Rheumatic disorders

Hydroxychloroquine (HCQ), sold under the brand name Plaquenil among others, is a medication used for the prevention and treatment of certain types of malaria.^[1] Specifically it is used for chloroquine-sensitive malaria.^[2] Other uses include treatment of rheumatoid arthritis, lupus, and porphyria cutanea tarda.^[1] It is taken by mouth.^[1]

Common side effects include vomiting, headache, changes in vision and muscle weakness.^[1] Severe side effects may include allergic reactions.^[1] It does not appear to be safe during pregnancy.^[3] Hydroxychloroquine is in the antimalarial and 4-aminoquinoline families of medication.^[1]

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.^[4] The wholesale cost in the developing world is about $4.65 per month as of 2015 when used for rheumatoid arthritis or lupus.^[5] In the United States the wholesale cost of a month of treatment is about US$25 as of 2019.^[6] In the United Kingdom this dose costs the NHS about £5.15.^[7] In 2016 it was the 135th most prescribed medication in the United States with more than 4 million prescriptions

Hydroxychloroquine treats malaria, systemic lupus erythematosus, rheumatic disorders like rheumatoid arthritis, porphyria cutanea tarda, and Q fever.^[1]

In 2014, its efficacy to treat Sjögren syndrome was questioned in a double-blind study involving 120 patients over a 48-week period.^[9]

Hydroxychloroquine is widely used in the treatment of post-Lyme arthritis. It may have both an anti-spirochaete activity and an anti-inflammatory activity, similar to the treatment of rheumatoid arthritis