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Drench groups and actives

WormBoss worm control program

NSW non-seasonal rainfall


Drench groups and actives

Drench groups and actives Worms Examples* of brand names/comments

BZ or benzimidazole group (‘white’)B


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


barber’s pole worm, ‘scour worms’, nodule worm

Nilverm, Levamisole Gold

ML or macrocyclic lactone groupB (sometimes called ‘mectins’)


barber’s pole worm, ‘scour worms’, nodule worm

Ivomec, Noromectin (ivermectin)
Absolute, Vetmec, Paramectin (abamectin)
Cydectin, Moxitak (moxidectin)


AD or amino-acetonitrile derivative groupB


barber’s pole worm, ‘scour worms’ Zolvix

SI or spiroindole groupM


barber’s pole worm, ‘scour worms’,  nodule worm

Derquantel is only found in a combination: Startect (abamectin + derquantel)

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’

Combat, Rametin, (naphthalophos is commonly used in combinations)

TZ or benzimidazole group (flukicide)N


Liver fluke (all stages); not effective against round worms Fasinex, Tremacide, Exifluke

SA or salicylanilides/phenols groupN


Liver fluke (> 9 weeks and adult) and barber’s pole worm

Closicare, Sustain

IQ or isoquinolone groupN


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 (1–4 weeks) and long-acting (approx. 3 months), which not only kill susceptible worms already in the animals, but also susceptible 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.