Plasma atropine concentrations associated with decreased intestinal motility in horses.
Authors: Ekstrand Carl, Michanek Peter, Gehring Ronette, Sundell Anna, Källse Annika, Hedeland Mikael, Ström Lena
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Atropine and Equine Intestinal Motility Atropine's antimuscarinic effects make it invaluable for treating equine uveitis, yet topical ophthalmic application frequently precipitates colic-like signs through systemic absorption—a paradox that has limited our ability to optimise dosing schedules without quantitative data on gastrointestinal effects. Ekstrand and colleagues established plasma atropine concentrations at which intestinal motility becomes measurably suppressed in horses, filling a critical gap in the pharmacodynamic literature by correlating drug levels with objective reductions in gut function. Their work demonstrates threshold plasma concentrations associated with clinically significant motility inhibition, providing the quantitative framework previously absent from equine pharmacology. These findings enable evidence-based refinement of atropine dosing protocols—particularly regarding the interval between applications—to balance uveitic treatment efficacy against colic risk. For practitioners, the study supports tailoring atropine frequency according to individual patient absorption patterns and clinical response, whilst maintaining vigilance for gastrointestinal complications when plasma concentrations exceed established thresholds.
Read the full abstract on PubMed
Practical Takeaways
- •When treating equine uveitis with topical atropine, use the minimum effective dosing frequency (every 6 hours preferred) to reduce risk of colic-like signs and intestinal dysmotility
- •Monitor treated horses closely for signs of abdominal discomfort and reduced gut sounds, as systemic absorption of topical atropine can cause clinically significant gastrointestinal effects
- •Use plasma atropine concentration thresholds identified in this study to guide dosing decisions and identify horses at higher risk for motility complications
Key Findings
- •Topical atropine administration for equine uveitis is associated with decreased intestinal motility and abdominal pain
- •Frequent atropine dosing carries higher risk of gastrointestinal side effects than dosing every 6 hours
- •Study provides first quantitative pharmacodynamic data for atropine-induced inhibition of equine gut motility