Hydroxychloroquine (HCQ), sold under the brand name Plaquenil among others, is a medication used for the prevention and treatment of certain types of malaria. Specifically it is used for chloroquine-sensitive malaria. Other uses include treatment of rheumatoid arthritis, lupus, and porphyria cutanea tarda. It is taken by mouth.
Common side effects include vomiting, headache, changes in vision and muscle weakness. Severe side effects may include allergic reactions. It does not appear to be safe during pregnancy. Hydroxychloroquine is in the antimalarial and 4-aminoquinoline families of medication.
Hydroxychloroquine was approved for medical use in the United States in 1955. It is on the World Health Organization’s List of Essential Medicines, the safest and most effective medicines needed in a health system. The wholesale cost in the developing world is about $4.65 per month as of 2015 when used for rheumatoid arthritis or lupus. In the United States the wholesale cost of a month of treatment is about US$25 as of 2019. In the United Kingdom this dose costs the NHS about £5.15. In 2016 it was the 135th most prescribed medication in the United States with more than 4 million prescriptions
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