Motrin (Ibuprofen) Central nervous system agent Analgesic Primary dysmenorrhea, mild to moderate pain, fever reduction, acute pain, Osteoarthritis, Rheumatoid Arthritis, headache, menstrual cramps, muscle ache. (Adults) Arthritis: 1200 to 3200 mg/day in divided doses. Use smallest effective dose. Max 3200 mg/day. Mild to moderate pain: 400 mg every 4 to 6 hours as needed, take with food. Category B. Most common: nausea heartburn, Diarrhea, abdominal pain or cramps, Constipation, Bloating, gastrointestinal bleeding, Tinnitus, azotemia, anemia, agranulocytosis, elevated enzymes, bronchospasm. Pregnancy Risk Categories defined: A: Studies in pregnant women failed to show a risk to the fetus in the first trimester - with no evidence of risk in the later trimesters. B: Animals studies indicate no adverse effect to the fetus, but there are no adequate, clinical studies in pregnant women. C: Animal studies have shown an adverse effect on the fetus, but there are no adequate, clinical studies in humans. Despite potential risks, the drug may be useful in pregnant women. D: There is evidence of risk to the human fetus, but the potential benefits of use in pregnant women may be acceptable, despite potential risks. X: Studies in animals or humans show fetal abnormalities, or adverse reaction reports indicate evidence of fetal risk. Warning: the risks involved clearly outweigh any potential benefit from using the drug in pregnant women, regardless of trimester. NR: Not rated (i.e., no information available at this time as to the potential risks or benefits).