I also took ibuprofen, full dose for just 48 hours on a plane journey as I'd hurt my back just beforehand. It triggered gastritis in me, inflammation of the stomach lining, that landed me in a&e and took 4 months to heal. It can irritate the lining to the point of causing stomach ulcers, my brother in law who is a doctor told me that. If you do take it, make sure it's always after food and never on an empty stomach, lowest dose possible for shortest amount of time. I'd never touch the stuff again.
What I've often wondered tho (and again too scared to try now) is whether topical ibuprofen like voltarol gel for muscle problems, would also cause issues. I'm assuming not as it bypassed digestive system but too nervous to try.