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  2. North America
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  4. Pit Vipers
  5. Clinical entry: Agkistrodon sp. (USA)

Clinic: Agkistrodon sp. (USA)

Examine for venom effects

Autopharmacological effects

  • Nausea, vomiting
  • Sweating
  • Urticaria, angiooedema
  • Generalized oedema
  • Arterial hypotension / hypovolaemic shock (transient, recurrent)
  • Diarrhoea
  • Bronchospasm 

Local Effects

  • Pain
  • Tender local (spreading) swelling
  • Blistering
  • Lymphangiopathy and lymphadenopathy
  • Necrotic skin; can include muscle locally.

Haematological effects 

  • Bleeding from the fang marks and from injuries, in particular ones that are not located in the region in which venom application occurred.
  • Bleeding into the skin (ecchymosis, petechiae)
  • Gingival bleeding, bleeding from the nose, conjunctiva, haematemeis, bleeding per rectum, including melaena, haematuria, haemoptysis.

Species-specific envenoming pattern

The assessment of the envenoming pattern is based on the data from publication in which the identification of the snakes is clearly specified and in accordance with accepted criteria.

   Autopharma-
cological
effects1		 Local
effects2
 		 Haematological effects
 Bleeding3  Coagulopathy4 
Agkistrodon contortrix        
Agkistrodon piscivorus        

1Autopharmacological effects

Nausea, vomiting, art. hypotension, hypotensive shock.

The observation of Ruha et al. (2025) underpins bradykinin driven toxicity potentiated by ACEIs in the patient envenomend by Agkistriodon contortrix and on ACEIs (Naasz et al. 2025) as argued by the authors. 

2Local effect

Local pain, erythema, ecchymosis, oedema, regional swelling, tender regional lymph nodes.

Hematological effects

3Bleeding

In very rare cases of severe envenoming.

4Coagulopathy

Type of haemostatic defect

The coagulation-promoting components of the A. contortrix venom generally appear not to cause clinically relevant haemostatic defects. 

Clinical management

See also Clinical Management: North America

for advice on post-First Aid measures, diagnosis (clinical, laboratory) and treatment (supportive, antivenom).

General 

If a bite is positively identified as a copperhead or water moccasin patients experience in most cases only local signs and symproms or mild forms of systemic envenoming requiring only symptomatic treatment and no antivenom (see experiences in 3 states: Baumgartner et al. (2019) - Missouri, Walker et al. (2011) - East Texas and Wittler et al. (2025) - North Carolina).
There are, however, though rarely, severe, life-threating forms of envenoming (Naasz et al. 2025) requiring ICU and antivenom treatment.
Agkistrodon sp. envenomend patients are, therfore, included in a management algorithm covering all North American crotalids, i.e. rattlesnakes, copperheads and water moccasins (see Lavonas et al. (2011); "Emergency Department and Hospital Management of Pit Viper Snakebite, Includes: Rattlesnakes, Copperheads, and Cottonmouths (Water Moccasins), Unified Treatment Algorithm for the Management of Pit Viper Snakebite in the United States."
The "Medical Society Clinical Practice Guidelines for the Treatment of Pit Viper Envenomations in the United States and Canada: 2026 Update" (Brandehoff et al. 2025) follows tthe same strategy; also Green et al. (2021), Warpinski et al. (2022), Yu et al (2024).
An additional important argument for this stratgey is that very often the culprit goes unidentified or is misidentified. 

First Aid

Release of any type of tourniquet follow link above.

Local treatment

Pain control
Tetanus prophylaxis
Standard wound care
Necroses: debridement; split-thickness skin grafting
Systemic antibiotics: standard indications
WHO (2010) 

Systemic supportive treatment

A general understanding of emergency medicine is required, or can be found in emergency medicine guidelines, e.g. ABCDE approach, WHO-ICRC Basic Emergency Care.

