When my Rottie was really sick before she died, the only thing she would take pills with was ice cream..peanutbutter, cream cheese, even raw burger didn't work. When she was well, you could toss anything at her and she swallowed it whole! Ice cream let us get her meds into her and keep her comfortable til the end.
About fifteen years ago they had a flea pill called Program. We didn't have a dog then, but we did use it for cats and it worked great. It deposits in fat cells subcutaneously and the adult fleas get it when they bite, then the eggs they lay do not form properly and do not hatch. Ours were indoors and in 3 weeks we were flea free. I kept them on it a while, but it is a pesticide you are feeding your pet. Fortunately we could just keep them in the house after that.
Many years ago we had dogs and gave them brewers yeast. No fleas, but some pretty rank gas!! :lol: :lol: It seems we found some brand of food that had the yeast in it and way cheaper than flea meds. Probably safer too.
Good luck..I'm allergic to fleas and will get huge red itchy welts if bitten and the little boogers seem to love me! They're just no fun :D