Brand: PANACUR ® PASTE 10%

Company: MERCK ANIMAL HEALTH = MSD ANIMAL HEALTH

FORMULATION: «oral paste» in pre-charged syringes

ACTIVE INGREDIENT(S): fenbendazole: 10% (= 100 g/kg)

CHEMICAL CLASS of the active ingredient(s): benzimidazole

INDICATIONS

HORSES

PARASITES CONTROLLED* (spectrum of activity)

* Country-specific differences may apply: read the product label.

• Control of large strongyles (Strongylus edentatus, Strongylus equinus, Strongylus vulgaris), encysted early third stage (hyobiotic), late third stage and fourth stage cyathostome larvae, small strongyles, pinworms (Oxyuris equis) ascarids (Parascaris equorum), and arteritis caused by fourth stage larvae of Strongylus vulgaris in horses.

RECOMMENDED DOSE*

*Can be slightly different in some countries: read the product label!

• 2.3 mg/lb (5 mg/kg) for the control of large strongyles, small strongyles, and pinworms.
• One syringe will deworm a 1,100 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 syringe will deworm a 550 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) daily for 5 consecutive days; administer one syringe for each 550 lbs body weight per day.

SAFETY

• LD50 (acute oral) in rats: >5000 mg/kg (estimate calculated according to the WHO based on the LD50)
• Estimated hazard class according to the WHO: not applicable for veterinary medicines
  

Suspected poisoning? Read the articles on fenbendazole safety in this site.

Withholding periods (=withdrawal times) for meat & milk (country-specific differences may apply: read the product label)

• MEAT & OFFAL: US: Do not use in horses intended for human consumption
• MILK: Do not use in mares producing milk for human consumption.

WARNING !!!: Never use on humans, dogs or cats

You may be interested in the following articles in this site dealing with the general safety of veterinary products:

• Safety for humans
• Safety for domestic animals
• Safety for the environment
• Hazard classifications of pesticides

RESISTANCE PREVENTION

Risk of resistance? YES

• Small strongyles (cyathostomes). Resistance of small strongyles to benzimidazoles is widespread and frequent e.g. in the USA, UK and Europe, Argentina, Chile, Uruguay, etc. 
• Parascaris equorum: Cases of tolerance to benzimidazoles have been also reported (e.g. in the USA). 

This means that if this product does not achieve the expected efficacy against the mentioned parasites, it may be due to resistance and not to incorrect use, which is usually the most frequent cause of product failure.

Alternative chemical classes/active ingredients to prevent resistance of gastrointestinal roundworms through product rotation:

• Imidazothiazoles, mainly levamisole. Not approved for use in horses in many countries.
• Macrocyclic lactones: mainly ivermectin, moxidectin. But tolerance or resistance to these compounds have also been reported in Europe (e.g. in the UK, Germany, Italy), the USA, and Brazil.
  
• Tetrahydropyrimidines, mainly pyrantel (limited spectrum of activity), but resistance cases have also been reported (e.g. Australia, USA, Brazil, Japan).

These alternative products may not be available in all countries, or may not be available as oral pastes or gels.

Learn more about resistance and how it develops.

MARKETING

Are the active ingredients of this product ORIGINAL* or GENERICS**?

• GENERICS
  

*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.

COUNTRIES where this product is marketed (maybe under another TM): US, Canada and many other countries, but maybe a different formulation.
GENERIC BRANDS available? YES, worldwide by the dozens

Click here to learn more about GENERIC vs. ORIGINAL drugs.

COMMENTS

This product is a classic oral paste dewormer for horses from MERCK ANIMAL HEALTH with original fenbendazole. It is basically the same as SAFE-GUARD EQUINE DEWORMER (25 G), just with a different trade name.

Fenbendazole is a veteran benzimidazole introduced in the 1970s (by HOECHST → INTERVET → MSD ANIMAL HEALTH) that is abundantly used in livestock and horses, moderately in pets. It is a broad-spectrum anthelmintic effective against roundworms in the gut and the lungs, but not against those in the skin. It is also ineffective against gastric bots (Gasterophilus spp) or whatever external parasites. At the recommended dose it is also ineffective against horse tapeworms (Anoplocephala spp).

For an overview and a list of the most used oral paste & gel brands click here.

DISCLAIMER

This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics. 

Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.

In case of doubt contact the manufacturer or a veterinary professional.