With any of those medications - you are not preventing tics/fleas/etc from getting on your dog. You are, however, making your dog unappealing to them once they're on. You should either find dead fleas/tics which can be brushed off, or none.
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I second the advice to check out Nothing In Life Is Free training. It's a really great way to get a handle on this situation now, and get your dog under your control rather than it's own. A few links for it are:

I have had great reactions from all my pets that have been put on it for various joint issues as they age.

Why wouldn't you go ask for the dog back? Of course you should.

A racist is someone who believes that the color of a person's skin defines things about their character as a person. Your own statements show you to be someone who believes that race defines their character. You, ma'am, are a racist by the exact...