Kalydeco (ivacaftor) for Cystic Fibrosis: Side Effects & Dosage

Generic drug: ivacaftor

Brand name: Kalydeco

What is Kalydeco (ivacaftor), and how does it work?

Kalydeco (ivacaftor) is a prescription medicine used for the treatment of cystic fibrosis (CF) in patients age 6 months and older who have at least one mutation in their CF gene that is responsive to Kalydeco.

Talk to your doctor to learn if you have an indicated CF gene mutation.

It is not known if Kalydeco is safe and effective in children under 6 months of age.

What are the side effects of Kalydeco?

Kalydeco can cause serious side effects.

High liver enzymes in the blood have been reported in patients receiving
Kalydeco. Your doctor will do blood tests to check your liver:

before you start Kalydeco
every 3 months during your first year of
taking Kalydeco
every year while you are taking Kalydeco

For patients who have had high liver enzymes in the past, the doctor may do blood tests to check the liver more often.

Call your doctor right away if you have any of the following symptoms of liver problems:

pain or discomfort in the upper right stomach (abdominal) area
yellowing of your skin or the white part of your eyes
loss of appetite
nausea or vomiting
dark, amber-colored urine

Abnormality of the eye lens (cataract) has been noted in some children and adolescents receiving
Kalydeco.

Your doctor should perform eye examinations prior to and during treatment with
Kalydeco to look for cataracts.

The most common side effects of Kalydeco include:

headache
upper respiratory tract infection (common cold), including:
- sore throat
- nasal or sinus congestion
- runny nose
stomach (abdominal) pain
diarrhea
rash
nausea
dizziness

Tell your doctor if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of
Kalydeco. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the dosage for Kalydeco?

General Dosing Information

Kalydeco should be taken with
fat-containing food. Examples include eggs, butter, peanut butter, cheese pizza,
whole-milk dairy products (such as whole milk, cheese, yogurt, breast milk or
infant formula), etc.

Recommended Dosage In Adults And Pediatric Patients Aged 6 Years And Older

The recommended dosage of
Kalydeco for adults and pediatric patients ages 6 years and older is one 150 mg
tablet taken orally every 12 hours (300 mg total daily dose) with fat-containing
food.

Recommended Dosage In Pediatric Patients Aged 4 Months To Less Than 6 Years

The recommended dosage of
Kalydeco (oral granules) for patients ages 4 months to less than 6 years is weight-based according to Table 1.

Table 1: Dosage of
Kalydeco Oral Granules by Body Weight in Pediatric Patients Ages 4 months to less than 6 Years

AgeBody Weight (kg)
Kalydeco DosageTotal Daily Dose4 months* to less than 6 months⁺5 kg or greaterOne 25 mg packet every 12 hours50 mg/day6 months or older5 kg to less than 7 kgOne 25 mg packet every 12 hours50 mg/day7 kg to less than 14 kgOne 50 mg packet every 12 hours100 mg/day14 kg or greaterOne 75 mg packet every 12 hours150 mg/day*Kalydeco is not recommended for use in children under 4 months of age.
⁺Kalydeco is not recommended for use in children aged 4 months to less than 6 months with hepatic impairment and/or taking concomitant moderate or strong CYP3A inhibitors

Instructions For Administration Of Oral Granules

The entire contents of each packet of oral granules should be mixed with one teaspoon (5 mL) of age-appropriate soft food or liquid and completely consumed.
Food or liquid should be at or below room temperature.
Once mixed, the product has been shown to be stable for one hour, and therefore should be consumed during this period.
Some examples of soft foods or liquids may include puréed fruits or vegetables, yogurt, applesauce, water, breast milk, infant formula, milk, or juice.
Each dose should be administered just before or just after fat-containing food [see
General Dosing Information above].

Dosage Adjustment For Patients With Hepatic Impairment Aged 6 Months And Older

The dosage of Kalydeco should be reduced to one tablet or one packet of oral granules once daily for patients aged 6 months and older with moderate hepatic impairment (Child-Pugh Class B).
Kalydeco should be used with caution in patients aged 6 months and older with severe hepatic impairment (Child-Pugh Class C), at a dosage of one tablet or one packet of oral granules once daily or less frequently.
Use is not recommended in patients with hepatic impairment below 6
months of age.

Dosage Adjustment For Patients Aged 6 Months And Older Taking Drugs That Are CYP3A Inhibitors

When Kalydeco is being co-administered with strong CYP3A inhibitors (e.g., ketoconazole) in patients aged 6 months or older, the dose should be reduced to one tablet or one packet of oral granules twice a week.
The dose of Kalydeco should be reduced to one tablet or one packet of
granules once daily when co-administered with moderate CYP3A inhibitors
(e.g., fluconazole).
Concomitant use of moderate or strong CYP3A inhibitors is not
recommended in patients below 6 months of age.
Food containing grapefruit should be avoided.

What drugs interact with Kalydeco?

Potential For Other Drugs To Affect Ivacaftor

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 dose
is recommended for patients taking concomitant strong CYP3A inhibitors, such
as ketoconazole, itraconazole, posaconazole, voriconazole, telithromycin,
and clarithromycin.
Co-administration with fluconazole, a moderate inhibitor of CYP3A, increased ivacaftor exposure by 3-fold.
Therefore, a reduction of the Kalydeco dose is recommended for patients
taking concomitant moderate CYP3A inhibitors, such as fluconazole and
erythromycin.
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 containing grapefruit during treatment with
Kalydeco.

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.

Ciprofloxacin

Co-administration of Kalydeco with ciprofloxacin had no effect on the exposure of ivacaftor.
Therefore, no dose adjustment is necessary during concomitant administration of
Kalydeco with ciprofloxacin.

Potential For Ivacaftor To Affect Other Drugs

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.

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.

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Is Kalydeco safe to use while pregnant or breastfeeding?

There are limited and incomplete human data from clinical trials and post marketing reports on use of
Kalydeco in pregnant women.
There is no information regarding the presence of ivacaftor in human milk, the effects on the breastfed infant, or the effects on milk production.
The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for
Kalydeco, and any potential adverse effects on the breastfed child from
Kalydeco or from the underlying maternal condition.