Because of the expense
of melarsomine treatment as well as the risks involved, some owners and humane groups decide to simply place heartworm - posative dogs that are not showing symptoms on ivermectin and doxycycline antibiotic.
Dogs that have undergone adulticidal therapy in preparation for relocation should not be transported for at least 4 weeks after
melarsomine injection.
Once the immature parasites have been treated, the adult worms are killed with a series of two or three treatments of a worm - killing poison
called melarsomine dihydrochloride.
The myth that the «slow kill» method is «just as good»
as melarsomine therapy may have originated in McCall and colleagues» 2001 study.5 This study demonstrated that 30 months of ivermectin at preventive doses reduced 7 - month - old worms by 94 % and 8 - month - old worms by 56 %.
Administering doxycycline and a macrocyclic lactone during the 1 - month rest period after
melarsomine administration eliminates most of the remaining circulating microfilariae, and any remaining adult worms are essentially sterile and die of attrition over time.
However, the use of ivermectin / pyrantel pamoate is seldom a substitute
for melarsomine treatment because the slow kill may allow pulmonary pathology to progress in the interim.
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.
For dogs that are still in relatively good health, I still believe that the traditional 3 -
dose melarsomine treatment is usually the best option.
Infection often is lethal, and a safe and effective
melarsomine protocol has not yet been developed.
Administration of local anesthetics prior to injection is not recommended as these treatments carry their own risk of discomfort and can interfere with
proper melarsomine injection.
In cases
where melarsomine treatment is not practical for a dog with heartworms, monthly ivermectin is preferable to no treatment.
It may also occur when the younger stages of heartworms, those not readily killed
by melarsomine, went on to mature in the pet.
, os., for 20 days) followed by a treatment with the arsenic
adulticide melarsomine (Immiticide, Merial, 2.5 mg / Kg, im., twice, q. 24 hours) and the microfilaricide drug ivermectin (Ivomec, Merial, 50 m / Kg, sc., once) given ten days after the treatment for the macrofilariae.
Our vet is following the American Heartworm Society Guidelines, so she is slated to have her
first melarsomine shot in late August and the others in late September.
Strict confinement is essential during the heartworm treatment period and for at least one month following the
last melarsomine injection.
Both the
standard melarsomine protocol and the alternate regimen kill all or most worms in ~ 75 % of dogs.
Stabilizing treatment variably includes cage confinement, oxygen, corticosteroids, and heparin (75 - 100 U / kg, SC, tid) for 1 wk prior to the
alternate melarsomine treatment protocol.
Both manufacturers of
melarsomine suggest a 3 - dose, spread out administration protocol and strict post-treatment exercise restriction for high - risk dogs (4 - 6 wks of low - stress cage confinement).
There were periods of time when Immiticide ®, the
Merial melarsomine product, was unobtainable.
Mild infection, a weakly positive antigen test, absence of clinical signs, advanced age, and a sedentary dog are factors that may negate the need for a
repeat melarsomine treatment.
The dog is typically hospitalized overnight and is given a
third melarsomine injection the next day.
There are situations in
which melarsomine treatment can not be pursued due to other health issues.
Thirty days later, the dog returns to the hospital and a
second melarsomine (Immiticide) injection is given.
Heart worm adulticide
i.e. Melarsomine Dihydrochloride is the only effective way to treat heart worm in dogs.
This problem is partially mitigated by
giving melarsomine over a 2 day period of time instead of all at once.
Why is
melarsomine recommended by the American Heartworm Society (AHS), given the potential for complications during adulticide treatment?
Can we treat dogs with two injections of
melarsomine instead of three to get them out of the shelter faster?
The most commonly used dog heartworm treatment is the medication Immiticide (
melarsomine hydrochloride) which is injected into the back muscles of dogs suffering from class 1 - 3 heartworm.
If doxycycline is incorporated into a heartworm treatment protocol it should be given before administration of
melarsomine so the Wolbachia organisms and their metabolites are reduced or absent when the worms die and fragment.
It is
called melarsomine dihydrochloride and it is marketed as Immiticide by Merial Pharmaceutical Company.
b. Dogs that have been treated with
melarsomine dihydrochloride should not be transported for at least 4 weeks after an injection to minimize stress and physical exertion that accompany the relocation process.
Heartworm positive dogs can be treated
with melarsomine dihydrochloride, a drug containing arsenic.
Following melarsomine injection, exercise must be severely restricted for 4 - 6 wk to minimize thromboembolic lung complications.
Even when these guidelines are followed to the letter, some dogs are not entirely cleared of heartworms by the two - dose or three -
dose melarsomine treatment.
Immiticide, also known
as melarsomine, is administered through injections given over a several month period.
Here are some of the heartworm treatment side effects filed with the Food and Drug Administration (FDA)
on melarsomine.
(ref) That can put
proper melarsomine treatment beyond the capacity of many pet owners, most humane societies and most in the developing world to pay for it.
I adopted a malamute who was heartworm positive and we just did the
first melarsomine injection this morning.
For instance, a treatment protocol in which 2
melarsomine injections are administered as described in the product insert decreases total adult worm numbers by 90 % and male worm numbers by almost 100 %.