Low-dose versus standard-dose antivenom for neuroparalytic krait envenomation: a randomized pilot study

The common krait (Bungarus caeruleus) is a leading cause of neuroparalytic snake envenomation in South Asia. Current guidelines recommend escalation from 10 to 20 vials of polyvalent antivenom if neurotoxicity persists, despite limited evidence supporting this strategy.

This open-label, randomized pilot study was conducted in North India, enrolling patients with krait envenomation who presented with neurotoxic paralysis but without respiratory failure. Patients were assigned to receive either 10 vials or 20 vials of polyvalent antivenom. The primary outcome was time to recovery from neurotoxic paralysis. Secondary outcomes included the need for invasive mechanical ventilation, time from enrolment to intubation, duration of mechanical ventilation, and in-hospital mortality.

Of 97 patients screened, 53 underwent randomization (26 assigned to the 10-vial group and 27 to the 20-vial group). Baseline characteristics, severity of neurotoxic paralysis, laboratory parameters, and time from bite to enrolment (median 5 hours) were similar between groups. The median time to recovery from neurotoxic paralysis was 42.5 hours (IQR, 29.8-54.3) in the 10-vial group and 45.0 hours (IQR, 35.5-59.5) in the 20-vial group (median difference, -5.0 hours; 95% CI, -15.5 to 5.5; P = 0.24); Kaplan-Meier analysis showed no significant between-group difference (log-rank P = 0.38). Invasive mechanical ventilation was required in 34.6% of patients in the 10-vial group and 22.2% in the 20-vial group (risk ratio, 1.34; 95% CI, 0.77 to 2.31). Among ventilated patients, the median time to intubation and duration of mechanical ventilation were similar between groups. One death occurred in the 10-vial group.

Routine escalation of antivenom dosing may not be necessary in krait neurotoxicity with close respiratory monitoring and supportive care.

Among patients with neuroparalytic krait envenomation who presented without respiratory failure, a 10-vial antivenom regimen was associated with clinical outcomes comparable to those with a 20-vial regimen.