I believe that the prescription ibuprofen is the same as the OTC, except it's more concentrated/higher dosage. Basically, OTC has 200mg and prescription strength has 800mg, so taking four tablets OTC is the equivalent of one tablet prescription. The prescription dose has all of the same digestive and kidney complications as taking more than the recommended OTC dosage, but it's generally considered better not to advise taking higher than advised dosages of easily accessible medications because I guess they fear that increases the likelihood of future abuse.