There are 5 different drench groups/classes you should be aware of when treating gastrointestinal worms. Generally speaking, if you have drench resistance to one product within a group, there will be drench resistance to all products in that group.
- BZ = benzimidazoles = “white” drenches
- LEV = levamisole = “clear” drenches
- ML = macrocyclic lactones = “mectin” drenches
- MON = monepantel = “orange” drenches
- CLOS = closantel = barber’s pole worm specific drench
When you are buying drench, READ THE FINE PRINT to work out which drench class you are buying from! Ask your veterinarian to assist you. Have a look at the Worm Boss site for more information about different drenches.