater One 13.4 mg packet every 12 hours 4 months to less than 6 months 5 kg or greater One 25 mg packet every 12 hours 6 months to less than 6 years 5 kg to less than 7 kg One 25 mg packet every 12 hours 7 kg to less than 14 kg One 50 mg packet every 12 hours 14 kg or greater One 75 mg packet every 12 hours 6 years and older - One 150 mg tablet every 12 hours Taken orally with fat-containing food See full prescribing information for the recommended dosage in patients aged 6 months and older with moderate or severe hepatic impairment. ( 2.3 , 8.6 ) See full prescribing information for dosage modifications due to drug interactions with KALYDECO. ( 2.4 , 7.1 ) Not recommended in pediatric patients less than 1 month of age. ( 2.2 , 8.4 ) Not recommended in patients 1 month to less than 6 months of age with any level of hepatic impairment and/or taking concomitant moderate or strong CYP3A inhibitors. ( 2.3 , 2.4 , 8.6 ) 2.1 Recommended Dosage in Adults and Pediatric Patients Aged 6 Years and Older The recommended dosage of KALYDECO for adults and pediatric patients aged 6 years and older is 150 mg orally every 12 hours (300 mg…
Ivacaftor side effects
The following adverse reactions are discussed in greater detail in other sections of the labeling: Transaminase Elevations [ see Warnings and Precautions (5.1) ] Hypersensitivity Reactions, Including Anaphylaxis [see Warnings and Precautions (5.2) ] Intracranial Hypertension [see Warnings and Precautions (5.3) ] Neuropsychiatric Events, Including Suicidal Thoughts and Behaviors [see Warnings and Precautions (5.4) ] Cataracts [see Warnings and Precautions (5.6) ] The most common adverse drug reactions to KALYDECO (≥8% of patients with CF who have a G551D mutation in the CFTR gene) were headache, oropharyngeal pain, upper respiratory tract infection, nasal congestion, abdominal pain, nasopharyngitis, diarrhea, rash, nausea, and dizziness. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Vertex Pharmaceuticals Incorporated at 1-877-634-8789 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The overall safety profile of KALYDECO is based on pooled data from three placebo-controlled clinical trials conducted in 353 patients 6 years of age and older with CF who had a G551D…
Who shouldn’t take ivacaftor
None. None ( 4 )
Ivacaftor drug interactions
Potential for other drugs to affect ivacaftor CYP3A inhibitors: Reduce KALYDECO dosage in patients aged 6 months and older when co-administered with strong CYP3A inhibitors (e.g., ketoconazole) or moderate CYP3A inhibitors (e.g., fluconazole). KALYDECO is not recommended in patients aged 1 month to less than 6 months when co-administered with strong or moderate CYP3A inhibitors. Avoid food or drink containing grapefruit. ( 2.4 , 7.1 ) 7.1 Inhibitors of CYP3A Ivacaftor is a sensitive CYP3A substrate. Co-administration with ketoconazole, a strong CYP3A inhibitor, significantly increased ivacaftor exposure [measured as area under the curve (AUC)] by 8.5-fold. Based on simulations of these results, a reduction of the KALYDECO dosage is recommended for patients aged 6 months and older taking concomitant strong CYP3A inhibitors, such as ketoconazole, itraconazole, posaconazole, voriconazole, telithromycin, and clarithromycin. KALYDECO is not recommended for patients less than 6 months of age taking strong CYP3A inhibitors [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3) ] . Co-administration with fluconazole, a moderate inhibitor of CYP3A, increased ivacaftor exposure by 3-fold. Therefore, a reduction of the KALYDECO dosage is recommended for patients aged 6 months and older taking concomitant moderate CYP3A inhibitors, such as fluconazole and erythromycin. KALYDECO is not recommended for patients less than 6 months of age taking moderate CYP3A inhibitors [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3) ] . Co-administration of KALYDECO with grapefruit juice, which contains one or more components that moderately inhibit CYP3A, may increase exposure of ivacaftor. Therefore, avoid food or drink containing grapefruit during treatment with KALYDECO [ see Clinical Pharmacology (12.3) ]. 7.2 Inducers of CYP3A Co-administration with rifampin, a strong CYP3A inducer, significantly decreased ivacaftor exposure (AUC) by approximately 9-fold. Therefore, co-administration with strong CYP3A inducers, such as rifampin, rifabutin, phenobarbital, carbamazepine, phenytoin, and St. John's wort is not recommended [ see Warnings and Precautions (5.5) and Clinical Pharmacology (12.3) ]. 