Get our free Motrin coupon and be eligible to receive a discount. You can reduce your Motrin cost by up to 75% with our free Motrin discount card. Bring it to a participating pharmacy near you to save on your prescription medication.Treating rheumatoid arthritis, osteoarthritis, menstrual cramps, or mild to moderate pain. It may also be used for other conditions as determined by your doctor. Motrin is an NSAID. Exactly how it works is not known. It may block certain substances in the body that are linked to inflammation. NSAIDs treat the symptoms of pain and inflammation. They do not treat the disease that causes those symptoms.