There are so many opinions/data out there as what should be used and what can be used for heartworm prevention and parasite control in our Breed.
I have been using Sentinel spectrum for the past two years on all of our dogs and puppies. We use it year round once a month every month... pregnant, not pregnant, nursing...all get it. We have not experienced any adverse side effects as of today on any of our dogs. I have also had a fecal done when it was due to give the monthly dose with all clear results. So it is taking care of all parasites in our dogs as well.
Do I recommend you use it... I recommend you use what works for your dogs.
There are a list of drugs that you need to AVOID but aside from those find what works for your dog(s).
Be AWARE of what drugs are on the MDR1 list (regardless of your dogs MDR1 status)treat all your dogs as they are MDR1 positive because it is known that negative dogs have had adverse effects while taking medications on that list.
Copied from Washington State University website Multidrug Sensitivity in Dogs Many herding breed dogs have a genetic predisposition to adverse drug reactions involving over a dozen different drugs. The most serious adverse drug reactions involve several antiparasitic agents (ivermectin, milbemycin and related drugs), the antidiarrheal agent loperamide (Imodium), and several anticancer drugs (vincristine, doxorubicin, others). http://vcpl.vetmed.wsu.edu/problem-drugs