I rescue and the group only does immiticide back to back. Rarely they do the immiticide 30 days apart. If it were my dogs, I think I would opt for slow kill. Has your vet staged the heartworm disease? In the early stages with a small amount of worms, it’s less stressful on the dog, but still dangerous none the less. I’ve had 4 dogs in 4 years die from complications of heartworm treatment (pulmonary embolism). One is at the vet right now with complications. If you use topical flea/tick/mosquito meds, you can still also use essential oils like Sentry Natural Defense and Halo Herbal Dip.
http://healthypets.mercola.com/sites/healthypets/archive/2011/11/22/cheaper-safer-therapy-for-heartworm.aspx
