Incorporating Praziquantel into Your Deworming Program

Written by: Dr. Jay Altman

New deworming products containing praziquantel have recently become available.  Praziquantel is effective against tapeworms.  Contrary to popular opinion, tapeworms are not associated with weight loss in horses.  They are however associated with chronic colic.  Due to the great length of the equine intestinal tract, tapeworm segments are often broken down before exiting in the feces and cannot be found.  Although not impossible, it is difficult to diagnose a tapeworm infestation and therefore it is best take preventative steps.

Our previous deworming program recommended using a double dose of pyrantel for tapeworms in adult horses.  Praziquantel is believed to be more effective against tapeworms than pyrantel and if incorporated in our program, using a double dose of pyrantel is unnecessary.  Praziquantel is available combined with ivermectin or moxidectin.  Cautions applied to the use of moxidectin (see Note 1 below) apply equally to the moxidectin/praziquantel combination product, and using ivermectin/praziquantel in these cases would be advised.

The following is an outline of a concise and effective paste-deworming program recommended by Equine Medical Service, which incorporates praziquantel.  For more information regarding deworming concepts, please refer to the article written in the Fall 2001 Newsletter.

Every horse beginning at about 6 weeks of age needs to be dewormed on a regular basis.  I recommend that during the first six months of life the foal be dewormed approximately every 30 days.  Once the foal is one year of age the program should be changed to the following adult horse program.

Foals

6 weeks	Fenbendazole (DD)
9 weeks	Ivermectin
12 weeks	Ivermectin
16 weeks	Fenbendazole (DD-5D)
20 weeks	Ivermectin
24 weeks	Ivermectin
32 weeks	Pyrantel Pamoate (DD)
40 weeks	Ivermectin
48 weeks	Ivermectin/ Praziquantel

Adults

January	Moxidectin or Ivermectin with praziquantel
March	Oxibendazole
May	Moxidectin or Ivermectin
July	Fenbendazole
September	Moxidectin or Ivermectin **
November	Pyrantel Pamoate

(DD) = Double Dose; use double the recommended quantity (based upon weight)
(DD-5D)=Double dose for 5 consecutive days, time this procedure so that it is in the early fall (September or October).
** Yearlings should be given Panacur ( fenbendazole) (DD-5D) in the early fall just as done for the foals.

Trade Names:
Ivermectin= Eqvalan, Equimectrin, Ivercure
Ivermectin with praziquantel= Equimax, Zimecterin Gold
Moxidectin= Quest
Moxidectin with praziquantel= Quest Plus
Fenbendazole= Panacur, Safe Guard
Pyrantel Pamoate= Strongid
Oxibendazole= Anthelcide EQ

Notes:

1. I do not recommend the use of moxidectin (Quest), in horses less than 2 years of age, thin or under weight horses, debilitated horses, or horses that are geriatric and suffering from Cushings Disease.
2. Once your youngster reaches one year of age he or she can be switched to the adult program utilizing ivermectin vs. moxidectin.
3. For specific recommendations regarding geriatric, Cushings, and ill horses please consult with your regular veterinarian.
4. The adult plan calls for at least one (I prefer two) moxidectin dewormings per year, if only once I prefer to administer this one in September.
5. Read dosage parameters on the dewormer labels be careful not to over dose the dewormer although a 20 –25% overdose is not normally a problem for the horse.
6. Consult with one of the Equine Medical Service veterinarians before deworming any horse that has not had regular dewormings, or that you do not know the prior deworming history.

Additionally I recommend that an annual fecal sample be collected and analyzed to test the efficacy of both the scheduling and products you have selected.  I also urge good management practices, which include pasture management and manure disposal to keep your horse healthy and prevent the building of a worm population in your horse.