What Doramectin Is
Doramectin is a semi-synthetic macrocyclic lactone endectocide derived from ivermectin and belonging to the avermectin family. Its CAS registry number is 117704-25-3. It is active against a broad spectrum of internal parasites such as gastrointestinal nematodes and lungworms, and external parasites such as mites, lice and grubs. Doramectin is formulated as an injectable solution and as a pour-on product for use in cattle, pigs, sheep and other species according to local approval.
Because the molecule combines endoparasiticidal and ectoparasiticidal activity in a single treatment, it belongs to the group known as endectocides. Material is supplied as a sterile solution or as a topical formulation, and quality control focuses on assay, related substances and sterility of the injectable grade.
How Doramectin Works
Doramectin acts on the nervous system of parasites by binding to glutamate-gated chloride channels in the nerve and muscle cells of nematodes and arthropods. This binding increases the flow of chloride ions into the cells, causing hyperpolarisation, paralysis and death of the parasite. At higher concentrations it can also potentiate the inhibitory neurotransmitter GABA. Mammals do not possess these parasite-type glutamate-gated chloride channels, which is the main reason for the wide safety margin at therapeutic doses.
Which Animals and Parasites Can Be Treated
| Species | Main targets | Typical form |
|---|---|---|
| Cattle | Gastrointestinal roundworms, lungworms, cattle grubs, mange mites, lice | Injection or pour-on |
| Pigs | Sarcoptic mange caused by Sarcoptes scabiei, gastrointestinal nematodes | Injection |
| Sheep and other species | Approved indications vary by country | Injection |
Because doramectin is a veterinary medicine, it must be used strictly according to the label and to local veterinary regulations, and only for the species and conditions listed on that label.
Injectable and Pour-On Formulations
The injectable formulation provides a convenient single-dose treatment with persistent activity against many parasites. The pour-on formulation is applied along the backline of the animal and is especially convenient for treating external parasites in cattle. Both forms reduce handling stress compared with repeated dosing. The choice between them depends on the parasite species, the production system and the label approval in each market.
Single-dose handling lowers labour input and animal stress.
Persistent activity extends the interval between treatments.
Pour-on application avoids injection-site reactions in cattle.
Product selection must follow the approved indication list.
Safety, Withdrawal Periods and Resistance Management
Doramectin must not be used in animals producing milk for human consumption during the withdrawal period, and meat withdrawal times must be respected before slaughter. Accidental self-injection is dangerous because avermectins are toxic to humans at high doses, so syringes must be handled with care. Certain dog breeds carrying the MDR1 gene defect are highly sensitive to avermectins, so products must never be given to non-target species. To slow the development of resistance, use doramectin as part of a planned parasite control programme and avoid underdosing. Rotating active ingredients and monitoring faecal egg counts support sustainable use on farm.
Frequently Asked Questions
Q: What is doramectin used for?
Doramectin controls internal nematodes and external parasites such as mites, lice and grubs in cattle, pigs, sheep and other species where approved.
Q: How does doramectin kill parasites?
It binds glutamate-gated chloride channels in parasite nerve and muscle cells, causing paralysis and death, while having a wide safety margin in mammals.
Q: Can doramectin be used in pigs?
Yes. Doramectin is used in pigs for sarcoptic mange and gastrointestinal nematodes where it is locally approved.
Q: What is the CAS number of doramectin?
The CAS registry number of doramectin is 117704-25-3.
Q: What withdrawal period applies to doramectin?
Withdrawal periods for meat and milk are set on the approved label and differ by country and formulation, so the label must always be followed.
Q: Why is doramectin called an endectocide?
It is called an endectocide because a single active substance controls both internal nematodes and external arthropod parasites.