Well I have been using ibuprofen for a really long while now because I get migraine attacks every now and again. My doc told me that I can take a maximum of 800 mg per dose (two 400mg pills) and a 3200 mg per day. i.e. u can take it with 6 hours difference in between. Following this strict schedule has proven NO Side effects (long or short term) whatsoever. It is also NOT addictive physically or physiologically on the contrary to common stereotypes. Other addictive pain killers have a hydrocodone which is a synthetic opioid and that's why they are addictive. But ibuprofen is a NSAID (Non steroidal anti inflammatory drug) means having no steroid being non addictive. Older adults though should take as little ibuprofen as possible due to higher risk of kidney and gastrointestinal side effects.