Medical Emergencies PA
Question
A teen with cystic fibrosis is starting ivacaftor/tezacaftor/elexacaftor. Which administration instruction is most important for proper absorption?
-
1
Take the medication on an empty stomach
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2
Crush the tablets to ease swallowing
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3
Take both AM and PM doses with fat-containing food to ensure absorption; do not consume grapefruit
✓ Correct answer
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4
Discontinue dornase alfa and airway clearance therapy
Explanation
Correct (2): CFTR modulators are lipophilic — bioavailability requires fat-containing food with each dose. Grapefruit/Seville orange inhibit CYP3A4 and increase drug levels — avoid. (1) Empty stomach reduces absorption ~80%. (3) Crushing not generally recommended. (4) Dornase alfa and airway clearance continue.
In-depth explanation
Memory Tip CFTR modulators (Trikafta·Kalydeco) = "Fat-required, Grapefruit-no." LFT monitoring required.
Clinical scenario
Scenario 16-year-old with cystic fibrosis (heterozygous F508del) starting elexacaftor/tezacaftor/ivacaftor (Trikafta) AM dose and ivacaftor PM dose. Outpatient teaching.
Key concepts
- CFTR modulator — Drugs correcting CFTR protein function in cystic fibrosis; ivacaftor, tezacaftor, elexacaftor, lumacaftor.
- Fat-containing food — Required for lipophilic drug absorption; standard counseling for CFTR modulators.
- CYP3A4 grapefruit interaction — Grapefruit inhibits CYP3A4, raising CFTR modulator levels; avoid.
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For study reference only. Always follow current clinical guidelines and your institution’s protocols.