Semaglutide and Alectinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Alectinib
Semaglutide
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
Decreased alectinib exposure
Interaction Deep Dive
Concomitant administration of alectinib with SUBQ semaglutide may result in decreased alectinib exposure. Use caution when prescribing semaglutide, especially in alectinib dose-reduced patients; monitoring of alectinib plasma concentrations may be necessary. In a pharmacokinetic study (N=10) comparing alectinib exposure on alectinib monotherapy versus coadministration with SUBQ semaglutide, a significant reduction in mean AUC of 32% was seen observed with the coadministration of SUBQ semaglutide. Similar trends were seen with Ctrough and Cmax when alectinib was coadministered with SUBQ semaglutide1.
Why it happens (mechanism)
Induction of satiety and delayed gastric motility by semaglutide resulting in decreased alectinib absorption and exposure
Literature reports
1 report — tap to read
a) In a two-period (each lasting 1 week) cross-over study (N=10) comparing alectinib exposure on alectinib monotherapy (600 mg orally twice daily, period A) versus coadministration of SUBQ semaglutide 2 mg (period B) a geometric mean AUC(0 to 10 hr) of 7114 ng × hr/mL (coefficient of variation [CV], 34%) was observed with alectinib monotherapy, compared to an AUC(0 to 10 hr) of 4843 ng × hr/mL (CV, 47%) after coadministering alectinib with SUBQ semaglutide. This change in alectinib geometric mean AUC constituted a significant and clinically relevant reduction of 32% (95% CI, -45% to -15%) when coadministering semaglutide. Additionally, trough concentrations (Ctrough) showed a similar trend towards lower concentrations with semaglutide, decreasing the geometric mean Ctrough from 681 ng/mL (CV, 29%) to 509 ng/mL (CV, 66%), reflecting a relative difference of -25% (95% CI, -46% to 3%) when alectinib was combined with semaglutide compared to alectinib alone. The maximum concentration (Cmax) decreased with 36% (95% CI, -48% to -20%) with a Cmax of alectinib of 875 ng/mL (CV, 31%) on monotherapy versus 563 ng/mL (CV, 42%) in the combination arm. In addition, during alectinib monotherapy, all patients had Ctrough levels surpassing the efficacy threshold (ie, greater than 435 ng/mL), while only 60% (n=6) retained plasma Ctrough levels with the combination of alectinib and semaglutide. The 4 patients that did not retain therapeutic Ctrough levels were receiving reduced dose alectinib (450 mg orally twice daily) 1.
Common questions
Can I take Semaglutide and Alectinib together?
Decreased alectinib exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Semaglutide and Alectinib interaction?
It is rated moderate. Can be significant — usually manageable with 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Semaglutide or Alectinib 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 anything you'd monitor while I'm on both?
References (1)
- Heersche N, Lanser DAC, Oomen-de Hoop E, et al: Semaglutide impairs bioavailability of alectinib: a note of warning based on a cross-over pharmacokinetic drug-drug interaction study. Cancer Commun (Lond) 2025; Epub:Epub. DOI
Keep reading about Alectinib
Keep reading about Semaglutide
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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