Nonsteroidal Anti-Inflammatory Drugs Are Safe and Appropriate for the Treatment of Copperhead Envenomations

To the Editor:

We read with interest the recent study by Buchanan and colleagues regarding snakebites reported to the Kentucky Regional Poison Control Center. ¹ While we appreciate their important contribution to the medical literature on snake envenomation, we believe that certain points raised in their manuscript require clarification.

Buchanan and colleagues state that “use of non-steroidal anti-inflammatory drugs [NSAIDs] should be avoided for pain control in favor of opiates because they may potentiate venom’s effects on platelet aggregation and coagulation.” They do acknowledge that there is “little evidence to suggest [NSAIDs] should be avoided in copperhead bites,” but consistently classify aspirin and NSAIDs as “contraindicated therapies” in their text and in Table 3.

There is in fact good evidence that NSAIDs are safe in patients suffering copperhead envenomation. A retrospective cohort study of 147 patients with copperhead envenomation treated in Missouri found that there was no significant difference in coagulation parameters between patients tread with NSAIDs and patients treated without NSAIDs; additionally, there were no bleeding events attributable to NSAID therapy. ² This finding has been confirmed by secondary retrospective analysis of large clinical trials. ³ This is likely because copperhead envenomation generally does not produce clinically significant or severe coagulopathy, as has been demonstrated in multiple studies in many regions of the United States using both conventional coagulation tests ^{4 -}7 and thromboelastograpy. ⁸ When perturbations in coagulation parameters do occur, they are typically mild^5,9 and not associated with bleeding. ⁵

The existing evidence is of course limited by the retrospective nature of the available studies as well as potential limitations in follow-up and definitive identification of envenomating species. Nevertheless, we are not aware of any published cases of medically significant bleeding following the use of NSAIDs to treat patients with copperhead envenomation.

We routinely use NSAIDs in the treatment of pediatric and adult patients with copperhead envenomations and have found the practice safe and effective. We agree that many patients with copperhead envenomation may benefit from opioid therapy, but find that NSAIDs are generally opioid-sparing, and may completely control pain in some cases. Although it remains appropriate to avoid NSAIDs in patients with rattlesnake envenomations, given the high rates of associated significant coagulopathy, ⁹ we believe that NSAID therapy is safe and appropriate in patients with copperhead envenomations.