Tezacaftor and Lenacapavir Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lenacapavir Injection
Tezacaftor
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased tezacaftor exposure and an increased risk tezacaftor-related adverse reaction
Interaction Deep Dive
Concomitant administration of tezacaftor-containing products and a moderate CYP3A inhibitor may increase tezacaftor exposure. Reduce the tezacaftor dosage with concomitant use. For 6 to less than 12 years old, patients weighing less than 40 kg adjust the dose to two tablets of vanzacaftor 4 mg/tezacaftor 20 mg/deutivacaftor 50 mg every other day and for patients greater than or equal to 40 kg adjust the dose to one tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg every other day. For 12 years and older patients adjust the dose to one tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg every other day1. For tezacaftor/ivacaftor, alternate daily dosing starting with tezacaftor 100 mg/ivacaftor 150 mg orally in the morning on day 1, then ivacaftor 150 mg orally in the morning on day 2 (do not take any ivacaftor evening doses). Continue alternating these morning doses during concomitant therapy 3. For elexacaftor/tezacaftor/ivacaftor, alternate daily dosing starting with 2 tablets (elexacaftor 100 mg/tezacaftor 50 mg/ivacaftor 75 mg per tablet) orally in the morning on day 1, then ivacaftor 150 mg orally in the morning on day 2 (do not take any ivacaftor evening doses). Continue alternating these morning doses during concomitant therapy 2.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of tezacaftor
Literature reports
3 reports — tap to read
a) Dose simulation studies suggested that tezacaftor exposure may be increased by 2-fold 32.
b) Coadministration of ivacaftor 150 mg orally twice daily with moderate CYP3A inhibitor fluconazole 400 mg orally x 1 dose on day 1, followed by 200 mg once daily resulted in a 2.95-fold increase in ivacaftor exposure and a 2.47-fold increase in Cmax 32.
c) In a drug interaction study, coadministration of vanzacaftor 20 mg, tezacaftor 100 mg and deutivacaftor 250 mg once daily with moderate CYP3A inhibitor fluconazole 200 mg daily resulted in increased vanzacaftor AUC by 2.55-fold and Cmax by 2.48-fold, it also increased deutivacaftor AUC by 3.13-fold and Cmax by 2.27-fold 1.
Common questions
Can I take Tezacaftor and Lenacapavir Injection together?
Increased tezacaftor exposure and an increased risk tezacaftor-related adverse reaction Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tezacaftor and Lenacapavir Injection interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Tezacaftor or Lenacapavir Injection need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: ALYFTREK(R) oral tablets, vanzacaftor, tezacaftor, and deutivacaftor oral tablets. Vertex Pharmaceuticals Incorporated (per FDA), Boston, MA, 2024. DailyMed
- Product Information: TRIKAFTA(R) oral tablets oral granules, elexacaftor, tezacaftor, ivacaftor oral tablets oral granules; ivacaftor oral tablets oral granules. Vertex Pharmaceuticals Incorporated (per FDA), Boston, MA, 2024. DailyMed
- Product Information: SYMDEKO(TM) oral tablets, tezacaftor ivacaftor oral tablets and ivacaftor oral tablets. Vertex Pharmaceuticals Incorporated (per manufacturer), Boston, MA, 2019. DailyMed
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