Introduction Snakebite envenoming (SBE) results in over 500 000 deaths or disabling injuries annually. Varespladib methyl, an oral inhibitor of secretory phospholipase A2, is a nearly ubiquitous component of snake venoms. We conducted a phase II clinical trial to assess efficacy and safety of oral varespladib methyl in patients bitten by venomous snakes. Methods This double-blind, randomised, placebo-controlled trial enrolled patients in emergency departments in India and the USA. Patients with SBE were randomly assigned (1:1) to receive varespladib methyl or placebo two times per day for 1 week. All patients received standard of care, including antivenom. The primary outcome was change in the composite Snakebite Severity Score (SSS) measuring the severity of envenoming, from baseline to the average composite SSS at 6 and 9 hours. Results Among 95 patients randomised August 2021 through November 2022, the most common snakebites were from Russell’s vipers (n=29), copperheads (n=18) and rattlesnakes (n=14). The SSS improved from baseline to the average at 6 and 9 hours by 1.1 (95% CI, 0.7 to 1.6) in the varespladib group versus 1.5 (95% CI, 1.0 to 2.0) in the placebo group (difference −0.4, 95% CI, −0.8 to 0.1, p=0.13). While key secondary outcomes were not statistically different by treatment group, benefit was seen in the prespecified subgroup initiating study drug within 5 hours of bite (n=37). For this early treatment group, clinically important differences were observed for illness severity over the first week, patient-reported function on days 3 and 7 and complete recovery. No death or treatment emergent serious adverse event occurred. Conclusion For emergency department treatment of snakebites, the addition of varespladib to antivenom did not find evidence of difference for the primary outcome based on the SSS. A potentially promising signal of benefit was observed in patients initiating treatment within 5 hours of snakebite.

Methamphetamine (MA) toxicity is a major health concern causing agitation, hyperkinesia, hyperthermia, and even death, affecting 24.7 million people worldwide. It has been observed that MA generates movement disorders in children similar to that of scorpion envenomation. Four cases have been reported where MA intoxication in children were both subjectively and objectively improved as indicated by the reversal of nystagmus and movement disorders following administration of Centruroides antivenom (AV) therapy. Here, we aimed to demonstrate the reversal of MA induced movement disorders and hyperthermia by scorpion AV equine immune F(ab’)2 in rats. Baseline core temperature and locomotor activity in adult male Sprague-Dawley rats (200–220 g) were evaluated prior to acute administration of AV (20 mg/kg, intraperitoneally, i.p.) + MA (10 mg/kg, i.p.) or control. Core body temperature was reassessed 10, 50, and 80 min post injection while locomotor activity was reassessed 20–35 and 60–75 min post injection. At 20–35 min, Saline + MA and BSA + MA groups showed a significant increase in the number of fine events compared to their respective control groups Saline + Saline and BSA + Saline, which indicates an increase in paw movements of animals in situ (p = 0.008, p = 0.006, respectively). In contrast, AV + MA demonstrated a non-significant increase in fine activity compared to the control group AV + Saline). At 60–75 min, the AV + MA treatment group were less likely to engage in locomotor activity indicated by the significant decrease in exploratory events compared to BSA + MA control group (p = 0.041). No significant percent change in core body temperature was observed in the AV + MA treatment group compared to the control groups, AV + Saline and BSA + MA. Here, we provide evidence for some aspects of MA-induced hyperkinesia but not hyperthermia reversed by scorpion AV. Further preclinical studies involving adolescent rodents may be necessary to completely mimic the reversal of MA toxicity seen in children in the clinic.

Neurotoxic envenomation by rattlesnakes has been of great concern throughout the Americas and in Arizona. In addition to clinical weakness, patients sometimes display myokymia, a disordered fasciculation of skeletal muscle, which is mediated by Mojave toxin. As neurotoxic venoms have been associated with increased release of creatine kinase (CK) activity and concordant increases in length of stay (LOS) in the hospital, it was retrospectively determined if point-of-care ultrasound detected myokymia at the bite site was associated with increased CK activity, LOS, and healthcare cost compared to rattlesnake envenomations not associated with myokymia. The Arizona Poison and Drug Information Center patient database was queried for patients with point-of-care ultrasound exam results at or near the bite site from 2017 to 2021. Using point-of-care ultrasound to detect subclinical myokymia, thirty-seven patients that met inclusion criteria were determined to have myokymia (n = 16) and/or not display it (n = 21). Patients with myokymia had twice the CK activities, double the LOS, and two-fold the healthcare costs of patients without myokymia detected. These findings serve as a rationale for future investigations to link ultrasound detected myokymia with patient outcomes.