Evaluation of dimethyl sulphoxide effects on initial response to endotoxin in the horse.
Authors: Kelmer G, Doherty T J, Elliott S, Saxton A, Fry M M, Andrews F M
Journal: Equine veterinary journal
Summary
Endotoxaemia represents one of the most challenging conditions in equine practice, yet the evidence base for many therapeutics remains limited. Kelmer and colleagues investigated whether dimethyl sulphoxide (DMSO)—a drug commonly administered in equine medicine—could attenuate the physiological response to experimentally induced endotoxaemia in 18 horses randomised to receive intravenous lipopolysaccharide (LPS) with either saline, high-dose DMSO (1 g/kg) or low-dose DMSO (20 mg/kg). Although high-dose DMSO successfully reduced fever development following LPS administration, it failed to meaningfully ameliorate other cardinal signs of endotoxaemia, including the clinical inflammatory response, changes in white blood cell counts, tumour necrosis factor-alpha elevation, or alterations in blood lactate and glucose concentrations. These findings suggest that whilst DMSO may offer modest antipyretic benefits in endotoxaemic horses, clinicians should not expect this agent to substantially modify the broader systemic inflammatory cascade or multi-organ effects characteristic of gram-negative sepsis. The limited efficacy documented here warrants reconsideration of DMSO's role as a monotherapy in endotoxaemia and highlights the continued need for evidence-based evaluation of adjunctive treatments in this life-threatening condition.
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Practical Takeaways
- •While DMSO is commonly used clinically in horses, this study shows it provides minimal benefit in endotoxaemic cases, with only modest fever reduction at high doses
- •DMSO does not meaningfully improve other key parameters of endotoxaemia (inflammatory markers, metabolic derangements, white cell counts), so practitioners should not rely on it as a primary endotoxaemia treatment
- •Alternative or adjunctive therapies should be considered as primary interventions for managing equine endotoxaemia rather than DMSO monotherapy
Key Findings
- •High-dose DMSO (1 g/kg) ameliorated LPS-induced fever, the only significant clinical parameter affected
- •DMSO at either dose (20 mg/kg or 1 g/kg) did not significantly affect LPS-induced changes in white blood cell counts, plasma TNF-alpha, blood lactate, or glucose concentrations
- •All horses receiving LPS developed endotoxaemia as evidenced by clinical signs, haemoconcentration, and leucopenia
- •Overall, DMSO had minimal effects on clinical signs of induced endotoxaemia in horses despite fever amelioration