Yes, heartworms are very scary - take Dr. Kemmerer's article seriously.  I
have not had much luck with the chewable tablets personally.  Some of my
ferrets refused to eat them, most ignored them, and one wanted to eat all
of them.  To better control dosages, Dr. Kemmerer mixes me up a liquid
ivermectin solution and once a month I administer a dosage based on weight
with an oral syringe.  It's easy, fast, and effective.
 
Revolution has not been specifically tested or approved for ferrets (but
neither has Frontline or Advantage).  Also, it controls for a whole host
of other pests and parasites that ferrets don't necessarily get.  In my
opinion, why put poisons in my ferret's body that are not needed?  We
simply don't know what the side effects are.
 
- Erika and the Terrific 10
[Posted in FML issue 2985]