Lorlatinib and Dabigatran: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lorlatinib
Dabigatran
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
Reduced dabigatran exposure, reduced efficacy of dabigatran and an increased risk of thrombosis
Interaction Deep Dive
Avoid concomitant use of dabigatran (a P-gp substrate) and a P-gp inducer as exposure of dabigatran is reduced. Concomitant use of a single dabigatran dose following 7 days of the P-gp inducer rifampicin 600 mg/day led to a decrease in mean dabigatran AUC and Cmax (66% and 67%, respectively) compared with dabigatran alone1. Trough dabigatran levels were undetectable in a patient receiving concomitant phenytoin and dabigatran 4 and another patient developed thrombosis on the combination 2. If concomitant use of a direct oral anticoagulant (DOAC) and an enzyme-inducing drug is necessary, monitoring of the DOAC concentration may be useful 3.
Why it happens (mechanism)
Induction of P-gp-mediated efflux transport of dabigatran
Literature reports
4 reports — tap to read
a) Trough dabigatran concentrations were undetectable in a 45-year-old man with atrial fibrillation who was receiving concomitant dabigatran 150 mg twice daily with phenytoin 100 mg 3 times daily. He was admitted to the hospital following defibrillations from his implantable cardioverter defibrillator, which was successfully treated. A suspected drug interaction between dabigatran and phenytoin led to a measurement of the serum concentration of dabigatran at 10 hours after the morning dose, upon which the undetectable levels were found. A recommendation was made to change either the patient's antiepileptic or anticoagulant drug agent 4.
b) Development of a thrombus in the left atrium was reported in a 70-year-old man receiving concomitant dabigatran 150 mg orally twice daily and phenytoin 300 mg/day orally. The patient had a history of seizures, hypertension, persistent atrial fibrillation, multiple DVTs, a pulmonary embolus, was heterozygous for factor V Leiden, and had an inferior vena cava filter. The patient had been receiving dabigatran for more than 1 year (previously treated with warfarin) and had restarted phenytoin after experiencing a seizure 4 weeks prior to the thrombus event. On hospital admission, serum phenytoin levels were 84 mcmol/L (therapeutic range, 40 to 80 mcmol/L) with an adjusted range of 32 to 64 mcmol/L based on an albumin level of 33 g/L. Adherence to medications was confirmed. Activated partial thromboplastin time was 36 seconds and the INR was 1.1. The patient was switched to enoxaparin subQ for 6 weeks then dabigatran was restarted. Phenytoin was slowly discontinued over 2 weeks while levetiracetam was started. The clot was resolved by 12 weeks. The Drug Interaction Probability Scale indicated a possible interaction 2.
c) In a retrospective study evaluating hospitalized patients who received concomitant direct oral anticoagulants (DOACs; apixaban, 77%; rivaroxaban, 15%; dabigatran, 8%) with an enzyme-inducing drug (total study population, 1596; 22 [1.4%] received the concomitant prescriptions), a DOAC concentration below the fifth percentile of expected concentration occurred in 6 of 11 patients who had measured DOAC levels. The DOACs were prescribed for atrial fibrillation (86%) or VTE (14%) and the indication for the enzyme inducer was primarily for seizure (55%), but also for neuropathy, essential tremor, or depression 3.
d) Concomitant use of a single dabigatran dose following 7 days of the P-gp inducer rifampicin 600 mg/day led to a decrease in mean dabigatran AUC and Cmax (66% and 67%, respectively) compared with dabigatran alone 1.
Common questions
Can I take Lorlatinib and Dabigatran together?
Reduced dabigatran exposure, reduced efficacy of dabigatran and an increased risk of thrombosis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lorlatinib and Dabigatran 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 Lorlatinib or Dabigatran 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 (4)
- Product Information: PRADAXA(R) oral capsules, dabigatran etexilate oral capsules. Boehringer Ingelheim Pharmaceuticals Inc (per FDA), Ridgefield, CT, 2023. DailyMed
- Hager N, Bolt J, Albers L, et al: Development of left atrial thrombus after coadministration of dabigatran etexilate and phenytoin. Can J Cardiol 2017; 33(4):554-554. PubMed
- Perlman A, Hochberg-Klein S, Choshen Cohen L, et al: Management strategies of the interaction between direct oral anticoagulant and drug-metabolizing enzyme inducers. J Thromb Thrombolysis 2019; 47(4):590-595. PubMed
- Wiggins BS, Northup A, Johnson D, et al: Reduced anticoagulant effect of dabigatran in a patient receiving concomitant phenytoin. Pharmacotherapy 2016; 36(2):e5-e7. DOI
Keep reading about Lorlatinib
Keep reading about Dabigatran
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