Bleeding After Rattlesnake Bites in Anticoagulated Patients

Ali S. Raja, MD, MBA, MPH, FACEP

Major bleeding following a rattlesnake envenomation was more likely in patients taking anticoagulants and antiplatelet agents.

Clinically significant bleeding following rattlesnake envenomation has been rare. However, many people are now on antiplatelet and anticoagulant medications, and whether they are more likely to bleed after being bitten is not known. Researchers in Arizona reviewed the records of 319 patients older than 14 years who had sustained rattlesnake envenomations to compare hospital courses and long-term outcomes between 31 patients (10%) who reported daily use of aspirin, clopidogrel, warfarin, or a combination of these drugs and 288 who were not using these medications.

Among patients for whom follow-up data were available, major bleeding occurred in 18% of the medication group versus 2% of the no-medication group (relative risk, 12.2). Nine patients also had late bleeding after discharge from the hospital, including three patients on the medications and six patients not on them. The composite endpoint of major bleeding, shock, readmission, or death was reached in 19% of patients on the medications versus 5% not on the medications (RR, 4.0).

Citation(s):

Levine M et al. Bleeding following rattlesnake envenomation in patients with preenvenomation use of antiplatelet or anticoagulant medications. Acad Emerg Med 2014 Mar; 21:301.