Brand: DECTOMAX ® Injectable Solution

Company: ZOETIS

FORMULATION: «injectable» to be administered to:

  • cattle: subcutaneoulsy (under the loose skin in front of or behind the shoulder) or intramuscular
  • swine: intramuscular
  • sheep: intramuscular

ACTIVE INGREDIENT(S): doramectin: 10 mg/mL (=1.0%)

CHEMICAL CLASS of the active ingredient(s): macrocyclic lactone


CATTLE, SHEEP, SWINE (Cattle everywhere; sheep & swine depending on the country)

PARASITES CONTROLLED* (spectrum of activity)

* Country-specific differences may apply: read the product label.





*Can be slightly different in some countries: read the product label!

  • Cattle: 200 mcg/kg bw, equivalent to 1 ml/50 kg (=110 lb) bw
  • Sheep:
    • 200 mcg/kg bw, equivalent to 1 ml/50 kg (=110 lb) bw for treatment against gastrointestinal worms, lungworms & nasal bots
    • 300 mcg/kg bw, equivalent to 1 ml/33 kg (= 75 lb) bw for treatment against sheep scab (Psoroptes ovis) and Nematodirus battus
  • Swine: 300 mcg/kg bw, equivalent to 1 ml/33 kg (=75 lb) bw


  • LD50 (acute oral) in rats: 500 to 2000 mg/kg (for the a.i., based on MSDS)
  • LD50 (acute dermal) in rats: 2000 mg/kg (for the a.i., source MSDS)
  • Estimated hazard class according to the WHO: not applicable for veterinary medicines

Suspected poisoning? Read the article on doramectin safety in this site.

Withholding periods (=withdrawal times) in days for meat & milk (country-specific differences may apply: read the product label)

  • Cattle: USA 35 (do not use in calves to be processed for veal); Canada 42; UK 70; Australia: 35 (do not use in calves to be processed for veal); New Zealand: 35.
  • Swine: USA 24; Canada 62; Australia 35; New Zealand 35.
  • Sheep: UK 70, New Zealand 35.

In most countries not approved for use on dairy animals producing milk for human consumption.

Non-lactating dairy cattle: in most countries treat at least 2 months prior to calving.

WARNING !!!: Never use on humans, dogs or cats


Risk of resistance? YES, in gastrointestinal roundworms in sheep (very high), goats (very high) and cattle (high) particularly in:

Resistance of gastrointestinal roundworms to macrocyclic lactones in sheep, goats and cattle has been reported in numerous countries. Most cases have been reported for ivermectin, but cross-resistance with doramectin has been demonstrated in several parasites and basically must be expected to occur. Based on the very abundant and frequent use of ivermectin and other macrocyclic lactones in livestock it must be assumed that resistance of gastrointestinal roundworms to this chemical class will continue spreading and strengthening in the future.

This means that if this product does not achieve the expected efficacy against the mentioned parasites, it may be due to resistance and not to incorrect use, which is usually the most frequent cause of product failure.

Alternative chemical classes/active ingredients to prevent resistance of gastrointestinal roundworms through product rotation:

These alternative products may not be available in all countries, or may not be available as injectables.

Resistance of cattle ticks Rhipicephalus (Boophilus) microplus to ivermectin has been reported in several Latin American countries. It is not yet a widespread problem, but nevertheless a warning. Based on the intensive use of macrocyclic lactones on cattle it is only a matter of time for resistance of cattle ticks to these compounds to develop elsewhere unless specific resistance preventative meaures (e.g. rotation, IPM, etc.) are taken.

Learn more about resistance and how it develops.


Are the active ingredients of this product ORIGINAL* or GENERICS**?


*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.

COUNTRIES where this brand/product is marketed: Worldwide, including the US, Canada, the EU, Australia, New Zealand, etc. In some countries marketed by other companies.
GENERIC BRANDS available? NOT in most English-speaking countries (YES in numerous Latin American countries). Although patent protection for doramectin expired years ago and there are manufacturers of generic doramectin, it happens that many Animal Health companies without an own macrocyclic lactone (ML) for livestock prefer generic ivermectin (or moxidectin and abamectin in some countries). A simple reason is that ivermectin was the first ML that lost patent protection and became available in the generics market. Another one is that the offer of generic ivermectin is much higher and thus prices lower than for doramectin or other MLs. Although doramectin may have some advantages over ivermectin in particular markets (e.g. sheep scab control), ivermectin or abamectin are often good enough for most indications.

For an overview on the most used antiparasitic injectable brands for livestock click here.

Click here to learn more about GENERIC vs. ORIGINAL drugs.


DECTOMAX 1% injectable is the first brand of doramectin launched by PFIZER AH (now ZOETIS) in the mid 1990s. After the tremendous success of ivermectin in the 1980s, all multinational Animal Health companies concentrated their efforts on discovering their own macrocyclic lactone comparable to ivermectin. PFIZER was one of the few companies that made it and introduced even two own macrocyclic lactones: doramectin for livestock and selamectin for dogs and cats.

Doramectin is generally considered as more potent than ivermectin against gastrointestinal nematodes of livestock, particularly in sheep and goats, and against a few other livestock pests (e.g. sheep scab, cattle ticks, etc.). It is also less toxic than ivermectin, which allows higher safety margins.

There are other formulations for topical (pour-on) administration, mainly for cattle and sheep.

Whereas DECTOMAX 1% injectable is approved for use on cattle worldwide, approval for use on sheep and/or swine depends on the country.

In Australia the DECTOMAX 1% injectable has a claim for up to 28 days control of cattle ticks Rhipicephalus (Boophilus) microplus. Doramectin efficacy against these ticks is slightly better that the one of ivermectin, but still usually insufficient for most producers.

The different withholding periods in various countries illustrate the fact that unfortunately, national regulatory authorities often draw different conclusions from exactly the same scientific evidence. This has been always so and there are no indications that things will improve in the near future.

Being an excellent antiparasitic comparable to ivermectindoramectin does not control all parasites of livestock. Unfortunately advertising and even the label of some generic formulations in less developed countries often include unsubstantiated claims. To help preventing confusion and misuse it is useful to know that whatever doramectin 1% injectable used at the recommended dose DOES NOT CONTROL:

Click here for general information on good practices for the prevention and control of gastrointestinal worms in livestock.


This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics. 

Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.

In case of doubt contact the manufacturer or a veterinary professional.