Horse Dewormers & Parasite Control

Horse Dewormer Paste for Internal Parasite Control — Worms, Bots, Lungworms & More

• 1.87% Ivermectin Formula: DuraMectin and Bimectin both contain 1.87% ivermectin in a single-dose syringe, treating horses up to 1,250 lb body weight.
• Fenbendazole Option: Panacur Equine Paste 10% provides an alternative active ingredient — effective against stomach worms, lungworms, and intestinal parasites where ivermectin resistance is a concern.
• Safe for All Life Stages: Ivermectin-based pastes are approved for use in horses of all ages, including mares at any stage of pregnancy.
• Easy Oral Administration: Weight-marked dosing syringe makes accurate administration straightforward — no mixing, no measuring cups.
• Palatability Aids Compliance: Panacur is apple-flavored to reduce resistance at dosing time, particularly useful for horses that resist oral paste treatment.

How to Choose the Right Horse Dewormer

Active Ingredient

The two main active ingredients available here are ivermectin (1.87%) and fenbendazole (10%). Ivermectin covers a wide range of parasites including bots. Fenbendazole, found in Panacur, is commonly used in rotation protocols or when targeting parasites such as lungworms and certain intestinal worms that may show reduced sensitivity to ivermectin.

Deworming Rotation

Many equine health professionals recommend rotating between active ingredients across treatment cycles to reduce the risk of parasite resistance. Alternating between an ivermectin-based product and a fenbendazole-based product throughout the year is a widely practiced approach in routine equine parasite management programs.

Horse Age and Status

All three products in this collection are labeled for use in horses of all ages. Both ivermectin pastes are confirmed safe for pregnant mares. Always verify current product labeling for stallions being used for breeding and consult your veterinarian for foals under four months of age.

Common Mistakes When Deworming Horses

Under-dosing is the most common error — always dose by actual body weight, not estimated size. Using the same active ingredient every cycle also accelerates resistance. A third mistake is skipping treatment for new horses before they integrate with the herd, which risks spreading resistant parasite populations across the whole group.

Ivermectin vs Fenbendazole Horse Dewormers — Which Should You Use?

Ivermectin Paste (DuraMectin, Bimectin — 1.87%)

Ivermectin is one of the most widely used anthelmintics in equine care, effective against a broad range of internal parasites including large and small strongyles, ascarids, pinworms, and bot fly larvae. Both DuraMectin and Bimectin deliver the same 1.87% concentration in a weight-graduated oral syringe. Best for: routine deworming cycles, bot fly treatment, and horses requiring a proven broad-spectrum option.

Fenbendazole Paste (Panacur 10%)

Panacur Equine Paste uses 10% fenbendazole to target lungworms, stomach worms, and intestinal parasites. Its apple flavor improves acceptance in horses that resist syringe dosing. Fenbendazole is a valuable component of rotation programs and is commonly used as part of a larvicidal dose protocol under veterinary guidance. Best for: rotation protocols, lungworm treatment, and palatability-sensitive horses.

Deworming frequency depends on your horse's parasite burden and your veterinarian's guidance. Many owners follow a strategic deworming program based on fecal egg counts, treating two to four times per year. Rotating between ivermectin-based and fenbendazole-based dewormers across cycles is a common practice to reduce the risk of parasite resistance developing over time.

Yes — both DuraMectin and Bimectin (1.87% ivermectin paste) are labeled for use in mares at any stage of pregnancy. Always follow current product labeling and consult your veterinarian if you have specific concerns about your mare's health status or any concurrent medications being administered.

Ivermectin (DuraMectin, Bimectin) and fenbendazole (Panacur) work through different mechanisms and target overlapping but not identical parasite spectrums. Ivermectin is effective against bots and a wide range of worms. Fenbendazole targets lungworms, stomach worms, and intestinal parasites and is commonly used in rotation or larvicidal protocols. Using both across the year supports a more comprehensive parasite management program.

Administer paste when the horse's mouth is empty — check there is no hay or feed present. Insert the syringe from the corner of the mouth and deposit the paste as far back on the tongue as possible, then hold the horse's head slightly elevated for a few seconds. Panacur's apple flavor can improve acceptance for horses that are particularly resistant to oral dosing.

Dosing is based on body weight. The DuraMectin and Bimectin syringes feature weight-graduated markings (250–1,250 lb) printed directly on the barrel. Set the dial to your horse's actual body weight — use a weight tape if you do not have a scale — and administer the full set dose in a single oral application. Never under-dose, as this is the leading cause of treatment failure.