What specific inactive ingredients are commonly found in veterinary ivermectin formulations for horses?

1. What the official labels always show: the active and format

Every manufacturer page and DailyMed label in the results clearly identifies ivermectin as the active antiparasitic and specifies concentration or dose format—e.g., 1.87% oral paste syringes or a 10 mg/mL oral liquid—and packaging geared to treat large horses (syringes calibrated to ~1250 lb; dose = 200 µg/kg) ^{[1] [2] [5] [3]}. Those labels focus on indications, dosing, safety and environmental warnings rather than listing a standardized set of inactive ingredients across brands ^{[1] [2]}.

2. Inactive ingredients that appear in reporting and some labels

Reporting and some product notes name a short set of inert components commonly associated with horse pastes: corn oil (as a carrier), polysorbate 80 (an emulsifier/surfactant), apple flavor (palatability), and aerosil (colloidal silica, used to adjust texture); an early item in the search explicitly lists that combination as “non‑medicinal ingredients in most horse paste” ^[4]. Vendor and product summaries repeatedly describe paste consistency, flavoring and oil bases—supporting the idea that oil carriers plus flavoring and texture agents are typical—even if not all individual product labels in our set publish the full excipient list ^{[6] [7]}.

3. Variation by product: paste vs liquid and brand differences

Sources show there are both paste (disposable syringe) and liquid oral drench presentations; the liquid is described as a “clear, ready‑to‑use solution” (10 mg/mL) while pastes are “clean, white, homogeneous” preparations in syringes ^{[5] [3]}. That difference implies differing inactive ingredient needs—liquids rely more on solvents/carriers and preservatives, pastes on oils, thickeners and flavorants—so the exact inactive list will vary by brand and formulation ^{[5] [3]}.

4. Safety and the limits of the public labels

Manufacturers and regulators repeatedly warn that these products are for horses only and note environmental hazards from ivermectin residues; several pages highlight dosing and disposal, not ingredient transparency ^{[1] [2] [5]}. Independent sites and seller blogs raise the issue that inactive ingredients in veterinary products “haven’t been tested for human safety,” but those sources are advocacy/retail oriented and do not replace explicit ingredient tables from a given product label ^{[8] [4]}. If you need excipient specifics for clinical, allergy or regulatory reasons, the product’s full DailyMed label or manufacturer technical data sheet is the authoritative source—some DailyMed entries in the results are updated but still do not uniformly list every non‑medicinal ingredient ^{[1] [2]}.

5. Practical next steps and what reporting doesn’t say

If you require a definitive ingredient list for a particular brand or lot, obtain the product’s official label or technical data sheet from DailyMed, the manufacturer (e.g., Farnam, Boehringer Ingelheim, Durvet) or the vendor; several entries here show product pages and DailyMed records that include concentrations, dosing and some formulation descriptors but not always the full excipient roster ^{[1] [3] [6]}. Available sources do not present a single, authoritative, industry‑wide catalogue of inactive ingredients across all equine ivermectin products ^{[1] [2] [3]}.

Summary takeaway: published materials in this set show common inactive components reported for some equine ivermectin pastes—corn oil, polysorbate 80, apple flavor, and aerosil—while also demonstrating that specific excipient lists vary by formulation (paste vs liquid) and brand, and that many official pages focus more on dosing and safety than exhaustive inactive‑ingredient disclosure ^{[4] [5] [3]}.