The first thing we need to do is to get your pup to vomit up the pills he ate. The way to make that happen is pretty easy and instructions can be found here:
Once you've induced vomiting, you'll need to monitor your pup for signs of trouble: Fast heart rate, vomiting, nausea (your dog will most likely lick lips a lot and look like he wants to vomit), increased panting and increased thirst are all signs that your dog needs to be seen by the nearest emergency clinic.
If you've gotten the pills out before they've dissolved too much, you can most likely just monitor your dog for tonight, but I would absolutely call your regular vet in the morning and see if they think he needs to be seen.
If the pills are already dissolved (meaning you don't see any whole pills in the vomitus) or you can't get your dog to vomit, then you have to get to a vet tonight so that they can help get the pills out of the stomach.
I hope this helps