Ibuprofen is a medication in the nonsteroidal anti-inflammatory drug (NSAID) class that is used for treating pain, fever, and inflammation. This includes painful menstrual periods, migraines, and rheumatoid arthritis. It may also be used to close a patent ductus arteriosus in a premature baby. It can be used by mouth or intravenously. It typically begins working within an hour.Common side effects include heartburn and a rash. Compared to other NSAIDs, it may have fewer side effects such as gastrointestinal bleeding. It increases the risk of heart failure, kidney failure, and liver failure. At low doses, it does not appear to increase the risk of heart attack; however, at higher doses it may. Ibuprofen can also worsen asthma. While it is unclear if it is safe in early pregnancy, it appears to be harmful in later pregnancy and therefore is not recommended. Like other NSAIDs, it works by inhibiting the production of prostaglandins by decreasing the activity of the enzyme cyclooxygenase. Ibuprofen might be a weaker anti-inflammatory agent than other NSAIDs.Ibuprofen was discovered in 1961 by Stewart Adams and initially marketed as Brufen. It is available under a number of trade names, including Advil and Motrin. It was first marketed in 1969 in the United Kingdom and in the United States in 1974. It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system. It is available as a generic medication. The wholesale cost in the developing world is between 0.01 and US$0.04 per dose. In the United States it costs about US$0.05 per dose. In 2016 it was the 35th most prescribed medication in the United States with more than 21 million prescriptions.