Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jun 12;6(4):100207.
doi: 10.1016/j.acepjo.2025.100207. eCollection 2025 Aug.

Long-Term Clinical Outcomes of Rattlesnake Envenomation in Arizona Following Treatment With Crofab vs Anavip: A Retrospective Observational Study

Geoffrey T Smelski  1 , Anne Marie Guthrie  1 , David R Axon  2   3 , Farshad Mazda Shirazi  1   4 , Frank G Walter  1   4   5 , Charles J Gerardo  6
Affiliations

Long-Term Clinical Outcomes of Rattlesnake Envenomation in Arizona Following Treatment With Crofab vs Anavip: A Retrospective Observational Study

Geoffrey T Smelski et al. J Am Coll Emerg Physicians Open. .

Abstract

Objectives: The purpose of this study was to compare patient-reported outcomes regarding tissue injury caused by rattlesnake envenomation for patients treated with Crofab or Anavip.

Methods: We performed a chart review of the Arizona Poison and Drug Information Center's records from January 2017 through December 2021 for patients who received antivenom for rattlesnake envenomation. We present responses to standardized questions asked on days 7, 14, 90, and 180 regarding the presence of pain, edema, and functional impairment, with full recovery defined as the resolution of all 3.

Results: Patients treated with Crofab (n = 272) and Anavip (n = 241) were similar with regard to age, sex, bite location, and time to treatment. At each time point, the percentage of patients reporting resolution of pain, edema, or function was higher in patients treated with Crofab, when compared with those treated with Anavip. Clinically important differences in the percentage of patients reporting full recovery favoring Crofab were identified at 7 days (15.1% vs 6.6%, difference 8.5%, 95% CI: 3.1%-13.7%), 14 days (34.6% vs 24.9%, difference 9.7%, 95% CI: 1.8%-17.5%), and 90 days (60.3% vs 52.7%, difference 7.6%, 95% CI: -1.0% to 16.2%).

Conclusion: Following rattlesnake envenomation in Arizona, patients treated with Crofab had higher rates of full recovery from tissue injury than patients treated with Anavip at 7, 14, 90, and 180 days.

Keywords: antivenom; effectiveness; envenomation; rattlesnake; recovery.

PubMed Disclaimer

Conflict of interest statement

All authors have affirmed they have no conflicts of interest to declare.

Figures

Figure 1
Figure 1
Patient flowchart.
Figure 2
Figure 2
Resolution of pain, edema, and functional impairment following rattlesnake envenomation.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Greene S.C., Folt J., Wyatt K., Brandehoff N.P. Epidemiology of fatal snakebites in the United States 1989-2018. Am J Emerg Med. 2021;45:309–316. doi: 10.1016/j.ajem.2020.08.083. - DOI - PubMed
    1. Dart R.C., McNally J.T., Spaite D.W., et al. In: Biology of the Pitvipers. Selva. Campbell J.A., Brodie E.D. Jr., editors. 1992. The sequelae of pitviper poisoning in the United States; p. 395.
    1. Tupetz A., Phillips A.J., Kelly P.E., et al. Contextualizing the impact of snakebite envenoming on patients: a qualitative content analysis of patient-specific functional scale activities using the international classification of functioning, disability and health. Int J Environ Res Public Health. 2021;18(18):9608. doi: 10.3390/ijerph18189608. - DOI - PMC - PubMed
    1. Seifert S.A., Armitage J.O., Sanchez E.E. Snake envenomation. N Engl J Med. 2022;386(1):68–78. doi: 10.1056/NEJMra2105228. - DOI - PMC - PubMed
    1. Bittenbinder M.A., van Thiel J., Cardoso F.C., et al. Tissue damaging toxins in snake venoms: mechanisms of action, pathophysiology and treatment strategies. Commun Biol. 2024;7(1):358. doi: 10.1038/s42003-024-06019-6. - DOI - PMC - PubMed

LinkOut - more resources