Ivacaftor Win Medica: Uses, Dosage & Side Effects
A CFTR potentiator for the treatment of cystic fibrosis in patients aged 6 years and older with specific CFTR gating mutations
Ivacaftor Win Medica (ivacaftor) is a prescription CFTR potentiator indicated for the treatment of cystic fibrosis (CF) in patients aged 6 years and older who weigh at least 25 kg and carry one of several specific gating mutations in the CFTR gene, including the most common gating mutation G551D. Unlike corrector therapies that address protein folding, ivacaftor works by directly enhancing the channel-open probability of CFTR protein that has reached the cell surface but functions abnormally. By restoring chloride and bicarbonate ion transport, ivacaftor improves hydration of airway surfaces, enhances mucociliary clearance, and reduces the viscosity of secretions throughout the body. Clinical trials have demonstrated significant improvements in lung function (FEV1), body weight, pulmonary exacerbation frequency, sweat chloride levels, and patient-reported quality of life.
Quick Facts: Ivacaftor Win Medica
Key Takeaways
- Ivacaftor Win Medica is a CFTR potentiator that directly enhances the gating function of defective CFTR protein in patients with cystic fibrosis carrying specific gating mutations such as G551D, the most prevalent gating mutation affecting approximately 4–5% of all CF patients worldwide.
- The standard adult and adolescent dose is one 150 mg tablet taken every 12 hours with fat-containing food, which is essential for adequate drug absorption; without fat, bioavailability drops by 2 to 4 times.
- Landmark clinical trials (STRIVE and ENVISION) demonstrated mean absolute improvements in FEV1 of approximately 10 percentage points, significant weight gain, and a 55% reduction in pulmonary exacerbations compared to placebo.
- Liver function tests (ALT and AST) must be monitored before starting treatment, every 3 months during the first year, and annually thereafter, as transaminase elevations are a recognized adverse effect.
- Strong CYP3A inhibitors (such as ketoconazole, itraconazole, and clarithromycin) require dose reduction to 150 mg twice a week, while strong CYP3A inducers (such as rifampicin and St. John’s Wort) should be avoided due to substantial reductions in ivacaftor exposure.
What Is Ivacaftor Win Medica and What Is It Used For?
Ivacaftor Win Medica contains the active substance ivacaftor, a small-molecule compound that belongs to a class of drugs known as CFTR potentiators. Cystic fibrosis is a life-shortening autosomal recessive genetic disorder caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The CFTR protein functions as a chloride and bicarbonate ion channel on the apical surface of epithelial cells lining the airways, gastrointestinal tract, pancreatic ducts, sweat glands, and reproductive organs. When the CFTR protein is absent or dysfunctional, chloride and bicarbonate transport is impaired, leading to dehydrated, abnormally thick and sticky mucus that obstructs airways, promotes chronic bacterial infections, and causes progressive organ damage.
More than 2,000 mutations in the CFTR gene have been identified, classified into six classes based on the type of protein defect they cause. Ivacaftor specifically targets Class III gating mutations, in which the CFTR protein is correctly synthesized and reaches the cell surface but has a severely reduced channel-open probability. The most common gating mutation is G551D (glycine to aspartate substitution at position 551), which is present in approximately 4–5% of all CF patients worldwide—roughly 3,000–4,000 individuals globally. In patients with the G551D mutation, the CFTR channel is present at the cell surface but opens for only about 1% of the normal duration, resulting in dramatically reduced chloride transport.
Ivacaftor works by binding to the CFTR protein and increasing its channel-open probability (gating activity). In vitro studies have demonstrated that ivacaftor increases the open probability of the G551D-CFTR channel by approximately 10-fold, restoring chloride transport to approximately 35–50% of normal levels. This is a clinically meaningful level of restoration, as studies suggest that even 10–25% of normal CFTR function can significantly attenuate the disease phenotype. Beyond chloride, ivacaftor also enhances bicarbonate transport, which plays a critical role in normalizing airway surface liquid pH and antimicrobial defense mechanisms.
