Ceftriaxone Injection and Lansoprazole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ceftriaxone Injection
Lansoprazole
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 risk of ventricular arrhythmias
Interaction Deep Dive
Concomitant use of ceftriaxone and lansoprazole should be avoided as concomitant use may result in an increased risk of ventricular arrhythmias or cardiac arrest. For patients already receiving lansoprazole who are going to receive ceftriaxone, lansoprazole should be withheld or substituted with another proton pump inhibitor1.
Why it happens (mechanism)
Unknown
Literature reports
1 report — tap to read
a) A retrospective cohort study including adult medical inpatients receiving ceftriaxone with lansoprazole or another PPI was conducted from 2015 to 2021. Of the 31,152 patients hospitalized who were treated with ceftriaxone while receiving a PPI, 16,135 patients (51.8%) were male, and the mean (SD) age was 71.7 (16) years. The study included 3747 patients in the lansoprazole group and 27,405 patients in the other PPI group. Ventricular arrhythmia or cardiac arrest occurred significantly more often in the lansoprazole group compared with the other PPI group (3.4% vs 1.2%). In-hospital mortality occurred in 746 patients (19.9%) within the lansoprazole group and 2762 patients (10.1%) in the other PPI group. After weighting using propensity scores, the adjusted risk difference for the lansoprazole group minus other PPI group was 1.7% (95% CI, 1.1% to 2.3%) for ventricular arrhythmia or cardiac arrest and 7.4% (95% CI, 6.1% to 8.8%) for in-hospital mortality.1.
Common questions
Can I take Ceftriaxone Injection and Lansoprazole together?
Increased risk of ventricular arrhythmias Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ceftriaxone Injection and Lansoprazole 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Ceftriaxone Injection or Lansoprazole 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)
- Bai AD, Wilkinson A, Almufleh A, et al: Ceftriaxone and the risk of ventricular arrhythmia, cardiac arrest, and death among patients receiving lansoprazole. JAMA Netw Open 2023; 6(10):e2339893. PubMed
Keep reading about Ceftriaxone Injection
Keep reading about Lansoprazole
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