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Ivacaftor

Pronunciation

(eye va KAF tor)

Index Terms

  • VX-770

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Packet, Oral:

Kalydeco: 50 mg (56 ea); 75 mg (56 ea)

Tablet, Oral:

Kalydeco: 150 mg [contains fd&c blue #2 (indigotine)]

Brand Names: U.S.

  • Kalydeco

Pharmacologic Category

  • Cystic Fibrosis Transmembrane Conductance Regulator Potentiator

Pharmacology

Potentiates epithelial cell chloride ion transport of defective (G551D mutant) cell-surface CFTR protein thereby improving the regulation of salt and water absorption and secretion in various tissues (eg, lung, GI tract).

Absorption

Variable; increased (by 2.5- to 4-fold) with fatty foods

Distribution

Vd: 353 L ± 122 L

Metabolism

Hepatic; extensive via CYP3A; forms 2 major metabolites (M1 [active; 1/6 potency] and M6 [inactive])

Excretion

Feces (87.8%, ~65% of administered dose as metabolites); urine (minimal, as unchanged drug)

Onset of Action

FEV1 increased, sweat chloride decreased within ~2 weeks

Time to Peak

~4 hours

Half-Life Elimination

~12 hours

Protein Binding

~99%; primarily to alpha1 acid glycoprotein, albumin

Special Populations: Hepatic Function Impairment

Adults with moderate hepatic impairment (Child-Pugh class B) had an ~2-fold increase in ivacaftor AUC0 to ∞; in adults with mild hepatic impairment (Child-Pugh class A), increase is expected to be <2-fold. The magnitude of increase in exposure in patients with severe hepatic impairment (Child-Pugh class C) is expected to be substantially higher than that observed in patients with moderate hepatic impairment.

Use: Labeled Indications

Cystic fibrosis:

US labeling: Treatment of cystic fibrosis (CF) in patients ≥2 years of age who have one mutation in the CF transmembrane conductance regulator (CFTR) gene that is responsive to ivacaftor potentiation based on clinical and/or in vitro assay data.

If the patient's genotype is unknown, an FDA-cleared CF mutation test should be used to detect the presence of a CFTR mutation followed by verification with bidirectional sequencing when recommended by the mutation test instructions for use.

Canadian labeling:

Tablets: Treatment of CF in patients ≥6 years of age and weighing ≥25 kg who have one of the following mutations in the CFTR gene: G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, S549R, or G970R; treatment of CF in patients ≥18 years of age with an R117H mutation in the CFTR gene.

Granules: Treatment of CF in patients ≥2 years of age and weighing <25 kg who have one of the following mutations in the CFTR gene: G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, S549R, or G970R.

Limitations of use: According to the manufacturer labeling, ivacaftor is not effective in patients with CF who are homozygous for the F508del mutation in the CFTR gene.

Contraindications

There are no contraindications listed in the manufacturer's labeling.

Canadian labeling: Additional contraindications (not in US labeling): Hypersensitivity to ivacaftor or any component of the formulation.

Dosing: Adult

Cystic fibrosis: Oral: Tablet: 150 mg every 12 hours

Dosage adjustment for ivacaftor with concomitant medications:

CYP3A strong inhibitors (eg, ketoconazole, itraconazole, posaconazole, voriconazole, clarithromycin, telithromycin): 150 mg twice weekly

CYP3A moderate inhibitors (eg, erythromycin, fluconazole): 150 mg once daily

CYP3A strong inducers (eg, carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin, St. John's wort): Use is not recommended.

Missed dose: If dose is missed within 6 hours of the usual time it is taken, take the dose as soon as possible; otherwise, skip the missed dose and resume the normal dosing schedule.

Dosing: Pediatric

Cystic fibrosis: Oral:

Granules:

Children 2 to <6 years of age:

<14 kg: 50 mg packet every 12 hours

≥14 kg: 75 mg packet every 12 hours

Tablet: Children ≥6 years of age and Adolescents: Refer to adult dosing.

