Has anyone had any experience with drug resistant heartworms? It appears that Lexy may have them - we've sent samples out for testing - but we won't have results til next week.
I was hoping someone here might have some info.[/b]
To date, there is no evidence of avermectin/milbemycin resistance in D. immitis, also a filarial nematode. Chemotherapy against trichostrongylids of animals, human filariae, and D. immitis, relies on avermectins or milbemycins. However, control involves targeting different stages or processes in the nematode life cycles, different control strategies, different proportions of the nematode population in refugia, and different drug dosage rates. Consideration of the proportion of the D. immitis population normally in refugia, the life cycle stage targeted, and the anthelmintic dosages used suggest that it is unlikely that significant avermectin/milbemycin resistance will be selected in D. immitis with current treatment strategies.[/b]
Howeever capasolate is not the standard treatment and has not been for quite a few yearsThe first step in ridding a dog of the parasites is to administer a chemical to kill the adult worms. Capasolate (Arsenamide, Thiacetarsamide), and Immiticide R (Melarsomine, dihyrdochloride) are arsenical compounds used to kill adult heartworms in both dogs and cats. These compounds are given as an intravenous injection and one or two doses are given each day for two days followed by restriction of physical activity for one to two months. As the worms die they are carried by the bloodstream to the lungs. One dog in twenty may be expected to die as a result of complications from this therapy. There are fewer complications with cats. Adult female worms and immature forms are somewhat resistant to Capasolate and, consequently, this drug may be less than 100 percent effective.[/b]
keep in mind this is not the most recent quidlines but AHS no longer felt compled to mention capasolate in the 2005 guidlines http://www.heartwormsociety.org/article.asp?id=48[/urlThe organoarsenical adulticide, melarsomine, is less toxic and more effective than its predecessor, thiacetarsamide, which is no longer commercially available[/b]
hookworms differ from hearworm in the regard to resistancei have friend whose dog seems to have drug resistant hookworms, but not heartworms...so far they are just giving him higher doses of meds to see if it works, but he's been treated for them for about 3 months now.[/b]