What should be monitored in patients on atropine sulfate?

• A. Blood pressure
• B. Heart rate
• C. Manure production
• D. Appetite

Answer: (C)

Atropine sulfate is an anticholinergic that blocks parasympathetic input to the GI tract, reducing motility and secretions. In horses, this can slow gut peristalsis and lead to ileus, so tracking fecal output is a sensitive and practical way to assess GI function during its use. A decline in manure production signals decreased intestinal activity and a risk of colic, which is the key concern with atropine administration in this species. While heart rate can rise with anticholinergic effects and other factors can influence blood pressure or appetite, these are less specific indicators of atropine’s GI impact. Monitoring manure production directly targets the most relevant adverse effect.