Randomized Controlled Trial of Intravenous Antivenom Versus Placebo for Latrodectism: The Second Redback Antivenom Evaluation (RAVE-II) Study

Abstract

1 Randomized controlled trial of intravenous antivenom versus placebofor latrodectism: the second redback antivenom evaluation (RAVE-II) study. AbstractObjective: Latrodectism is the most important spider envenomation syndrome worldwide.There remains considerable controversy over antivenom treatment. We aimed to investigate whether antivenom resulted in resolution of pain and systemic effects in patients with latrodectism given standardized analgesia.Methods: In a multicentre randomized placebo-controlled trial of redback spider antivenom for latrodectism, 224 patients (>7yr) with a redback spider-bite and severe pain with or without systemic effects were randomized to receive normal saline (placebo) or antivenom, after receiving standardized analgesia. The primary outcome was a clinically significant reduction in pain 2 hours after trial medication compared to baseline. A second primary outcome for the subgroup with systemic features of envenomation was resolution of systemic features at 2 hours. Secondary outcomes were improved pain at 4 and 24 hours, resolution of systemic features at 4 hours, administration of opioid analgesics or unblinded antivenom after 2 hours and adverse reactions.Results: Two hours after treatment, 26/112 patients (23%) from the placebo arm had a clinically significant improvement in pain versus 38/112 (34%) from the antivenom arm (difference in favor of antivenom 10.7%;95%CI:−1.1% to +22.6%;p=0.10). Systemic 2 effects resolved after two hours in 9/41 patients (22%) in the placebo arm and 9/35 (26%) in the antivenom arm (difference 3.8%;95%CI:−15% to +23%;p=0.79). There was no significant difference in any secondary outcome between antivenom and placebo. Acute systemic hypersensitivity reactions occurred in 4/112 (3.6%) patients given antivenom.Conclusions: The addition of antivenom to standardized analgesia in patients with latrodectism, did not significantly improve pain or systemic effects.

Hot water immersionvicepacks for treating the pain ofChironex fleckeristings: a randomised controlled trial

“…The VAS is one of the most commonly used, including in earlier studies of blue bottle stings 1 and red‐back spider bites 10 . More recent studies have employed a verbal numerical rating score because it is easier to administer (paper is not required) 11 and it is used in clinical practice; management of C. fleckeri stings should now include regular assessment of the pain with the verbal numerical score. Correcting for the baseline pain score is controversial, but it enables comparison of patients with differing severity of subjective pain, and this approach has been applied in three previous studies of painful envenoming syndromes 1 , 10 , 11 .…”

Venom and Antivenom of the Redback Spider (<i>Latrodectus hasseltii</i>) in Japan. Part II. Experimental Production of Equine Antivenom against the Redback Spider

“…From an efficacy perspective, there are reports that the overseas commercial product was effective in patients with bites from not only redback spider but also other spider species (28)(29)(30)(31)(32)(33)(34)(35). However, there are also conflicting reports that the use of antivenom is not significantly effective in treating patients with bites when an analgesic is used in combination or when an analgesic is the primary treatment choice (36,37). Therefore, future clinical applications should take these aspects into account.…”

Clinical Serum Therapy: Benefits, Cautions, and Potential Applications

“…52 In 2014, Isbister et al conducted a RCT to evaluate the effect of redback antivenom, and concluded that the addition of antivenom to standardized analgesia in patients with latrodectism did not significantly improve pain or systemic effects. 53 However, that study has raised some concerns. In Australian emergency departments, some patients with redback spider bites, including children, pregnant women, and the elderly, have increased risks of developing severe or systemic symptoms and are more likely to receive antivenom.…”