Hydroxychloroquine is an anti-inflammatory and immunomodulatory drug that helps treat autoimmune and rheumatic diseases, such as ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic joint disease that primarily affects the spine, sacroiliac joints, and surrounding soft tissue, such as ligaments and tendons.

It usually develops in people under the age of 40 years. In around 80% of cases, symptoms develop before someone reaches 30 years of age.

In this article, we will take a closer look at hydroxychloroquine and what older research says about its use for AS.

A person holding a bottle of hydroxychloroquine and one of the pillsShare on Pinterest
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Hydroxychloroquine (Plaquenil) is an anti-inflammatory and immunomodulatory drug.

Doctors prescribe it to manage autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis (RA).

It helps treat autoimmune diseases by reducing inflammation and increasing the body’s immune response.

The drug is relatively safe to use in high doses over long periods, making it suitable for managing chronic conditions.

Learn more about hydroxychloroquine.

There is not much research on whether hydroxychloroquine is an effective treatment for AS.

However, evidence shows that the drug is effective in treating RA, a similar inflammatory condition.

Health experts do not fully know how hydroxychloroquine works to treat RA. However, they know that the drug prevents lysosomes from releasing inflammatory enzymes and cytokines, which affect the immune system.

Like RA, ankylosing spondylitis involves chronic inflammation. Cytokines play an important role in producing symptoms such as inflammation and fibrosis. This suggests that hydroxychloroquine may have similar effects on AS.

The typical hydroxychloroquine dosage is 400 milligrams (mg) daily, either in one or two doses. It is usually available in 200-mg tablets.

A doctor will advise a person on the specific dose.

Hydroxychloroquine takes effect gradually. It can take between 6 and 12 weeks before people experience an improvement in symptoms.

Common side effects of hydroxychloroquine include:

  • headache
  • dizziness
  • gastrointestinal distress
  • rash

Rarely, the drug can also cause the following:

  • hair loss
  • skin hyperpigmentation
  • agranulocytosis, which makes people vulnerable to infection
  • aplastic anemia, a condition that damages stem cells in a person’s bone marrow
  • leukopenia, which is a low number of white blood cells
  • low platelet count
  • vertigo
  • transaminitis, which refers to atypically high levels of a family of enzymes called transaminases

Another uncommon but serious side effect is retinopathy, which can lead to vision loss. People taking the drug long term should get regular eye exams.

People with existing heart conditions and a higher risk of retinopathy may need to take additional precautions when taking hydroxychloroquine.

They can discuss with a doctor whether the drug is a suitable option for them and whether the risks outweigh the benefits.

People should always speak with a doctor when considering a new treatment plan and let them know of any existing conditions, such as heart or vision issues.

Research is ongoing into hydroxychloroquine as a treatment for inflammatory conditions such as AS. The exact mechanism of the drug remains unclear.

While doctors consider it an effective treatment for RA, there is little research into the efficacy of hydroxychloroquine for AS.

Research suggests the drug is relatively safe when a person takes it over a long period to treat rheumatic diseases. This indicates that hydroxychloroquine could be an effective tool for managing AS.