There are 6 main categories of wormers and then some of these categories can be combined to make some dual wormers. How long the wormer will remain effective in the horse’s system for depends on the type of wormer it is.
Ivermectin; This group included Eqvalan, Eraquelle, Vectin, Noromectin, Bimectin and Animectin. This group of wormers are effective for 8-10 weeks. They treat worms such as lungworm, red worm, roundworm and bots. They don’t treat the larvae that have burrowed into the gut wall however (encysted).
Moxidectin; This group includes Equest. This wormer stays in the system for 13 weeks. They treat small redworm, bots and roundworm. This shouldn’t be given to horses that may have a large worm burden as once the worms in the gut have been killed off, more may emerge from inside the gut wall and this can cause colic.
Praziquantel; This group includes Equitape. This treats tapeworm and is a one-off treatment which doesn’t have lasting effects in the horse once it has killed the worms that are present.
Pyrantel; This group includes Strongid-P, Pyratape-P, Exodus and Embotape. This lasts in the horse’s system for 4-6 weeks. Treat nematode worms. Some of these wormers may be given at a double dose to treat tapeworm.
Fenbendazole; This group includes Panacur and Panacur Equine Guard 5 day course. This lasts in the horse’s system for 6-8 weeks. These also treat nematodes but some will not kill them if they are encysted in the gut wall. The 5 day course kills these encysted worms.
Mebendazole; This group includes telmin. This lasts in the horse’s system for 6-8 weeks. This doesn’t treat encysted worms.
When looking at the dual wormers, this include Equest Pramox which is a Moxidectin and Praziquantel and Equimax and Eqvalan Duo which is Ivermectin and Praziquantel. These wormers treat for tapeworm along with other types of worms such as bots.Love Laura