Follow SAMPLE & ABCDE ApproAch

Obey Agkistrodon sp. - specific features

see

  • 'Species-specific envenoming pattern above'

and

  • Evidence-informed unified treatment algorithm for pit viper snakebite management in the US (Lavonas et al. 2011)
  • Brandehoff et al. (2026)

Specific treatment (antivenoms)

 References

  • Baumgartner KT, Fishburn SJ, Mullins ME. Current Management of Copperhead Snakebites in Missouri. Mo Med. 2019 May-Jun;116(3):201-205. PMID: 31527942; PMCID: PMC6690278. 
  • Brandehoff N, Greene S, Benjamin J, et al. Wilderness Medical Society Clinical Practice Guidelines for the Treatment of Pit Viper Envenomations in the United States and Canada: 2026 Update.
  • Greene S, Cheng D, Vilke GM, Winkler G. How Should Native Crotalid Envenomation Be Managed in the Emergency Department? J Emerg Med. 2021 Jul;61(1):41-48. Epub 2021 Feb 20. PMID: 33622584. https://doi.org/10.1016/j.jemermed.2021.01.020
  • Lavonas, E.J., Ruha, AM., Banner, W. et al. Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop. BMC Emerg Med 11, 2 (2011). https://doi.org/10.1186/1471-227X-11-2
  • Naasz H, Cantillo-Campos S, Steinbock K, Godfrey AW, Gerardo CJ. A case of severe systemic copperhead (Agkistrodon contortrix) envenomation with shock. Toxicon. 2025 Jun;260:108361.  Epub 2025 Apr 16. PMID: 40250731. https://doi.org/10.1016/j.toxicon.2025.108361
  • Ruha AM, Spyres MB, Culbreth R, Wolk B, Hoyte C, Campleman S; ACMT ToxIC Snakebite Study Group. Systemic toxicity after rattlesnake envenomation in patients using angiotensin converting enzyme inhibitors: A North American Snakebite Registry study. Toxicon. 2025 Apr;258:108292.  Epub 2025 Mar 5. PMID: 40054781. https://doi.org/10.1016/j.toxicon.2025.108292
  • Walker JP, Morrison RL. Current management of copperhead snakebite. J Am Coll Surg. 2011 Apr;212(4):470-4; discussion 474-5. PMID: 21463771. https://doi.org/10.1016/j.jamcollsurg.2010.12.049

  • Warpinski GP, Ruha AM. North American Envenomation Syndromes. Emerg Med Clin North Am. 2022 May;40(2):313-326. PMID: 35461625. https://doi.org/10.1016/j.emc.2022.01.006

  • Wittler MA, Hiestand B, Bantikassegn A, Cline DM, Hannum JL. Outcomes of Copperhead Snake Envenomation Managed in a Clinical Decision Unit. West J Emerg Med. 2025 Jul 9;26(4):1062-1069. PMID: 40794975; PMCID: PMC12342414. https://doi.org/10.5811/westjem.20369

  • Yu E, Altschuh L. Clinical Management of North American Snake and Marine Envenomations. Emerg Med Clin North Am. 2024 Aug;42(3):653-666. Epub 2024 Mar 19. PMID: 38925780. https://doi.org/10.1016/j.emc.2024.02.020

Species-specific evidence

Agkistrodon sp.

  • Baumgartner et al. (2019) - Missouri
  • Walker et al. (2011) - East Texas
  • Wittler et al. (2025) - North Carolina

 Experience with Agkistrodon sp. envenoming across three states.

Agkistrodon contortrix

  • Naasz et al. (2025)
    1 patient (with multimorbidity); identification: morphological

References

  • Baumgartner KT, Fishburn SJ, Mullins ME. Current Management of Copperhead Snakebites in Missouri. Mo Med. 2019 May-Jun;116(3):201-205. PMID: 31527942; PMCID: PMC6690278.
  • Naasz H, Cantillo-Campos S, Steinbock K, Godfrey AW, Gerardo CJ. A case of severe systemic copperhead (Agkistrodon contortrix) envenomation with shock. Toxicon. 2025 Jun;260:108361.  Epub 2025 Apr 16. PMID: 40250731. https://doi.org/10.1016/j.toxicon.2025.108361
  • Walker JP, Morrison RL. Current management of copperhead snakebite. J Am Coll Surg. 2011 Apr;212(4):470-4; discussion 474-5. PMID: 21463771. https://doi.org/10.1016/j.jamcollsurg.2010.12.049
  • Wittler MA, Hiestand B, Bantikassegn A, Cline DM, Hannum JL. Outcomes of Copperhead Snake Envenomation Managed in a Clinical Decision Unit. West J Emerg Med. 2025 Jul 9;26(4):1062-1069. PMID: 40794975; PMCID: PMC12342414. https://doi.org/10.5811/westjem.20369