Took 1 motrin 800 3 hours ago, is it safe to take 1-2 tablets of excedrin migraine?

Not a good combo: Too many drug interactions. Ask your treating doctor for a different migraine abortive (ex. Imitrex). Hope it helps.

Yes, but...: I wouldn't do that. You've taken a large dose of ibuprofen, and you should not take any more for 8 hrs from the last dose. Now, the drug you've mentioned has a small amount of aspirin, of generic tylenol, (acetaminophen) and of caffeine. Doubt it enhance your major dose of ibuprofen. You can repeat the Motrin at 8 hrs, but if your headache is that severe you should seek some guidance from your doctor. Good luck.