Can an ibuprofen pill hurt a dog?

[BeagleMommy]

I had left a few pills of ibuprofen (200mg per pill) on my desk a day ago and just realized that one of the pills is gone and I must have accidentally knocked it on the floor. I can't find it anywhere, so it's safe to assume one of my dogs (I have two) probably found it and ate it. They eat or chew almost anything put on the floor.

They are not acting sick or depressed or have any symptoms that would lead me to believe they are not well, but I'm still worried.
Also my vet's office is closed right now. I could wait until tomorrow morning to call, of course, but I just thought I would see if anyone on Y!A knew for sure how bad this might be.

Do you think whichever dog ate the pill could be badly hurt and just not showing signs of it yet? What can ibuprofen do to a dog? I'm pretty worried so any advice would be helpful. Thanks everyone.
UPDATE:
I FOUND IT!!! LOL

I'll delete the question soon, I just wanted to let you all know. And thanks for the advice... I was going to look for an e-vet, but I wanted to do a more thorough search for the pill to make sure I wasn't getting panicked for no reason.
Thanks again everyone!

p.s. To Me and My Beagle: Yes, they are both Beagles - a girl and a boy. From the same litter. They are most certainly a handful and I don't usually do such careless things, but thankfully there's no more worries.
For today. LOL

[Keza]

The dog should be ok but i would call up the 24hr emergency vets to put yourself at ease.

[Me and my beagle]

Well if they're not displaying any signs of illness, then there's probably nothing to worry about. I would still certainly contact a vet though and discuss it with them (most of us answerers are not vets!). Maybe you could try just calling another vet in another suburb/town and getting their advice. There are 24 hour vets around...

I'm not sure how much harm ibuprofen will do to a dog, but I do know that human meds should never be given (unless prescribed by a vet).

If your dog isn't showing signs that they're unwell, then I wouldn't worry too much.

Is it a beagle you have?? I have one too who's always getting into things he shouldn't! They see everything as food!