Hydroxychloroquine (Plaquenil) is considered a disease-modifying anti-rheumatic drug (DMARD). It can decrease the pain and swelling of arthritis. 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 the communication of cells in the immune system.
Hydroxychloroquine comes in an oral tablet. Adult dosing for rheumatic diseases ranges from 200 mg to 400 mg per day (typically 5 mg/kg, maximum 400 mg daily). In some cases, higher doses are used. It can be taken as a single daily dose or in 2 divided doses if taking more than one tablet. It is recommended to be taken with food. Symptoms can start to improve in one to two months, but it may take up to six months before the full benefits of this medication are experienced.
Hydroxychloroquine typically is very well tolerated. Serious side effects are rare. The most common side effects are nausea and diarrhea, which often improve with time. Less common side effects include rash, changes in skin pigment (such as darkening or dark spots), hair changes, 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 can cause visual changes or loss of vision. Such vision problems are more likely to occur in individuals taking high doses for many years, in individuals 60 years or older, those with significant kidney or liver disease, and those with underlying retinal disease. At the recommended dose, development of visual problems due to the medication is rare. It is recommended that you have an eye exam within the first year of use, then repeat every 1 to 5 years based on current guidelines.
Additional rare reports of changes in the heart rhythm have been reported with the use of hydroxychloroquine, particularly in combination with other medications. While monitoring for this risk is not typical in the office setting, it has been indicated in hospitalized and critically ill patients to evaluate for interactions with other medications.
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.
Updated April 2020 by Vaneet Sandhu, 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.