A prospective series of acute rivaroxaban overdose, coagulopathy and bleeding complications (ATOM 11).

AIM: There is limited research describing rivaroxaban overdose. We aim to describe rivaroxaban overdose, coagulopathy and bleeding complications.

METHODS

This is a prospective series of acute adult (>14 years) rivaroxaban overdose presentations >40 mg enrolled in the Australian Toxicology Monitoring study and presenting to three Australian clinical toxicology units from August 2014 to August 2024. Data collected included demographics, ingestion details, coagulation profile, rivaroxaban concentrations, significant bleeding (with haemoglobin decrement) and outcome.

RESULTS

There were 58 presentations in 52 patients, 29/52 (56%) males, median age of 49 years (range: 18-93 years). The median reported dose ingested was 200 mg (IQR: 92.5-400 mg, range: 45-1120 mg). Co-ingestants were taken in 49 (84%), most commonly mirtazapine and paracetamol. A raised international normalized ratio (INR) of >1.5 occurred in 46 (79%) with a median peak INR of 2.5 (IQR: 1.7-3.7). The median duration for an elevated INR to return to ≤1.5 was 22 h (IQR: 14-38 h). Significant bleeding occurred in two patients; both were managed conservatively without factor replacement. Rivaroxaban concentrations were available in 11 cases. There was a strong correlation (R2 = 0.83, p < .001) between rivaroxaban concentration and INR. An INR of ≤1.5 was associated with therapeutic rivaroxaban concentrations. There was one death attributed to co-ingested amlodipine.

CONCLUSION

Bleeding was uncommon following rivaroxaban overdose. The INR appears to be a good indicator of coagulopathy, with an INR of ≤1.5 approximating therapeutic rivaroxaban concentrations. Observation of patients following acute rivaroxaban overdose until the INR ≤ 1.5 seems reasonable.