The clinical efficacy of ivacaftor was established in two pivotal phase III randomized, double-blind, placebo-controlled trials. The STRIVE trial enrolled 161 patients aged 12 years and older with at least one G551D-CFTR mutation and an FEV1 between 40% and 105% predicted at baseline. After 24 weeks, patients treated with ivacaftor experienced a mean absolute improvement in percent predicted FEV1 of 10.6 percentage points compared to placebo (p < 0.001), with improvements evident as early as Day 15. At 48 weeks, the treatment difference was sustained at 10.5 percentage points. Additionally, patients in the ivacaftor group experienced a 55% reduction in the risk of pulmonary exacerbations, gained an average of 2.7 kg more body weight than placebo, and demonstrated a mean reduction in sweat chloride of 48.1 mmol/L, bringing values close to or below the diagnostic threshold for CF.
The ENVISION trial enrolled 52 patients aged 6 to 11 years with at least one G551D mutation. At 24 weeks, the mean absolute improvement in percent predicted FEV1 was 12.5 percentage points compared to placebo (p < 0.0001). Weight gain and sweat chloride reduction mirrored the findings in the adult population. Subsequent extension studies and post-marketing data have confirmed that the benefits of ivacaftor are sustained over several years of continuous treatment, with some patients maintaining their improved lung function for more than 5 years.
Ivacaftor Win Medica is indicated for patients aged 6 years and older weighing at least 25 kg who have one of the following CFTR gating mutations on at least one allele: G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, or S549R. A confirmed diagnosis of cystic fibrosis with genotyping to confirm the presence of one of these mutations is mandatory before initiating treatment. Ivacaftor was the first CFTR modulator therapy to receive regulatory approval, with the U.S. Food and Drug Administration (FDA) granting approval in January 2012 and the European Medicines Agency (EMA) following in July 2012. It represented a paradigm shift in CF treatment by moving from symptom management to addressing the underlying molecular defect.
In healthy individuals, the CFTR protein opens and closes like a gate to allow chloride ions to pass through the cell membrane. In patients with gating mutations, this gate is stuck nearly closed even though the protein reaches the cell surface normally. Ivacaftor acts like a key that helps unlock this gate, allowing chloride to flow more freely. This reduces the thickness of mucus in the lungs and other organs, improving breathing and overall organ function.
What Should You Know Before Taking Ivacaftor Win Medica?
Contraindications
Ivacaftor Win Medica is contraindicated in patients with known hypersensitivity to ivacaftor or to any of the excipients contained in the formulation. Although severe hypersensitivity reactions to ivacaftor are rare, any patient who develops symptoms suggestive of a serious allergic reaction (such as widespread rash, urticaria, angioedema, or difficulty breathing) should discontinue the medication and seek immediate medical attention. There are no other absolute contraindications; however, there are several important precautions and warnings that must be carefully considered.
Warnings and Precautions
Hepatic effects: Elevated transaminases (ALT and AST) have been observed in clinical trials and post-marketing experience with ivacaftor. In the pivotal STRIVE trial, ALT or AST elevations greater than 3 times the upper limit of normal (ULN) occurred in 5.3% of ivacaftor-treated patients compared to 2.5% of placebo-treated patients. More significant elevations (greater than 8 times ULN) have also been reported. Liver function tests (ALT and AST) must be assessed before initiating ivacaftor, every 3 months during the first year of treatment, and annually thereafter. If ALT or AST exceeds 5 times ULN, treatment should be interrupted until the transaminase levels resolve. The decision to resume therapy should be carefully weighed against the potential benefits and risks. Patients with pre-existing hepatic impairment require particular caution and may need dose adjustments.
Hepatic impairment: Ivacaftor is extensively metabolized by the liver. In patients with moderate hepatic impairment (Child-Pugh Class B), the dose should be reduced to one 150 mg tablet once daily. No studies have been conducted in patients with severe hepatic impairment (Child-Pugh Class C), and use is not recommended in this population unless the benefits outweigh the risks, in which case a dose of 150 mg once daily or less frequently should be used with careful monitoring.
Cataracts: Cases of non-congenital lens opacities (cataracts) without impact on vision have been reported in pediatric patients treated with ivacaftor. While a causal relationship has not been definitively established, baseline and follow-up ophthalmological examinations are recommended in pediatric patients beginning ivacaftor treatment.