Dosage adjustment for ivacaftor with concomitant medications:

CYP3A strong inhibitors (eg, clarithromycin, itraconazole, ketoconazole, posaconazole, telithromycin, voriconazole):

Children 2 to <6 years of age:

<14 kg: 50 mg granule packet twice weekly

≥14 kg: 75 mg granule packet twice weekly

Children ≥6 years of age and Adolescents: Refer to adult dosing.

CYP3A moderate inhibitors (eg, erythromycin, fluconazole):

Children 2 to <6 years of age:

<14 kg: 50 mg granule packet once daily

≥14 kg: 75 mg granule packet once daily

Children ≥6 years of age and Adolescents: Refer to adult dosing.

CYP3A strong inducers (eg, carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin, St. John's wort): Refer to adult dosing.

Missed dose: Refer to adult dosing.

Dosing: Renal Impairment

CrCl >30 mL/minute: No dosage adjustment necessary (has not been studied).

CrCl ≤30 mL/minute: There are no dosage adjustments provided in the manufacturer's labeling (has not been studied); use with caution.

End-stage renal disease (ESRD): There are no dosage adjustments provided in the manufacturer's labeling (has not been studied); use with caution.

Dosing: Hepatic Impairment

Mild impairment (Child-Pugh class A): No dosage adjustment necessary.

Moderate impairment (Child-Pugh class B):

Children 2 to <6 years of age:

<14 kg: 50 mg granule packet once daily

≥14 kg: 75 mg granule packet once daily

Children ≥6 years of age, Adolescents, and Adults: 150 mg once daily

Severe impairment (Child-Pugh class C): Has not been studied; use with caution.

Children 2 to <6 years of age:

<14 kg: 50 mg granule packet once daily or less frequently

≥14 kg: 75 mg granule packet once daily or less frequently

Children ≥6 years of age, Adolescents, and Adults: 150 mg once daily or less frequently

Dosing: Adjustment for Toxicity

ALT or AST >5 times ULN: Hold ivacaftor; may resume if elevated transaminases resolved and after assessing benefits vs risks of continued treatment.

Administration

Oral: Administer before or after high-fat-containing foods (eg, butter, cheese pizza, eggs, peanut butter, whole-milk dairy products [eg, whole milk, cheese, yogurt]).

Granules: Mix entire packet of granules with 5 mL of soft food (eg, pureed fruits [excluding grapefruit or Seville oranges] or vegetables, yogurt, applesauce) or liquid (eg, water, milk, juice [excluding grapefruit juice]); food or liquid should be at or below room temperature. Granule mixture should be completely consumed within 1 hour.

Dietary Considerations

Avoid grapefruit or Seville oranges.

Storage

Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F); after mixing the granules, the product is stable for 1 hour.

Drug Interactions

Afatinib: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Afatinib. Management: Per US labeling: reduce afatinib by 10mg if not tolerated. Per Canadian labeling: avoid combination if possible; if used, administer the P-gp inhibitor simultaneously with or after the dose of afatinib. Consider therapy modification

Amodiaquine: CYP2C8 Inhibitors may increase the serum concentration of Amodiaquine. Avoid combination

ARIPiprazole: CYP3A4 Inhibitors (Weak) may increase the serum concentration of ARIPiprazole. Management: Monitor for increased aripiprazole pharmacologic effects. Aripiprazole dose adjustments may or may not be required based on concomitant therapy and/or indication. Consult full interaction monograph for specific recommendations. Monitor therapy

Betrixaban: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Betrixaban. Management: Decrease the betrixaban dose to an initial single dose of 80 mg followed by 40 mg once daily if combined with a P-glycoprotein inhibitor. Consider therapy modification

Bilastine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Bilastine. Management: Consider alternatives when possible; bilastine should be avoided in patients with moderate to severe renal insufficiency who are receiving p-glycoprotein inhibitors. Consider therapy modification

Bitter Orange: May increase the serum concentration of Ivacaftor. Avoid combination

Bosentan: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Brentuximab Vedotin: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Brentuximab Vedotin. Specifically, concentrations of the active monomethyl auristatin E (MMAE) component may be increased. Monitor therapy

Celiprolol: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Celiprolol. Monitor therapy

