I would go with
Heartguard Plus to be honest...it's a monthly heartworm prevention, actually - but the "Plus" version also treats both hookworms and roundworms.
...I wouldn't keep pumping them with the other meds, even if they are prescribed by a vet. If they keep getting sick and feeling punky after every dose, that would be enough to make me stop giving it to them.
We haven't had a problem with Heartguard Plus with regard to feeling ill or side effects.
If your dogs are already on Heartguard, it's as simple as switching to Heartguard Plus (but NOT if they've been treated with other similar meds in recent days, as that would be too much for their little systems).
If your dogs aren't on Heartguard at all, then you'll need a heartworm test to come back negative first, and then begin the Heartguard Plus.
Just my two cents and I'm not an expert.
