Critical tests of activity of dl-tetramisole against the internal parasites of horses.

The study tested different doses of tetramisole, a medication, to see how effective it was in removing certain parasites from horses. The largest doses were the most successful, but also caused side effects in one horse.

Research Methodology

• The researchers tested five different doses of a medication called tetramisole on horses. The doses were 2.2, 5, and 10 mg/kg given subcutaneously (under the skin), and 20 and 30 mg/kg given orally.
• They conducted nine ‘critical tests’, which likely involved measuring the presence of different types of parasites before and after the medication was given.

Findings

• A parasite called Parascaris equorum was removed in 83 to 100% of cases with all of the doses.
• 98% of Strongylus vulgaris, another type of parasite, were removed by the two largest doses.
• The largest doses only removed 38-54% of S. edentatus, yet another type of parasite.
• The dose of 30 mg/kg removed 74% of small strongyles, which are another group of parasites.
• Results against mature Oxyuris equi, which is a type of worm, were variable.
• Only 13% of immature oxyurids were removed at 30 mg/kg. Oxyurids are a type of roundworm.
• The medication had no effect on Gastrophilus intestinalis and G. nasalis, which are types of flies that can cause stomach upsets in horses.

Side effects

• Toxicosis, which is poisoning, occurred only in the horse given the largest dose. It was characterized by hyperexcitability, sweating, and heavy tearing. This lasted about 6 hours.

Conclusions

• Tetramisole was effective in removing some parasites from horses at different dosages.
• However, the largest dose caused temporary adverse effects in one horse, which suggests there might be a risk of toxicity at higher doses.