Renal impairment: No dose adjustment is recommended for patients with mild to moderate renal impairment. Caution is advised in patients with severe renal impairment (creatinine clearance ≤ 30 mL/min) or end-stage renal disease, as ivacaftor has not been formally studied in these populations.
Liver function tests (ALT and AST) must be performed before starting Ivacaftor Win Medica, every 3 months during the first year, and annually thereafter. If ALT or AST exceeds 5 times the upper limit of normal, or if ALT or AST exceeds 3 times the upper limit with bilirubin exceeding 2 times the upper limit, treatment should be interrupted immediately. Contact your healthcare provider if you experience unexplained nausea, vomiting, abdominal pain, jaundice, dark urine, or unusual fatigue.
Pregnancy and Breastfeeding
Pregnancy: There are limited clinical data on the use of ivacaftor in pregnant women. Animal reproductive toxicology studies in rats and rabbits at doses up to approximately 5 times and 6 times the maximum recommended human dose (based on summed AUCs of ivacaftor and its metabolites) did not reveal evidence of teratogenicity or adverse effects on fertility. However, a slight reduction in fetal and pup body weight was observed in rats at the highest dose tested. As a precautionary measure, Ivacaftor Win Medica should only be used during pregnancy if the potential clinical benefit justifies the potential risk to the fetus. Women of childbearing potential should discuss contraception and family planning with their physician.
Breastfeeding: It is not known whether ivacaftor or its metabolites are excreted in human breast milk. Ivacaftor was detected in the milk of lactating rats. A risk to the breastfed infant cannot be excluded. A decision must be made whether to discontinue breastfeeding or to discontinue ivacaftor therapy, taking into account the benefit of breastfeeding for the child and the benefit of therapy for the mother.
Fertility: No data on the effect of ivacaftor on human fertility are available. Ivacaftor did not impair fertility in male or female rats at doses resulting in exposures up to approximately 5 times the maximum recommended human dose. It is worth noting that cystic fibrosis itself is associated with reduced fertility, particularly in males due to congenital bilateral absence of the vas deferens (CBAVD). Improvement of CFTR function with ivacaftor may have implications for reproductive potential, and patients should be counseled accordingly.
How Does Ivacaftor Win Medica Interact with Other Drugs?
Ivacaftor is extensively metabolized by the CYP3A enzyme system. The major circulating metabolite, M1 (hydroxymethyl-ivacaftor), has approximately one-sixth the pharmacological potency of ivacaftor and is considered pharmacologically active. The M6 metabolite has approximately one-fiftieth the potency and is not considered clinically relevant. Because of this dependence on CYP3A-mediated metabolism, ivacaftor is susceptible to significant pharmacokinetic drug interactions with substances that inhibit or induce CYP3A activity. In addition, ivacaftor has been shown to be a weak inhibitor of both CYP3A and P-glycoprotein (P-gp), meaning it can increase the plasma levels of drugs that are substrates for these pathways.
Major Interactions
Co-administration of ivacaftor with strong CYP3A inhibitors is the most clinically significant drug interaction. When 150 mg ivacaftor was co-administered with ketoconazole 400 mg once daily (a strong CYP3A inhibitor), ivacaftor exposure (AUC) increased by approximately 8.5-fold. This dramatic increase in exposure could amplify adverse effects, particularly hepatotoxicity. For patients who must take strong CYP3A inhibitors (such as ketoconazole, itraconazole, posaconazole, voriconazole, telithromycin, or clarithromycin), the dose of Ivacaftor Win Medica should be reduced to 150 mg twice a week.
Conversely, strong CYP3A inducers dramatically reduce ivacaftor exposure. Co-administration with rifampicin 600 mg once daily decreased ivacaftor AUC by approximately 89%. At such reduced exposure levels, ivacaftor is unlikely to provide meaningful clinical benefit. Therefore, co-administration with strong CYP3A inducers (such as rifampicin, rifabutin, phenobarbital, carbamazepine, phenytoin, and St. John’s Wort) should be avoided.
Minor Interactions
Moderate CYP3A inhibitors (such as fluconazole and erythromycin) are expected to increase ivacaftor exposure by approximately 2 to 3-fold. The dose of Ivacaftor Win Medica should be reduced to 150 mg once daily when co-administered with moderate CYP3A inhibitors. Grapefruit juice contains one or more components that inhibit CYP3A and could increase ivacaftor exposure. Patients should avoid grapefruit juice and Seville oranges during treatment.
Ivacaftor is a weak inhibitor of CYP3A and P-gp. Co-administration of ivacaftor with midazolam (a sensitive CYP3A substrate) increased midazolam AUC by approximately 1.5-fold. Patients receiving CYP3A-substrate or P-gp-substrate drugs with a narrow therapeutic index (such as digoxin, cyclosporine, tacrolimus, or everolimus) should be monitored with appropriate dose adjustments as necessary.
| Interacting Drug | Type | Effect on Ivacaftor | Dose Adjustment |
|---|---|---|---|
| Ketoconazole, Itraconazole, Posaconazole, Voriconazole | Strong CYP3A inhibitor | AUC increased ~8.5-fold | Reduce to 150 mg twice weekly |
| Clarithromycin, Telithromycin | Strong CYP3A inhibitor | AUC increased ~8-fold (estimated) | Reduce to 150 mg twice weekly |
| Fluconazole, Erythromycin | Moderate CYP3A inhibitor | AUC increased ~2–3-fold | Reduce to 150 mg once daily |
| Rifampicin, Rifabutin | Strong CYP3A inducer | AUC decreased ~89% | Avoid co-administration |
| Carbamazepine, Phenytoin, Phenobarbital | Strong CYP3A inducer | Substantially decreased exposure | Avoid co-administration |
| St. John’s Wort | Strong CYP3A inducer | Substantially decreased exposure | Avoid co-administration |
| Grapefruit juice | CYP3A inhibitor (dietary) | Increased exposure (extent unknown) | Avoid during treatment |
| Digoxin, Cyclosporine | P-gp substrate | Ivacaftor may increase their levels | Monitor and adjust as needed |
Patients taking Ivacaftor Win Medica should avoid grapefruit and grapefruit juice, as well as Seville (bitter) oranges and their products. These fruits contain natural substances that inhibit CYP3A enzymes in the gut and liver, which can unpredictably increase ivacaftor blood levels and increase the risk of side effects.
What Is the Correct Dosage of Ivacaftor Win Medica?
Ivacaftor Win Medica should only be prescribed by physicians experienced in the treatment of cystic fibrosis. A confirmed CFTR genotype demonstrating one of the approved gating mutations on at least one allele must be obtained before initiating therapy. The medication must always be taken with fat-containing food to ensure adequate absorption. Examples of suitable fat-containing foods include eggs, butter, peanut butter, cheese pizza, avocado, whole-milk dairy products, and nuts. Taking ivacaftor without food containing fat results in approximately 2 to 4-fold lower drug exposure, which may compromise therapeutic efficacy.
Adults
Standard Adult Dosage (ages 18+ years)
150 mg (one film-coated tablet) taken orally every 12 hours with fat-containing food. The total daily dose is 300 mg. Treatment should continue for as long as clinical benefit is observed, and decisions to discontinue should be made by an experienced CF physician.
Children
Pediatric Dosage (ages 6 years and older, weighing ≥25 kg)
150 mg (one film-coated tablet) taken orally every 12 hours with fat-containing food. This is the same dose as in adults. For children under 6 years of age or weighing less than 25 kg, alternative formulations (such as granules) may be available and should be used as directed by the prescribing physician. The 150 mg film-coated tablet formulation of Ivacaftor Win Medica is not suitable for children under 25 kg, as the dose cannot be appropriately adjusted.
Elderly
Geriatric Dosage (ages 65+ years)
No specific dose adjustment is recommended for elderly patients based on age alone. However, given the natural decline in hepatic and renal function with age, liver function should be monitored more closely. Clinical experience with ivacaftor in patients aged 65 and older is very limited, as cystic fibrosis has historically been associated with reduced life expectancy. With advances in CF treatment, increasing numbers of patients are surviving into their sixth and seventh decades, making this population of growing relevance.
