Unique Mode of Action


Panacur Powerpac


Unique mode of action is what makes PANACUR® (fenbendazole) so effective against the most dangerous parasites of the horse..

  • Proven Safe – Safe for foals, pregnant mares and older horses1
  • Works on a wide variety of parasites – Labeled for the control of large and small strongyles (including migrating larvae), pinworms and ascarids (roundworms)1
  • Effective on encysted small strongyles – A larvicidal dose is the only FDA-approved treatment for all stages of encysted small strongyles1
  • Reliable protection for foals – Widely recognized as the product of choice for treating ascarids in young horses2,3,4
  • Combat resistance – May be effective even in the face of prior fenbendazole resistance when used as part of a strategically designed anthelmintic program1
  • Unique Mode of Action – The antiparasitic action of PANACUR (fenbendazole) POWERPAC is due to the inhibition of energy metabolism in the parasite5


PANACUR (fenbendazole) Paste 10% is indicated for the control of large strongyles (Strongylus edentatus, S. equinus, S. vulgaris), encysted early third stage (hypobiotic), late third stage and fourth stage cyathostome larvae, small strongyles, pinworms (Oxyuris equi), ascarids (Parascaris equorum) and arteritis caused by hypobiotic larvae of Strongylus vulgaris in horses.



PANACUR (fenbendazole) Paste 10% is administered orally at a rate of 2.3 mg/lb (5 mg/kg) for the control of large strongyles, small strongyles, and pinworms. One 57 gram syringe will deworm a 2,500 lb horse. For foals and weanlings (less than 18 months of age) where ascarids are a common problem, the recommended dose is 4.6 mg/lb (10 mg/kg); one 57 gram syringe will deworm one 1,250 lb horse.

For control of encysted early third stage (hypobiotic), late third stage and fourth stage cyathostome larvae, and fourth stage larvae of Strongylus vulgaris, the recommended dose is 4.6 mg/lb (10 mg/kg) for 5 consecutive days; administer one 57 gram syringe for each 1,250 lbs of body weight per day.

Consult your veterinarian for assistance in the diagnosis, treatment and control of parasitism.

Important Safety Information

Do not use in horses intended for human consumption. When using PANACUR (fenbendazole) Paste 10% concomitantly with trichlorfon, refer to the manufacturer’s labels for use and cautions for trichlorfon.



Keep your clinic up-to-date on the Merck Animal Health line of equine products.

Using PANACUR POWERPAC to Treat Ivermectin-Resistant Ascarids in Foals

Panacur® POWERPAC is FDA approved to treat all stages of the encysted small strongyle.


The Science of Effective

Different for a reason.

Man handing woman a bucket with horse in background

Equine Product Reference Guide

A guide to the entire equine product line from Merck Animal Health.


The Science of Unique Deworming

Maximize your horse’s health from the inside out.


No items to show.



1. PANACUR® (fenbendazole) POWERPAC equine dewormer product label. 2. Reinemeyer CR, Prado JC, Vaala WE. Larvicidal efficacy of fenbendazole against a macrocyclic lactone-resistant isolate of Parascaris equorum in foals. Proceedings of the 55th Annual Meeting of the American Association of Veterinary Parasitologists, 2010, Atlanta, GA, p49. 3. AAEP Parasite Control Guidelines. Revised February 2016. 4. Cribb, NC, Cote, NM, Bouré, LP, Peregrine, AS. Acute small intestinal obstruction associated with Parascaris equorum infection in young horses: 25 cases (1985-2004). N Z Vet J. 2006 Dec;54(6):338-43. 5. Lacey E. Mode of Action of Benzimidazoles. Parasitology Today, vol. 6, no. 4, 1990.