For breeds determined to be sensitive to ivermectin, an alternative to daily oral
treatment with an ivermectin derivative, Milbemycin, is also acceptable.
Frequency of the mutant MDR1 allele
associated with ivermectin sensitivity in a sample population of collies from the northwestern United States.
OBJECTIVE: To determine the frequency of the MDR1 gene mutation (polymorphism) associated
with ivermectin sensitivity in a sample population of Collies in Washington and Idaho.
A mild hypersensitivity - type reaction, presumably due to dead or dying microfilariae and particularly involving a transient diarrhea, has been observed in clinical
trials with ivermectin after treatment of some dogs that have circulating microfilariae.
This was not as good a result
as with the ivermectin products because ivermectin is better at killing older heartworm larvae.
This does not mean that pet owners should experiment
with ivermectin doses on their own as there is some potential for lethal toxicity if this drug is not used appropriately.
Unfortunately, treatment failures have been known to
occur with ivermectin so rather than risk one cat being able to re-infect the whole lot because of a treatment failure, it is best to go with dipping if at all possible.
Studies with ivermectin indicate that certain dogs of the Collie breed are more sensitive to the effects of ivermectin administered at elevated dose levels (more than 16 times the target use level) than dogs of other breeds.
SAFETY: Studies
with ivermectin indicate that certain dogs of the Collie breed are more sensitive to the effects of ivermectin administered at elevated dose levels (more than 16 times the target use level of 6 mcg / kg) than dogs of other breeds.
If milbemycin is inadvertantly given to a dog with active heartworm infection, the microfilariae are killed much faster than
with the ivermectin products.
In the 1988 experiment by Atwell, dogs who went off heartworm preventive for four months and then
restarted with ivermectin had 95 % fewer adult heartworms than dogs who went without ivermectin, though it should be noted that some heartworms were still able to establish infection.
This does not mean that a pet owner should
experiment with ivermectin doses on their own as there is some potential for lethal toxicity if this drug is not used appropriately.
On SD 0, the dogs assigned to Group 1 were treated
orally with ivermectin / pyrantel pamoate chewable tablets, Group 2 dogs were treated orally with milbemycin oxime flavored tablets, Group 3 dogs were treated with selamectin topical solution, and Group 4 dogs were treated with imidacloprid / moxidectin topical solution.
Researchers from Kenya and the United Kingdom report that dosing
people with ivermectin, commonly used in heartworm pills, makes them deadly targets for the...
The capsule contains polymers and other materials
mixed with ivermectin to allow the drug to slowly diffuse out of the material over time.
The antibiotic doxycycline, which kills a bacterium called Wolbachia that lives symbiotically with the worm, has shown promise in killing adult worms as well and is sometimes used alone or in
combination with ivermectin.
Current control strategies rely on the repeated mass treatment of potential
patients with ivermectin, however, as diagnosis is often difficult.
«Low» shedders only need to be dewormed twice per year (spring and fall)
with an ivermectin class dewormer (Equimax, Equalvan, Quest, Ivermectin, etc.).
However, the current recommendation stands regarding
pre-treating with Ivermectin for two months to kill the microfilariae before treating with melarsomine to kill adult worms.
In the past, low - risk dogs diagnosed as Class I could instead be treated long -
term with ivermectin - based heartworm preventive products usually in a pill form.
In dogs, the risk of side effects associated
with ivermectin depends on the dosage, on the susceptibility of the individual dog and on the presence of heartworm microfilaria (a larval form of the heartworm.)
It has become clear that after keeping this parasite at
bay with ivermectin, it is no longer as effective a drug as it once was.
A study on the prevention of prenatal and galactogenic Toxocara canis infections in pups by treatment of infected
bitches with ivermectin or doramectin... more
This means that if you opt to treat a heartworm positive dog
only with an ivermectin heartworm preventive, you can expect the dog to remain heartworm positive for as long as two years and the heartworm disease will be progressing during those two years.
It says, «Studies have shown that heartworm - positive dogs
pretreated with ivermectin and doxycycline prior to receiving melarsomine (Immiticide) injections had less pulmonary pathology associated with the death of the heartworms.
The product is typically used every 2 - 4 weeks to treat demodicosis and has the advantage of being safe for the collie - type breeds (and other
individuals with ivermectin sensitivity).
A mild hypersensitivity - type reaction presumably due to dead or dying microfilariae, particularly involving a transient diarrhea, has been observed in clinical trials
with ivermectin alone after treatment of some dogs that have circulating microfilariae.
As with ivermectin, milbemycin oxime will rapidly kill heartworm larvae and potentially lead to shock so it is important to test dogs that are old enough to have a heartworm infection prior to use.
Pharmacologic
treatment with ivermectin, loperamide, vincristine, and other drugs that are substrates of P - glycoprotein, the MDR1 gene product, may result in neurologic toxicosis in a high percentage of Collies.
In clinical field
trials with ivermectin / pyrantel, vomiting or diarrhea within 24 hours of dosing was rarely observed (1.1 % of administered doses).