# 45 day Interceptor



## Mel's chi's (Jun 2, 2011)

I have been dosing the Interceptor once a month as per their & vets instructions. I need to keep them dosed year round living in a tropical region ( icky Mosquitos!). I was wondering where the 45 day dosing schedule came from?  If I could dose less, but still year round that would be great! Thanks ahead for your advice!!


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## Christabelle (Dec 21, 2011)

A lot of people dose every 45 days and some vets say
that the monthly schedule was more for helping Owners
remember and that every 45 days is fine. Lots of rescues
also do 45 days because it helps out financially.

Because we have so so so many mosquitos in the
summer months I am diligent about 30 day cycles. However
in the colder months and I get a few more cold days up here
than you do down there :coolwink: I stretch it to 45 because
mosquitos aren't as abundant.


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## elaina (Jul 1, 2008)

i think very important to make sure you do not go over the 45 days


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## Mel's chi's (Jun 2, 2011)

Christabelle said:


> A lot of people dose every 45 days and some vets say
> that the monthly schedule was more for helping Owners
> remember and that every 45 days is fine. Lots of rescues
> also do 45 days because it helps out financially.
> ...


Thanks for the clarification  I hate to dose so much but the mosquito issue here just isn't worth the risk, especially in this years hot winter! There aren't a lot, but there still present!:foxes15:


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## Brodysmom (Jan 8, 2009)

I'll try to find the studies for you Mel. They prove that the heartworm meds last 60 days, but most people forget. So they made them "monthly" to make it easier for people to remember. The 45 days was a compromise between the monthly and the 60 day schedule. I'm in a hotel out of town on a shaky connection, but I promise I'll find the studies that back this up when I can.


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## Mel's chi's (Jun 2, 2011)

Brodysmom said:


> I'll try to find the studies for you Mel. They prove that the heartworm meds last 60 days, but most people forget. So they made them "monthly" to make it easier for people to remember. The 45 days was a compromise between the monthly and the 60 day schedule. I'm in a hotel out of town on a shaky connection, but I promise I'll find the studies that back this up when I can.


Hi Tracy, were you able to locate a reliable study on the 60 day schedule? Just curious... Thanks!


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## Brodysmom (Jan 8, 2009)

I don't see the actual study I had bookmarked, but here are the FDA approval study results for the major heartworm medications. (You might be able to find the actual FDA data if you look). This information is straight from the horses mouth. It says right on the insert that the *product is effective for 60 days (simulating a missed dose).*

From dogaware: DogAware.com Articles: Heartworm Prevention in Dogs

The monthly dosage schedule was devised to make it easy for people to remember when to administer the drugs, and to ensure that dogs would still be protected if a dose were somehow not swallowed or later vomited before being absorbed.

The FDA approvals cite studies showing that Heartgard, Interceptor and Revolution provide protection beyond 30 days. If you are very good about remembering to give medications, and you can watch your dog after administering the pill to be sure that it is not spit out or later vomited, it may be safe to use heartworm preventatives less frequently than every 30 days. Dosing your dog every 45 days is a conservative way to stretch your dog's dosage schedule.

The original FDA approval for *Heartgard* states, “The target dose of 6 mcg per kilogram of bodyweight was selected from titration study 10855 as the lowest dose providing 100% protection when the dosing interval was extended to *60 days* to simulate a missed-dose circumstance.”

The original FDA approval for *Interceptor* states, “Complete (100%) protection was achieved in dogs treated at 30 days post infection, with 95% protection at *60 and 90 days*.” This does not apply to Safeheart, which was tested only at a 30 day dosing interval.

The original FDA approval for *Revolution* states, “Selamectin applied topically as a single dose of 3 or 6 mg/kg was 100% effective in preventing the maturation of heartworms in dogs following inoculation with infective D. immitis larvae 30 or 45 days prior to treatment, and 6 mg/kg [the recommended dosage amount] was 100% effective in preventing maturation of heartworms following inoculation of infective larvae *60 days* prior to treatment.”

I think its important to point out that all these drug companies are ASSUMING an infected dog. The studies are done by injecting heartworm larvae into the test/research dogs. They then conduct studies on the dogs with the meds to see how they can kill the heartworms before they overtake and kill the dog. 

Heartworm medication KILLS heartworm larvae that are present in the dog. *THEY DO NOT PREVENT ANYTHING* except the growth of the heartworm to an adult. They don't prevent the dog from actually CONTRACTING the heartworms. 

So when you dose your dog, you are giving the meds to KILL heartworms. _You are not preventing them from infecting your dog. _ The meds work when the infection has already happened. I think many many people misunderstand this concept.


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