Hydroxychloroquine (Plaquenil)
Hydroxychloroquine (Plaquenil) is a disease-modifying anti-rheumatic drug (DMARD). It can decrease the pain/swelling from arthritis and prevent joint damage. Hydroxychloroquine was first used to prevent and treat malaria but was found to have benefits in autoimmune diseases, like lupus and other conditions. The mechanism of action of hydroxychloroquine is not clear, but it is thought to interfere with communication in the immune system.
How To Take It
Hydroxychloroquine comes in an oral tablet. Adult dosing for rheumatic diseases ranges, typically, from 200 mg to 400 mg per day (typically 5 mg/kg, maximum 400 mg daily). It can be taken as a single daily dose or in 2 divided doses. It is recommended to be taken with food to prevent gastrointestinal side effects. Symptoms can improve in one to two months, but it can take up to six months for the full benefits of this medication.
Side Effects
Hydroxychloroquine typically is well tolerated. The most common side effects are nausea and diarrhea, which often improve with time. Other side effects include rash, hair changes, and muscle weakness. Rarely, hydroxychloroquine can lead to anemia, typically in individuals with G6PD deficiency or porphyria.
In rare cases, hydroxychloroquine can cause visual changes or loss of vision. Such 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, the development of visual problems is rare. It is recommended that you have an eye exam within the first year of use, then repeat every 1 to 5 years.
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.
Tell Your Rheumatology Provider
Although there are few drug interactions with hydroxychloroquine, be sure to tell your rheumatology provider about all medications you are taking, including over-the-counter drugs and natural remedies.
Be sure to notify your other providers when taking this drug. This drug is not known to suppress your immune system. Obtain vaccines recommended for healthcare maintenance after discussion with your doctor. Notify your eye doctor when on this medication so regular visual screening tests can be performed. If you are pregnant, considering becoming pregnant, or lactating, please discuss with your rheumatology provider that you are taking this medication. Hydroxychloroquine has been shown to be safe during pregnancy and breastfeeding.
Updated March 2025 by Rebecca Fitzpatrick, 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 healthcare provider for professional medical advice, diagnosis, and treatment of a medical or health condition.