it'll probably be by weight, so, you'll most likely have to go to the office. Depending on the Vet, they may be willing to go for it without an exam.
Any of the OTC wormers I've seen here are, -pardon-, crap, and I wouldn't waste my money on them. (and I used to work in a pet store myself)
In my experience when there was question as to weather or not Oscar might have a worm (never ever seen one! touch wood), we gave the wormer and then again 2 weeks later.
Oscar takes Interceptor, because we're out hiking a lot a Racoon Roundworm is nasty nasty stuff.
I can only please one person per day. Today is not your day, tomorrow doesn't look good either.
"You didn't know of the magical powers of the break stick? It's up there with genies and Harry Potter as far as magic levels go." SisMorphine 01/07/07