Too much dewormer?

Question
Hi, thanks for taking the time to view my question!
I am concerned that we gave our pup too much dewormer.  Here's the story: On Sunday, we found our dog with poop all over the crate.  Upon cleaning, my husband discovered roundworms.  I bought Sentry WormXPlus and gave him one dose which had 114mg pyrantel.  He is a 6 month old boxer who weighs about 40lbs.

My husband, not asking beforehand, thought he had to give the dog another dose on Monday morning.  There enters an additional 114mg pyrantel.  Fast forward 5 hours and there's another mess, this time I had to clean up.

I went to the vet to get him Heartgard Plus since I read it kills roundworms.  Since he's 40lbs, they said it was okay for me to give him a dose for 51-100lb dogs that day, Monday.  That was an additional 227mg of pyrantel.

So my 6 month old, 40lb boxer had 455mg of pyrantel in 24 hours.  It just dawned on me now that this is probably bad.  Not emergent but still concerning.  Do you think he will be okay aside from just diarrhea for a couple days?  He's not dehydrated, and he's still eating.  The stools are malodorous and impossible to pick up, there is no solidity whatsoever in the stool.  I would say it's almost like a gush.  Please excuse the graphic nature of the description, but I have to be clear about it!

Your opinion would be appreciated!

Answer
Pyrantel is a fairly safe wormer. He will probably only get diarrhea from it but if he starts vomiting or shaking, or stops eating, then you should see a vet right away.

Let it clear out of him and just give him his Heartgard monthly. That will keep him worm free!