| Patient Group | Dose | Frequency | Notes |
|---|---|---|---|
| Adults & children ≥6 years (≥25 kg) | 150 mg | Every 12 hours | Take with fat-containing food |
| Moderate hepatic impairment (Child-Pugh B) | 150 mg | Once daily | Close monitoring of liver function |
| Severe hepatic impairment (Child-Pugh C) | 150 mg | Once daily or less | Not recommended unless benefit outweighs risk |
| With strong CYP3A inhibitors | 150 mg | Twice weekly | E.g. ketoconazole, itraconazole |
| With moderate CYP3A inhibitors | 150 mg | Once daily | E.g. fluconazole, erythromycin |
Missed Dose
If a dose is missed within 6 hours of the scheduled time, the patient should take the missed dose with fat-containing food as soon as possible and then resume the normal dosing schedule. If more than 6 hours have passed since the missed dose, the patient should skip the missed dose and take the next dose at the regularly scheduled time. The dose should not be doubled to make up for a missed dose. Consistent timing of doses approximately 12 hours apart is recommended to maintain stable drug plasma levels and optimal therapeutic effect.
Overdose
There is no specific antidote for ivacaftor overdose. In case of an overdose, treatment should consist of general supportive measures including monitoring of vital signs, liver function tests, and clinical status. Ivacaftor is highly protein-bound (approximately 99%), and therefore hemodialysis is unlikely to be effective in removing the drug from the circulation. The highest single dose administered in clinical trials was 800 mg, which was not associated with any dose-limiting toxicities. In the event of a suspected overdose, contact your local poison control center or emergency medical services immediately.
Ivacaftor absorption is critically dependent on fat intake. Taking the tablet on an empty stomach or with a low-fat meal can reduce drug levels in the blood by 2 to 4 times, potentially making the treatment less effective. Always take each dose with a meal or snack that contains fat, such as eggs, cheese, butter, avocado, peanut butter, or whole-milk yogurt.
What Are the Side Effects of Ivacaftor Win Medica?
Like all medicines, Ivacaftor Win Medica can cause side effects, although not everybody gets them. The safety profile of ivacaftor has been well characterized across clinical trials involving more than 350 patients with CF carrying gating mutations, as well as through extensive post-marketing surveillance. The most commonly reported adverse reactions are generally consistent with manifestations of the underlying disease (cystic fibrosis) or are recognized pharmacological effects of CFTR potentiation. The following side effect profile is based on pooled data from controlled clinical trials and ongoing pharmacovigilance reporting.
It is important to understand the frequency categories used to classify side effects. "Very common" means the side effect affects more than 1 in 10 patients. "Common" means it affects between 1 in 10 and 1 in 100 patients. "Uncommon" means it affects between 1 in 100 and 1 in 1,000 patients. "Rare" means it affects fewer than 1 in 1,000 patients. Patients should report any new, unusual, or persistent symptoms to their healthcare provider, even if they are not listed below.
Very Common
Affects more than 1 in 10 patients
- Headache
- Upper respiratory tract infections (common cold, nasal congestion, sore throat)
- Abdominal pain (stomach pain)
- Diarrhea
- Nasopharyngitis (inflammation of the nose and throat)
- Oropharyngeal pain (sore throat)
Common
Affects 1 in 10 to 1 in 100 patients
- Rash (skin rash)
- Nausea
- Dizziness
- Elevated transaminases (ALT and/or AST increase)
- Ear pain and ear discomfort
- Tinnitus (ringing in the ears)
- Rhinitis (runny nose)
- Sinus congestion
- Pharyngeal erythema (redness of the throat)
- Bacteria in sputum
- Breast mass (non-cancerous)
- Acne
Uncommon
Affects 1 in 100 to 1 in 1,000 patients
- Hepatic encephalopathy (in patients with pre-existing liver disease)
- Elevated bilirubin
- Gynecomastia (breast enlargement in males)
- Nipple inflammation or pain
- Irregular menstruation
Rare
Affects fewer than 1 in 1,000 patients
- Non-congenital lens opacities (cataracts) in pediatric patients
- Severe transaminase elevations (>8 times ULN)
- Jaundice (yellowing of the skin or eyes)
The elevation of liver transaminases (ALT and AST) deserves particular attention. In controlled clinical trials, incidence of transaminase elevations >3 times ULN was 5.3% in ivacaftor-treated patients versus 2.5% in placebo patients. Most elevations were asymptomatic and resolved with continued therapy or dose interruption. However, cases of severe hepatic injury, including some requiring hospitalization, have been reported in post-marketing experience. This underscores the critical importance of regular liver function monitoring as described in the warnings and precautions section.