Colchicine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Colchicine. Colchicine distribution into certain tissues (e.g., brain) may also be increased. Management: Colchicine is contraindicated in patients with impaired renal or hepatic function who are also receiving a p-glycoprotein inhibitor. In those with normal renal and hepatic function, reduce colchicine dose as directed. Consider therapy modification

Conivaptan: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

CYP3A4 Inducers (Moderate): May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

CYP3A4 Inducers (Strong): May decrease the serum concentration of Ivacaftor. Avoid combination

CYP3A4 Inhibitors (Moderate): May increase the serum concentration of Ivacaftor. Management: Ivacaftor dose reductions are required; consult full monograph content for specific age- and weight-based recommendations. No dose adjustment is needed when using ivacaftor/lumacaftor with a moderate CYP3A4 inhibitor. Consider therapy modification

CYP3A4 Inhibitors (Strong): May increase the serum concentration of Ivacaftor. Management: Ivacaftor dose reductions are required; consult full monograph content for specific age- and weight-based recommendations. Consider therapy modification

Dabigatran Etexilate: P-glycoprotein/ABCB1 Inhibitors may increase serum concentrations of the active metabolite(s) of Dabigatran Etexilate. Management: Dabigatran dose reductions may be needed. Specific recommendations vary considerably according to US vs Canadian labeling, specific P-gp inhibitor, renal function, and indication for dabigatran treatment. Refer to full monograph or dabigatran labeling. Consider therapy modification

Dabrafenib: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Seek alternatives to the CYP3A4 substrate when possible. If concomitant therapy cannot be avoided, monitor clinical effects of the substrate closely (particularly therapeutic effects). Consider therapy modification

Dasatinib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Deferasirox: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Dofetilide: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Dofetilide. Monitor therapy

DOXOrubicin (Conventional): P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of DOXOrubicin (Conventional). Management: Seek alternatives to P-glycoprotein inhibitors in patients treated with doxorubicin whenever possible. One U.S. manufacturer (Pfizer Inc.) recommends that these combinations be avoided. Consider therapy modification

Edoxaban: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Edoxaban. Management: See full monograph for details. Reduced doses are recommended for patients receiving edoxaban for venous thromboembolism in combination with certain inhibitors. Similar dose adjustment is not recommended for edoxaban use in atrial fibrillation. Consider therapy modification

Everolimus: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Everolimus. Management: Everolimus dose reductions are required for patients being treated for subependymal giant cell astrocytoma or renal cell carcinoma. See prescribing information for specific dose adjustment and monitoring recommendations. Consider therapy modification

Flibanserin: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Flibanserin. Monitor therapy

Fosaprepitant: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Fusidic Acid (Systemic): May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

Grapefruit Juice: May increase the serum concentration of Ivacaftor. Avoid combination

HYDROcodone: CYP3A4 Inhibitors (Weak) may increase the serum concentration of HYDROcodone. Monitor therapy

Idelalisib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

Lomitapide: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Lomitapide. Management: Patients on lomitapide 5 mg/day may continue that dose. Patients taking lomitapide 10 mg/day or more should decrease the lomitapide dose by half. The lomitapide dose may then be titrated up to a max adult dose of 30 mg/day. Consider therapy modification

MiFEPRIStone: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Minimize doses of CYP3A4 substrates, and monitor for increased concentrations/toxicity, during and 2 weeks following treatment with mifepristone. Avoid cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus, and tacrolimus. Consider therapy modification

Naldemedine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Naldemedine. Monitor therapy

Naloxegol: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Naloxegol. Monitor therapy

NiMODipine: CYP3A4 Inhibitors (Weak) may increase the serum concentration of NiMODipine. Monitor therapy

Palbociclib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

PAZOPanib: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of PAZOPanib. Avoid combination

P-glycoprotein/ABCB1 Substrates: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of P-glycoprotein/ABCB1 Substrates. P-glycoprotein inhibitors may also enhance the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Monitor therapy

Pimozide: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Pimozide. Avoid combination

Pitolisant: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Combined use of pitolisant with a CYP3A4 substrate that has a narrow therapeutic index should be avoided. Other CYP3A4 substrates should be monitored more closely when used with pitolisant. Consider therapy modification

Prucalopride: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Prucalopride. Monitor therapy

Ranolazine: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Ranolazine. Monitor therapy

