Systemic Toxicity after Rattlesnake Envenomation in Patients Using Angiotensin Converting Enzyme Inhibitors: A North American Snakebite Registry Study.

BACKGROUND: Some North American rattlesnake venoms and angiotensin converting enzyme inhibitor (ACEI) medications each increase bradykinin levels in humans, with clinical effects attributable to bradykinin described in exposed populations. Influence of ACEI exposure on persons with snake envenomation has not been studied. We used data from the ACMT North American Snakebite Registry (NASBR) to determine if use of ACEI medications at the time of rattlesnake envenomation is associated with increased rate of systemic toxicity. METHODS: Rattlesnake envenomations entered in the NASBR between January 1, 2013 and December 31, 2021 were included. Data extracted included patient demographics, medical history, clinical and laboratory findings, treatments, and outcomes. Patients who use ACE Inhibitors (ACEI group) were compared to patients without ACEI use (No ACEI group). Primary outcomes included systemic venom effects and secondary outcomes included length of stay and total number of antivenom vials administered (for Fab and F(ab')2). RESULTS: 817 rattlesnake envenomations were included. Forty-three (5.3%) were in the ACEI group and 774 (94.7%) in the No ACEI group. There were no differences in time to antivenom or acute hypersensitivity reactions between groups. Hypotension was more frequent in the ACEI group (18.6%) compared to the No ACEI group (6.5%; p=0.008). Diarrhea also occurred more frequently in the ACEI group (11.6%) compared to the No ACEI group (2.1%; p=0.003). However, overall systemic toxicity did not significantly differ between the two groups (25.6% ACEI vs. 17.4% no ACEI, p=0.25). CONCLUSIONS: In the NASBR, patients who use ACEIs are more likely to experience hypotension and/or diarrhea after rattlesnake envenomation than are patients who do not use ACEIs; however, overall systemic toxicity did not significantly differ between the two groups.