Reteplase, Recombinant and Lecanemab-Irmb Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lecanemab-Irmb Injection
Reteplase, Recombinant
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
An increased risk of amyloid related imaging abnormalities or intracerebral hemorrhage
Interaction Deep Dive
Exercise caution when considering the use of lecanemab-irmb in patients with factors that indicate an increased risk for intracerebral hemorrhage, or patients with findings on MRI that are suggestive of cerebral amyloid angiopathy. Exert additional caution with concomitant use of lecanemab-irmb and a thrombolytic agent (eg, tissue plasminogen activator), as it may increase the risk of amyloid related imaging abnormalities (ARIA) or intracerebral hemorrhage, because amyloid related imaging abnormalities with edema (ARIA-E) can cause focal neurologic deficits that can mimic an ischemic stroke. Consider whether such symptoms may be due to ARIA-E before giving thrombolytic therapy in a patient being treated with lecanemab-irmb. Fatal cerebral hemorrhage has occurred in a patient taking an anti-amyloid monoclonal antibody in the setting of focal neurologic symptoms of ARIA and the use of a thrombolytic agent2. Patients on lecanemab-irmb should not be treated with acute thrombolytics (IV or intraarterial) until evidence regarding safety of coadministration is available 1.
Why it happens (mechanism)
Additive effects on bleeding
Literature reports
2 reports — tap to read
a) Fatal cerebral hemorrhage has occurred in a patient taking an anti-amyloid monoclonal antibody in the setting of focal neurologic symptoms of ARIA and the use of a thrombolytic agent 2.
b) Fatal cerebral hemorrhage occurred after receiving alteplase in a 65-year-old patient with cognitive decline presenting to the emergency department with ischemic stroke and a history of receiving 3 lecanemab-irmb infusions, the last of which occurred 4 days prior to the stroke. Mild small-vessel disease but no microhemorrhages, edema, or amyloid-related imaging abnormalities were noted on MRI 81 days prior to the stroke, and CT prior to alteplase administration demonstrated hypodensities in the left temporal-parietal regions and a distal left middle cerebral artery branch occlusion but no hemorrhage. Since the patient had no contraindications to thrombolysis, alteplase 8 mg IV bolus was given with infusion initiated afterwards; however, hypertension developed 50 minutes into the infusion, which was then stopped. CT showed extensive multifocal intraparenchymal hemorrhages, and the patient had global aphasia, severe agitation, and frequent, nonconvulsive seizures on EEG. Three days after presentation, the patient was intubated and MRI showed acute right thalamocapsular infarction and innumerable multifocal cortical and subcortical hemorrhages with surrounding edema; the patient was given comfort care and later died. Autopsy demonstrated extensive multifocal intraparenchymal hemorrhages, cerebral amyloid angiopathy, Alzheimer’s disease neuropathologic changes, and diffuse histiocytic vasculitis with necrotizing vasculopathy involving amyloid deposition within the blood vessel walls. The authors note that the substantial number and variation in size of the cerebral hemorrhages is not a common complication of alteplase, and describe the possibility that lecanemab-irmb may have contributed to this adverse outcome 3.
Common questions
Can I take Reteplase, Recombinant and Lecanemab-Irmb Injection together?
An increased risk of amyloid related imaging abnormalities or intracerebral hemorrhage Always confirm with your pharmacist or prescriber before making any change.
How serious is the Reteplase, Recombinant and Lecanemab-Irmb 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Reteplase, Recombinant or Lecanemab-Irmb 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)
- Cummings J, Apostolova L, Rabinovici GD, et al: Lecanemab: appropriate use recommendations. J Prev Alzheimers Dis 2023; 10(3):362-377. PubMed
- Product Information: LEQEMBI(R) intravenous injection, lecanemab-irmb intravenous injection. Eisai Inc (per FDA), Nutley, NJ, 2025. DailyMed
- Reish NJ, Jamshidi P, Stamm B, et al: Multiple cerebral hemorrhages in a patient receiving lecanemab and treated with t-PA for stroke. N Engl J Med 2023; 388(5):478-479. PubMed
Keep reading about Lecanemab-Irmb Injection
Keep reading about Reteplase, Recombinant
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist