Milbemycin oxime
Encyclopedia
Milbemycin oxime is a veterinary drug from the group of milbemycin
s, used as a broad spectrum antiparasitic. It is active against worms (anthelmintic
), insects (insecticide
) and mites (miticide
).
s, milbemycins are products of fermentation
by Streptomyces
species. They have a similar mechanism of action, but a longer half-life than the avermectins. Milbemycin oxime is produced by Streptomyces hygroscopicus aureolacrimosus. It opens glutamate sensitive chloride channel
s in neuron
s and myocyte
s of invertebrate
s, leading to hyperpolarisation
of these cells and blocking of signal transfer.
s than ivermectin. Its miticide spectrum includes Sarcoptes
and Demodex. The USA FDA approval for milbemycin oxime as formulated alone does not indicate insecticidal activity.
The substance is often combined with other parasiticides to achieve a broader spectrum of action. Such products include:
Recently the drug has been used in marine reef aquaria to control parasitic harptacoid copepod (Tegastidae) infestations on captive hard coral colonies. It is an effective full tank treatment for these parasites because it is not toxic to corals in the dosage required to kill the parasites. Shrimps, crabs and other crustaceans should be removed prior to treatment, as they will be killed by the treatment.
, tremor
and ataxia
.
Milbemycin
The milbemycins are a group of macrolides chemically related to the avermectins and were first isolated in 1972 from Streptomyces hygroscopicus.They are used in veterinary medicine as antiparasitic agents against worms, ticks and fleas....
s, used as a broad spectrum antiparasitic. It is active against worms (anthelmintic
Anthelmintic
Anthelmintics or antihelminthics are drugs that expel parasitic worms from the body, by either stunning or killing them. They may also be called vermifuges or vermicides .-Pharmaceutical classes:...
), insects (insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
) and mites (miticide
Miticide
Acaricides are pesticides that kill members of the Acari group, which includes ticks and mites.Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields.-Terminology:...
).
Mechanism of action
Like avermectinAvermectin
The avermectins are a series 16-membered macrocyclic lactone derivatives with potent anthelmintic and insecticidal properties. These naturally occurring compounds are generated as fermentation products by Streptomyces avermitilis, a soil actinomycete...
s, milbemycins are products of fermentation
Fermentation (biochemistry)
Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...
by Streptomyces
Streptomyces
Streptomyces is the largest genus of Actinobacteria and the type genus of the family Streptomycetaceae. Over 500 species of Streptomyces bacteria have been described. As with the other Actinobacteria, streptomycetes are gram-positive, and have genomes with high guanine and cytosine content...
species. They have a similar mechanism of action, but a longer half-life than the avermectins. Milbemycin oxime is produced by Streptomyces hygroscopicus aureolacrimosus. It opens glutamate sensitive chloride channel
Chloride channel
Chloride channels are a superfamily of poorly understood ion channels consisting of approximately 13 members.Chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell...
s in neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s and myocyte
Myocyte
A myocyte is the type of cell found in muscles. They arise from myoblasts.Each myocyte contains myofibrils, which are long, long chains of sarcomeres, the contractile units of the cell....
s of invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s, leading to hyperpolarisation
Hyperpolarization (biology)
Hyperpolarization is a change in a cell's membrane potential that makes it more negative. It is the opposite of a depolarization.Hyperpolarization is often caused by efflux of K+ through K+ channels, or influx of Cl– through Cl– channels. On the other hand, influx of cations, e.g...
of these cells and blocking of signal transfer.
Uses
Milbemycin oxime is active against a broad spectrum of nematodes, although it is less potent against heartwormHeartworm
Heartworm is a parasitic roundworm that is spread from host to host through the bites of mosquitoes. The heartworm is a type of filaria, a small thread-like worm. The definitive host is the dog but it can also infect cats, wolves, coyotes, foxes and other animals, such as ferrets, sea lions and...
s than ivermectin. Its miticide spectrum includes Sarcoptes
Sarcoptes scabiei
Sarcoptes scabiei or the itch mite is a parasitic arthropod that burrows into skin and causes scabies. Animals affected include not only human but also wild and domesticated dogs and cats in which it is one cause of mange...
and Demodex. The USA FDA approval for milbemycin oxime as formulated alone does not indicate insecticidal activity.
The substance is often combined with other parasiticides to achieve a broader spectrum of action. Such products include:
- Milbemax (with praziquantelPraziquantelPraziquantel is an anthelmintic effective against flatworms. Praziquantel is not licensed for use in humans in the UK; it is, however, available as a veterinary anthelmintic, and is available for use in humans on a named-patient basis....
) - Sentinel Flavor TabsSentinel Flavor TabsThe combination milbemycin oxime/lufenuron is a parasite control drug in which the active ingredient, milbemycin oxime, eliminates fleas and worms, while a second active ingredient, lufenuron, arrests the development of eggs and larvae, preventing them from maturing and continuing the infestation...
(with lufenuronLufenuronLufenuron is the active ingredient in the veterinary flea control medication Program, and one of the active ingredients in the veterinary flea control, heartworm prevention, and anthelmintic medicine milbemycin oxime/lufenuron .Lufenuron is stored in the animal's body fat and transferred to adult...
)
Recently the drug has been used in marine reef aquaria to control parasitic harptacoid copepod (Tegastidae) infestations on captive hard coral colonies. It is an effective full tank treatment for these parasites because it is not toxic to corals in the dosage required to kill the parasites. Shrimps, crabs and other crustaceans should be removed prior to treatment, as they will be killed by the treatment.
Side effects
The drug is tolerated well, even by dogs with multiple drug resistance. In high doses, it can cause side effects like stuporStupor
Stupor is the lack of critical cognitive function and level of consciousness wherein a sufferer is almost entirely unresponsive and only responds to base stimuli such as pain. This is often mistaken for delirium and treated with Haldol and or other anti-psychotic drugs...
, tremor
Tremor
A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the...
and ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
.