Eqvalen is Merial’s liquid ivermectin dewormer. It is a prescription item but may be dispensed to owners for drench deworming. One 100 mL bottle will treat 10 average-size horses.
The FDA and Merial have issued statements concerning changes to the label of Eqvalen. The instructions now are that opened bottles or diluted product should be discarded after four hours. This change was made because of reports of a precipitate forming in some open bottles or bottles with evidence of leakage. This is easily missed since the bottles are white. It is currently unknown whether the precipitate is harmful or interferes with the effectiveness of the product but any physical change like this is generally considered a reason not to use a drug.
Merial is also recommending unused drug be mixed with kitty litter, sawdust or another absorbent material then placed in a sealed container or plastic bag before disposal. This limits the risk of unwanted environmental effects on aquatic systems or beneficial insects.