| Drench groups and actives | Worms | Examples* of brand names/comments |
| BZ or benzimidazole group (‘white’)B albendazole fenbendazole oxfendazole | barber’s pole worm, ‘scour worms’, adult liver fluke, nodule worm, aids control of intestinal tapeworm (Moniezia) | Valbazen (albendazole) WSD Fenbendazole (fenbendazole) Oxfen (oxfendazole) |
| LV or levamisole group (‘clear’)B levamisole | barber’s pole worm, ‘scour worms’, nodule worm | Nilverm, Levamisole Gold |
| ML or macrocyclic lactone groupB (sometimes called ‘mectins’) Ivermectin abamectin moxidectin | barber’s pole worm, ‘scour worms’, nodule worm | Ivomec, Noromectin (ivermectin) Absolute, Vetmec, Paramectin (abamectin) Cydectin, Moxitak (moxidectin) |
| AAD or amino-acetonitrile derivative groupB monepantel | barber’s pole worm, ‘scour worms’ | Zolvix |
| SI or spiroindole groupM derquantel | barber’s pole worm, ‘scour worms’, nodule worm | Derquantel is only found in a combination: Startect (abamectin + derquantel)B |
| OP or organophosphate groupM naphthalophos (NAP) (OPs have lower or variable efficacy against ‘scour worms’ in the upper GIT and immature barber’s pole worm) | barber’s pole worm, ‘scour worms’ | Rametin, (naphthalophos is commonly used in combinations) |
| TZ or benzimidazole group (flukicide)N triclabendazole | Liver fluke (all stages); not effective against round worms | Fasinex, Tremacide, Exifluke |
| SA or salicylanilides/phenols groupN closantel | Liver fluke (> 9 weeks and adult) and barber’s pole worm | Closicare, Sustain |
| IQ or isoquinolone groupN praziquantel | Intestinal tapeworm (Moniezia) | PraziquantelN is only available in combination with broad-spectrum drenches. First DrenchB, Genesis TapeB |
*ParaBoss does not endorse specific brands, these are presented here as examples only.
Breadth of activity across different worm species: BBroad-spectrum; MMid-spectrum; NNarrow-spectrum
Actives: An ‘active’ is the chemical in a drench responsible for killing worms. Some drenches have more than one active and are called ‘multi-active’ or ‘combination’ drenches.
Combination or multi-active treatments: Proprietary treatments containing more than one active. Formulated to be compatible as a mixture. Note: Do not mix your own drenches unless the labels state that you can.
Product formulation: All single actives are available as oral drenches. Moxidectin is also available in injectable products. Intra-ruminal/controlled release capsules are available with BZ and/or ML actives. Abamectin is also in a pour-on formulation for both lice and worm control.
Length of protection: Varies from short-acting (‘knock-down’ that kills susceptible worms within the animal) to mid-length (1–6 weeks) and long-acting (approx. 3 months), which not only kill susceptible worms already in the animals, but also infective larvae that the sheep eat during the protection period.
‘Scour worms’: Mainly black scour worm and (small) brown stomach worm, but also others.
Label: Check product labels for full details. Follow the label.
Other parasites: ‘Drenches’ shows effectiveness of groups against other parasites of minor importance.