7.3 Ciprofloxacin Co-administration of KALYDECO with ciprofloxacin had no effect on the exposure of ivacaftor. Therefore, no dosage adjustment is necessary during concomitant administration of KALYDECO with ciprofloxacin [ see Clinical Pharmacology (12.3) ]. Potential for ivacaftor to affect other drugs 7.4 CYP2C9 Substrates Ivacaftor may inhibit CYP2C9; therefore, monitoring of the international normalized ratio (INR) during co-administration of KALYDECO with warfarin is recommended. Other therapeutic products for which exposure may be increased by KALYDECO include glimepiride and glipizide; these therapeutic products should be used with caution [see Clinical Pharmacology (12.3) ] . 7.5 CYP3A and/or P-gp Substrates Ivacaftor and its M1 metabolite have the potential to inhibit CYP3A and P-gp. Co-administration with oral midazolam, a sensitive CYP3A substrate, increased midazolam exposure 1.5-fold, consistent with weak inhibition of CYP3A by ivacaftor. Co-administration with digoxin, a sensitive P-gp substrate, increased digoxin exposure by 1.3-fold, consistent with weak inhibition of P-gp by ivacaftor. Administration of KALYDECO may increase systemic exposure of drugs that are substrates of CYP3A and/or P-gp, which may increase or prolong their therapeutic effect and adverse events. Therefore, caution and appropriate monitoring are recommended when co-administering KALYDECO with sensitive CYP3A and/or P-gp substrates, such as digoxin, cyclosporine, and tacrolimus [ see Clinical Pharmacology (12.3) ].
Every ivacaftor product we track (2)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 64/100 | Prescription | Powder | No data | — | View → | |
| 2 | Not yet rated | Prescription | Powder | No data | — | View → |
What ivacaftor pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| V;150 | 150 mg | blue | oval | — |
Combination products containing ivacaftor
A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.
How long ivacaftor keeps
No ivacaftor label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Does ivacaftor expire? The in-use limits and storage rules from its labelsIvacaftor and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for ivacaftor: levels in milk, effects in breastfed infants, and the drugs it would consider insteadMaternal ivacaftor therapy produce low levels in milk and very low levels in the serum of breastfed infants. An international survey of cystic fibrosis (CF) centers found no adverse effects in breastfed infants of mothers taking these drugs and a task force respiratory experts from Europe, Australia and New Zealand found that these drugs are probably safe during breastfeeding. Infants exposed to CFTR modulators through breastmilk should have periodic liver function testing and an examination by an ophthalmologist for cataracts. Because CFTR modulators can mask cystic fibrosis in breastfed infants, testing of breastfed infants for CF should be performed. Detailed monitoring recommendations have been published.
National Institute of Child Health and Human Development, record revised May 15, 2026. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about ivacaftor
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 4,478 reports naming ivacaftor, and the FDA flagged 92% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- hospitalisation984 reports
- lower respiratory tract infection206 reports
- infective pulmonary exacerbation of cystic fibrosis182 reports
- anxiety121 reports
- malaise119 reports
- exposure during pregnancy102 reports
- depression101 reports
- cystic fibrosis96 reports
Read these as a signal, not a rate. A report does not mean ivacaftor caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved August 25, 2026.
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Frequently asked questions
What is ivacaftor?
Kalydeco (Ivacaftor) is a cystic fibrosis transmembrane conductance regulator potentiator used to treat Cystic Fibrosis.
What kind of drug is ivacaftor?
The FDA classifies ivacaftor as a cystic fibrosis transmembrane conductance regulator potentiator. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take ivacaftor with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run ivacaftor against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is ivacaftor sold under?
We track 2 ivacaftor-containing products in the U.S.: Ivacaftor and Kalydeco. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does ivacaftor come in?
Across the brands we track, ivacaftor is currently marketed as powder and tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic ivacaftor?
Yes. Our catalog lists 1 generic ivacaftor product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Cite this page
- APA
- pharmaranks. (2026, July 24). Ivacaftor: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/ivacaftor
- MLA
- “Ivacaftor: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/ivacaftor.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for ivacaftor on DailyMed (NIH) ↗.