Ear-related side effects, including ear pain, tinnitus, and ear congestion, have been noted in clinical trials at a higher frequency in ivacaftor-treated patients. These effects may be related to changes in CFTR-mediated fluid balance in the middle ear and are generally mild and transient. Some patients with CF have pre-existing middle ear disease, which may predispose them to these symptoms.
An interesting observation from clinical trials and real-world experience is that some side effects may actually reflect the pharmacological activity of ivacaftor. For example, the increase in breast mass or gynecomastia reported in some adolescent and adult patients may be related to improved nutritional status and hormonal changes associated with CFTR restoration. Similarly, changes in menstrual patterns in female patients may reflect improved reproductive endocrine function.
Contact your healthcare provider immediately if you experience: unexplained nausea, vomiting, or loss of appetite; yellowing of the skin or eyes (jaundice); dark-colored urine; pain in the upper right area of the abdomen; unexplained fatigue; severe or persistent rash; or any signs of a serious allergic reaction such as difficulty breathing, swelling of the face or throat, or severe widespread rash.
How Should You Store Ivacaftor Win Medica?
Ivacaftor Win Medica should be stored at temperatures not exceeding 30°C (86°F). The tablets should be kept in the original blister packaging to protect them from moisture and light. There are no special cold storage requirements for this medication—it does not need to be refrigerated. The storage conditions are straightforward and allow for easy transport and use in daily life, which is particularly important for CF patients who often need to carry their medications when traveling or attending school or work.
Keep this medicine out of the sight and reach of children. Children with cystic fibrosis should only take their medication under adult supervision, and the tablets should be stored in a safe location to prevent accidental ingestion by younger siblings or other children in the household. Do not use Ivacaftor Win Medica after the expiry date printed on the blister packaging and outer carton. The expiry date refers to the last day of that month.
Do not dispose of unused or expired medications via wastewater or household waste. Ask your pharmacist about the proper disposal method in accordance with local regulations. Proper medication disposal helps protect the environment and prevents accidental exposure. Many pharmacies and healthcare facilities offer medication take-back programs for safe disposal.
What Does Ivacaftor Win Medica Contain?
The active substance in Ivacaftor Win Medica is ivacaftor. Each film-coated tablet contains 150 mg of ivacaftor. Ivacaftor is a small-molecule organic compound with the chemical name N-(2,4-di-tert-butyl-5-hydroxyphenyl)-1,4-dihydro-4-oxoquinoline-3-carboxamide. It has a molecular weight of 392.49 g/mol and is practically insoluble in water, which explains the critical dependence on fat-containing food for adequate oral absorption.
The tablet core typically contains the following excipients: microcrystalline cellulose, lactose monohydrate, hypromellose acetate succinate, croscarmellose sodium, sodium laurilsulfate, colloidal anhydrous silica, and magnesium stearate. The film coating generally consists of polyvinyl alcohol, titanium dioxide (E171), macrogol (polyethylene glycol), talc, indigo carmine aluminium lake (E132), and carnauba wax. These excipients serve various functions including acting as fillers, binders, disintegrants, glidants, and lubricants to ensure consistent tablet performance and drug release.
Patients with known intolerance to lactose should be aware that each tablet contains lactose monohydrate. While the amount per tablet is relatively small, patients with rare hereditary galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should discuss this with their physician before starting treatment. The coloring agent indigo carmine (E132) gives the tablet its characteristic blue appearance and is used as an identification aid.
The tablets are capsule-shaped (oblong), light blue, and film-coated. They may be imprinted with identification markings on one or both sides. The tablets are packaged in PVC/PE/PVDC-aluminum blister packs and supplied in outer cartons. Each pack may contain 56 film-coated tablets (sufficient for 28 days of standard twice-daily dosing). Not all pack sizes may be marketed in all countries.
Frequently Asked Questions About Ivacaftor Win Medica
Ivacaftor Win Medica is a CFTR potentiator used to treat cystic fibrosis (CF) in patients aged 6 years and older who weigh at least 25 kg and carry specific CFTR gating mutations such as G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, or S549R. It works by enhancing the function of the defective CFTR protein at the cell surface, improving chloride transport and reducing the thickness of mucus in the lungs and other organs. Your physician must confirm your specific CFTR genotype before starting treatment.
