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Hydroxychloroquine (Plaquenil) is considered a disease-modifying anti-rheumatic drug (DMARD), because it can decrease the pain and swelling of arthritis, and it may prevent joint damage and reduce the risk of long-term disability.
Hydroxychloroquine is in a class of medications that was first used to prevent and treat malaria. Today it is used to treat rheumatoid arthritis, some symptoms of lupus, childhood arthritis (or juvenile idiopathic arthritis) and other autoimmune diseases.
It is not clear why hydroxychloroquine is effective at treating autoimmune diseases. It is believed that hydroxychloroquine interferes with communication of cells in the immune system.
Hydroxychloroquine generally is given to adults in doses of 200 mg or 400 mg per day. In some cases, higher doses can be used.
Symptoms can start to improve in one to two months, but it may take up to six months before full benefits of this medication are experienced.
Hydroxychloroquine typically is very well tolerated, and serious side effects are rare. The most common side effects are nausea and diarrhea, which often improve with time or by taking the medication with food. Less common side effects include skin rashes, changes in skin pigment (such as darkening or dark spots), hair changes (bleaching or thinning of hair) and muscle weakness.
Rarely, hydroxychloroquine can lead to anemia in some individuals. This can happen in individuals with a condition known as G6PD deficiency or porphyria.
In rare cases, hydroxychloroquine has caused visual changes or loss of vision, but such vision problems are more likely to occur in individuals taking high doses for many years, in persons 60 years or older, or in those with significant kidney disease. The dose used today is lower than the one originally used to treat arthritis or malaria. At the current recommended dose, development of visual problems while taking this medication is very unusual.
Although there are few drug interactions with hydroxychloroquine, to be safe be sure to tell your doctor about all of the medications you are taking, including over-the-counter drugs and natural remedies.
Be sure to notify your other physicians that you are taking this drug. This drug does not have a strong effect on the immune system, so vaccines recommended by other physicians are generally acceptable. Be sure to notify your ophthalmologist that you are taking this medicine so you can have the correct visual screening tests.
Updated March 2015 by Michael Cannon, MD, and reviewed by the American College of Rheumatology Committee on Communications and Marketing.
This information is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.
© 2015 American College of Rheumatology