I took mefenamic acid 4 hrs ago for my toothache but it didn't help, is it okay to take ibuprofen instead?

Wait: It is not unusual that the first dose of a pain medication will not provide adequate pain relief. A therapeutic blood level must be reached before it is effective which could take 2-3 doses. Since you are due to take another dose 6 hours after your first dose, I would suggest trying to wait until then and giving it a chance to work. You don't want to prematurely jump from one pain med to another.

Yes.: Yes. Depends on dose but, seeing your DDS is solution.