RifAXIMin: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of RifAXIMin. Monitor therapy

Sarilumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Silodosin: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Silodosin. Avoid combination

Siltuximab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Simeprevir: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

St John's Wort: May decrease the serum concentration of Ivacaftor. Avoid combination

Stiripentol: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Use of stiripentol with CYP3A4 substrates that are considered to have a narrow therapeutic index should be avoided due to the increased risk for adverse effects and toxicity. Any CYP3A4 substrate used with stiripentol requires closer monitoring. Consider therapy modification

Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Topotecan: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Topotecan. Avoid combination

Venetoclax: P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of Venetoclax. Management: Reduce the venetoclax dose by at least 50% in patients requiring these combinations. Consider therapy modification

VinCRIStine (Liposomal): P-glycoprotein/ABCB1 Inhibitors may increase the serum concentration of VinCRIStine (Liposomal). Avoid combination

Adverse Reactions

Frequency not always defined.

>10%:

Central nervous system: Headache (24%)

Dermatologic: Skin rash (13%)

Gastrointestinal: Abdominal pain (16%), diarrhea (13%), nausea (12%)

Respiratory: Oropharyngeal pain (22%), upper respiratory tract infection (22%), nasal congestion (20%), nasopharyngitis (15%)

1% to 10%:

Central nervous system: Dizziness (9%)

Dermatologic: Acne vulgaris (4% to 7%)

Endocrine & metabolic: Increased serum glucose (4% to 7%), hypoglycemia

Hepatic: Increased liver enzymes (4% to 7%), increased serum ALT (4% to 7%)

Neuromuscular & skeletal: Arthralgia (4% to 7%), musculoskeletal chest pain (4% to 7%), myalgia (4% to 7%)

Ophthalmic: Cataract (children ≤12)

Respiratory: Change in bronchial secretions (4% to 7%; bacteria present), pharyngeal erythema (4% to 7%), pleuritic chest pain (4% to 7%), rhinitis (4% to 7%), sinus congestion (4% to 7%), sinus headache (4% to 7%), wheezing (4% to 7%)

Miscellaneous: Bacteria in sputum (4% to 7%)

Warnings/Precautions

Concerns related to adverse effects:

• Cataracts: Noncongenital lens opacities and cataracts have been reported in pediatric patients treated with ivacaftor; other risk factors were present in some cases (eg, corticosteroid use, exposure to radiation), but a possible risk related to ivacaftor cannot be excluded. Baseline and follow-up ophthalmological examinations are recommended in pediatric patients.

• CNS effects: May cause dizziness, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving).

• Hepatic effects: May increase hepatic transaminases. Monitor liver function; increased monitoring may be necessary in patients with a history of elevated hepatic transaminases. Temporarily discontinue treatment if ALT or AST >5 times ULN. Following resolution of transaminase elevations, consider the benefits and risks of resuming therapy.

Disease-related concerns:

• Hepatic impairment: Use with caution in patients with hepatic impairment; dosage adjustment recommended in patients with moderate to severe (Child-Pugh class B or C) impairment.

• Renal impairment: Use with caution in patients with severe renal impairment (CrCl ≤30 mL/minute) or ESRD.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Monitoring Parameters

CF mutation test (prior to therapy initiation if G551D mutation status unknown); ALT/AST at baseline, every 3 months for 1 year, then annually thereafter or as clinically indicated (consider more frequent monitoring in patients with a history of elevated hepatic transaminases); FEV1; baseline and follow-up ophthalmological exams in pediatric patients

Pregnancy Considerations

Information related to ivacaftor use in pregnancy is limited (Kaminski 2016; Ladores 2017; Marco 2015).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience headache, dizziness, pharyngitis, rhinitis, rhinorrhea, diarrhea, abdominal pain, nausea, acne, joint pain, or muscle pain. Have patient report immediately to prescriber signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), signs of low blood sugar (dizziness, headache, fatigue, feeling weak, shaking, tachycardia, confusion, increased hunger, or sweating), signs of high blood sugar (confusion, fatigue, increased thirst, increased hunger, polyuria, flushing, fast breathing, or breath that smells like fruit), angina, or vision changes (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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