Zermex 20 mg/ml LA Solution for Injection for Sheep

Unnecessary use of antiparasitics or use deviating from the instructions given in the
SPC may increase the resistance selection pressure and lead to reduced efficacy. The
decision to use the product should be based on confirmation of the parasitic species
and burden, or of the risk of infestation based on its epidemiological features, for each
individual herd.
Care should be taken to avoid the following practices because they increase the risk of
development of resistance and could ultimately result in ineffective therapy:
- Too frequent and repeated use of anthelmintics from the same class, over an
extended period of time
- Underdosing, which may be due to underestimation of bodyweight,
misadministration of the product, or lack of calibration of the dosing device (if
any).

Amended pages: October 2025
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Suspected clinical cases of resistance to anthelmintics should be further investigated
using appropriate tests (e.g. Faecal Egg Count Reduction Test). Where the results of
the test(s) strongly suggest resistance to a particular anthelmintic, an anthelmintic
belonging to another pharmacological class and having a different mode of action
should be used.
Resistance to macrocyclic lactones has been reported in Teladorsagia in sheep in a
number of countries. In 2008, throughout Europe, moxidectin resistance is very rare; it
has been reported in a single case involving a levamisole-, benzimidazole and
ivermectin-resistant strain of Teladorsagia circumcincta
moxidectin should be based on local (regional, farm) epidemiological information about
susceptibility of nematodes, local history of treatments and recommendations on how
to use the product under sustainable conditions to limit further selection for resistance
to anthelmintics. These precautions are especially important when moxidectin is being
used to control resistant strains.
Psoroptes ovis is an extremely contagious external parasite of sheep and cattle. To
ensure complete control, great care must be taken to avoid re-infestation, as mites
may be viable for up to 15 days off the animal. It is important that all animals which
have been in contact with infected ones are treated with an appropriate product.
Contact between treated, infected and untreated herds must be avoided until at least
seven days after treatment.
Resistance to moxidectin has been reported in Psoroptes ovis scab mites in sheep
and in cattle. Cases of side-resistance with other macrocyclic lactones (ivermectin and
doramectin) have been reported as well. The use of this product should take into
account local information about susceptibility of the target parasites, where available.

Special precautions for use in animals
This product has been formulated specifically for subcutaneous injection in the base of
the ear of sheep and must not be given by any other route of administration or to any
other species. In order to prevent abscesses a strict aseptic technique is
recommended.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals
Avoid direct contact with skin and eyes.
Wash hands after use.
Do not smoke, drink or eat while handling the product.
Take care to avoid self-injection. If this occurs, it is unlikely that any product related
symptoms will be observed. In case of accidental self injection, seek medical advice
immediately and show the package leaflet or the label to the physician. Advice to
Medical Practitioners in case of accidental self injection: Treat symptomatically.
Other precautions regarding impact on the environment
Moxidectin fulfils the criteria for a (very) persistent, bioaccumulative and toxic (PBT)
substance; therefore, exposure of the environment to moxidectin must be limited to the
extent possible. Treatments should be administered only when necessary and should

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be based on faecal egg counts or evaluation of the risk of infestation at the animal
and/or herd level.

Like other macrocyclic lactones, moxidectin has the potential to adversely affect non-
target organisms:
•
temporarily reduce the abundance of dung feeding organisms. Following
treatment of sheep with the product, levels of moxidectin that are potentially toxic
to dung fly species may be excreted over a period of more than 4 weeks and may
decrease dung fly abundance during that period. It has been established in
laboratory tests that moxidectin may temporarily affect dung beetle reproduction;
however, studies with incurred residues indicate no long-term effects.
Nevertheless, in case of repeated treatments with moxidectin (as with products of
the same anthelmintic class) it is advisable not to treat animals every time on the
same pasture to allow dung fauna populations to recover.
•
should be used only according to the label instructions. Based on the excretion
profile of moxidectin when administered as the injectable formulation to sheep,
treated animals should not have access to watercourses during the first 11 days
after treatment.