[kjc]

Originally Posted by Ellie May

Most heartworm meds are given monthly just for that reason.
It is easier to remember. In other words, the company gets more money this way. Not all drugs work the same though and there are some that you probably can't wait 2-3 months to give. If your dog does get heartworms, some companies will pay for treatment if you follow their protocol exactly like Heartgard. And how do they prove you didn't? These drugs only kill certain stages of larvae too, Looks to me like it's stage L4, which is 2-3 months so it is important that your vet is in agreement and helping you come up with a different schedule. I am going to be talking to Ellie's vet about the grace period of Interceptor and I may stop giving it monthly. I think Heartgard's is said to be 15 days.The first dose should be administered within one month of the dog's first exposure to mosquitoes and monthly thereafter until the end of the mosquito season. If a dose is missed and a 30-day interval between dosing is exceeded, administer INTERCEPTOR Flavor Tabs immediately and resume the monthly dosing schedule.L3's are readily killed by Interceptor but not by Heartgard30. Interceptor and Heartgard30 both act primarily on the L4's living in the skin. After a dose of either medication, any L4's present will be wiped out. Heartgard30 is also able to kill the younger L5's.

By the way, there are a lot of reports about Revolution failing and dogs getting heartworms anyway while on it...

Haven't seen any to date...

Selamectin, the active ingredient in Revolution, is a macrocyclic lactone compound. These compounds effectively prevent the development of adult heartworms when administered to dogs and cats within one month of exposure to infective (L

3) Dirofilaria immitis larvae. Efficacy of acrocyclic lactones decreases below 100% in dogs, however, if first administered >2 months after exposure to infective larvae. Thus, in heartworm endemic regions, delaying initiation of heartworm prevention using Revolution beyond 2 months of first exposure to infective larvae (e.g., starting puppies and kittens at >8 weeks of age), or gaps of >2 months in the administration of Revolution during periods of heartworm transmission, increases the risk of the animal acquiring heartworms.

Found a good link from a rescue group:

http://www.greatlakesbcrescue.org/He.../Heartworm.htm

My Point (not to be arguementative or anything) None of the literature says OMG you missed a dose, go get tested, your pup will need treatment. It does say (on specific drugs mentioned) A gap Greater than 2 months from the time of exposure may lead to microfilaria... and they still don't say run to the vet....they said resume your dosing schedule??? I think it's propaganda to scare us into spending bucks. How much does the whole Heartworm industry pull in in a year? Tons of $$$$

BTW: some material I c&p from the info or FDA reports found online.