Reviewed by: HU Medical Review Board | Last reviewed: February 2019 | Last updated: June 2021

Editor's note: Click here to read more about how hydroxychloroquine is related to the COVID-19 pandemic.

Hydroxychloroquine is a slow-acting anti-rheumatic drug (SAARD). SAARDs have traditionally been used to control inflammation in people with chronic inflammatory conditions like ankylosing spondylitis (AS) and autoimmune diseases like lupus and rheumatoid arthritis. Treatment recommendations for AS recommend against using SAARDs like hydroxychloroquine to manage AS, as there is little to no evidence for the effectiveness of SAARDs in treating AS and newer medications like TNF (tumor necrosis factor) inhibitors have demonstrated more effectiveness.1,2

Hydroxychloroquine is available as a generic medication. It is also sold under the brand name Plaquenil®.1

What is the active ingredient in hydroxychloroquine?

Hydroxychloroquine is the active ingredient in this medication. It was first used to prevent and treat malaria but has been shown to have effect in autoimmune diseases.3

How does hydroxychloroquine work?

It is not known exactly how hydroxychloroquine works to treat autoimmune diseases, but researchers believe it may work by interfering with certain communications between the cells in the immune system.3

What are the possible side effects of hydroxychloroquine?

The most common side effects experienced by patients taking hydroxychloroquine include nausea and diarrhea. These side effects usually improve with time. Other side effects that may be experienced with hydroxychloroquine include rash, changes in the pigment of the skin (dark spots or overall darkening), changes to hair, and muscle weakness. In rare cases, hydroxychloroquine may cause anemia, visual changes, or loss of vision.3

Things to know about hydroxychloroquine

Before taking hydroxychloroquine, patients should talk to their doctor about all medications, vitamins, and supplements they are taking. Some medications can interact negatively with other drugs or supplements.

Before starting treatment with hydroxychloroquine, patients should discuss all health conditions with their doctor, especially if they have G6PD deficiency, porphyria, or kidney disease. Women who are pregnant, planning to become pregnant, are breastfeeding, or planning to breastfeed should discuss their condition with their doctor.3

People taking hydroxychloroquine should have regular eye examinations and vision screening tests.3

Dosing information

Hydroxychloroquine is available as a tablet to be taken by mouth, preferably with food to reduce the possibility of side effects like nausea. The dosage is based on the patient’s weight.3 Patients should talk to their doctor about any questions on their dosing regimen.

By providing your email address, you are agreeing to our privacy policy.