Ivacaftor Win Medica should be taken as one 150 mg tablet every 12 hours (twice daily) with fat-containing food such as eggs, butter, peanut butter, cheese, avocado, or whole-milk dairy products. Fat-containing food is essential because it significantly increases the absorption of ivacaftor by 2 to 4 times compared to fasting conditions. The tablet should be swallowed whole and not chewed, crushed, or broken. Maintaining consistent 12-hour intervals between doses helps ensure stable drug levels in the blood.
The most common side effects include headache, upper respiratory tract infections (common cold, nasal congestion), abdominal pain, diarrhea, rash, nausea, and dizziness. Elevated liver enzymes (transaminases) are also common and require regular monitoring with blood tests. Most side effects are mild to moderate in severity. Contact your healthcare provider if any side effect becomes severe, persistent, or if you experience signs of liver problems such as yellowing of the skin, dark urine, or unexplained fatigue.
Ivacaftor is a highly lipophilic (fat-soluble) drug that is practically insoluble in water. When taken with fat-containing food, its oral bioavailability increases by approximately 2 to 4 times compared to fasting conditions, meaning significantly more of the drug reaches the bloodstream. This is because dietary fat stimulates bile acid secretion, which helps solubilize ivacaftor in the gastrointestinal tract and enhances its absorption. Examples of suitable fat-containing foods include eggs, avocado, nuts, butter, cheese, whole-milk yogurt, and peanut butter.
Ivacaftor Win Medica targets specific CFTR gating (Class III) mutations where the CFTR protein reaches the cell surface but does not open properly. The approved mutations include: G551D (the most common gating mutation, found in approximately 4–5% of all CF patients worldwide), G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, and S549R. Before starting treatment, a confirmed CF diagnosis with genotyping to identify the specific CFTR mutation is mandatory.
There is limited data on the use of ivacaftor in pregnant women. Animal studies have not shown harmful effects at clinically relevant doses, but as a precaution, Ivacaftor Win Medica should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. It is not known whether ivacaftor is excreted in human breast milk. A decision must be made whether to discontinue breastfeeding or therapy, considering the benefit of each. Discuss your individual situation with your healthcare provider.
References
- Ramsey BW, Davies J, McElvaney NG, et al. A CFTR potentiator in patients with cystic fibrosis and the G551D mutation. N Engl J Med. 2011;365(18):1663-1672. doi:10.1056/NEJMoa1105185
- Davies JC, Wainwright CE, Canny GJ, et al. Efficacy and safety of ivacaftor in patients aged 6 to 11 years with cystic fibrosis with a G551D mutation. Am J Respir Crit Care Med. 2013;187(11):1219-1225. doi:10.1164/rccm.201301-0153OC
- De Boeck K, Munck A, Walker S, et al. Efficacy and safety of ivacaftor in patients with cystic fibrosis and a non-G551D gating mutation. J Cyst Fibros. 2014;13(6):674-680. doi:10.1016/j.jcf.2014.09.005
- European Medicines Agency (EMA). Ivacaftor Summary of Product Characteristics (SmPC). EMA/CHMP. Updated 2025.
- U.S. Food and Drug Administration (FDA). Kalydeco (ivacaftor) prescribing information. Reference ID: 5208122. Updated 2025.
- Cystic Fibrosis Foundation. CFTR Modulator Therapies. Available at: cff.org. Accessed January 2026.
- European Cystic Fibrosis Society (ECFS). ECFS Standards of Care: Best Practice Guidelines. J Cyst Fibros. 2024;23(Suppl 1):S1-S42.
- Middleton PG, Mall MA, Drevinek P, et al. Elexacaftor-Tezacaftor-Ivacaftor for Cystic Fibrosis with a Single Phe508del Allele. N Engl J Med. 2019;381(19):1809-1819. doi:10.1056/NEJMoa1908639
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List, 2023. Geneva: World Health Organization; 2023.
- Flume PA, Liou TG, Borowitz DS, et al. Ivacaftor in subjects with cystic fibrosis who are homozygous for the F508del-CFTR mutation. Chest. 2012;142(3):718-724. doi:10.1378/chest.11-2672
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