Hydroxychloroquine was approved for medical use in the United States in 1955.[1] It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system.[6] The wholesale cost in the developing world is about US$4.65 per month as of 2015[update], when used for rheumatoid arthritis or lupus.[7] In the United States the wholesale cost of a month of treatment is about US$25 as of 2020[update].[8] In the United Kingdom this dose costs the National Health Service about £5.15.[9] In 2017, it was the 128th most prescribed medication in the United States with more than five million prescriptions.[10]