Medically Reviewed by Dan Brennan, MD on January 03, 2023
4 min read

Hydroxychloroquine is a prescription drug that’s been around since the 1940s. Doctors first used it to treat malaria.

Today you’re more likely to take it if you have rheumatoid arthritis or lupus. In the early days of the pandemic, you may have heard it could treat COVID-19. 

The World Health Organization (WHO) doesn’t recommend hydroxychloroquine to prevent COVID-19. This suggestion is based on six trials with people who didn’t have the virus. Experts found that hydroxychloroquine had little or no effect on stopping these individuals from infection, hospitalization, or death from COVID-19.

WHO also doesn’t suggest hydroxychloroquine as a COVID-19 treatment. Researchers did 30 trials with over 10,000 cases of COVID-19. Hydroxychloroquine didn’t lower the need for (or time using) ventilators or the risk of death.

The Food and Drug Administration (FDA) pulled its original emergency use approval after a large study found no evidence that the drug could stop deaths or help people with COVID-19 get better faster.

Hydroxychloroquine is most often used to treat autoimmune disorders. That’s when your body’s immune system attacks your cells and tissue by mistake. It can lead to inflammation that damages your joints, muscles, and sometimes your internal organs.

Your doctor might give you hydroxychloroquine if you have:

Experts aren’t sure how hydroxychloroquine helps. They think it’s because the drug changes how your immune cells send signals. It can also turn off certain processes that cause inflammation.

You might not have any problems if you take hydroxychloroquine. But like any drug, it could cause unwanted symptoms. Some are mild and might get better with time.

The most common side effects are:

You could get low blood sugar if your diabetes isn’t under control. It might help if you take hydroxychloroquine with food.

Other symptoms you can get include:

  • Itching or rash
  • Darkening skin or dark spots
  • Hair changes
  • Muscle weakness
  • Mood problems
  • Ringing in your ears

Hydroxychloroquine could cause fatal heart rhythm problems, especially if you take it with another drug. That includes the antibiotic azithromycin. The most common issue is a prolonged QT interval. That’s when your heart’s lower chambers, or ventricles, don’t send electrical signals the right way. It can also make your heart beat too fast. That’s ventricular tachycardia.

It’s rare, but hydroxychloroquine can also damage your eyes. You could have permanent changes in your vision or blindness. You’re more likely to have these kinds of problems if:

  • You’re 60 or older
  • You’ve taken a high dose for more than 5 years
  • You have serious kidney or liver disease
  • You already have an eye or retinal disease

Get regular eye exams if you take this drug long term. Your doctor may want you to get your vision checked every 1-5 years.

Other serious side effects can include:

  • Blood and lymph system disorders
  • Kidney problems
  • Liver injury or failure

Rarely, hydroxychloroquine can cause anemia. That may happen if you have glucose-6-phosphate dehydrogenase (G6PD) deficiency or porphyria. Those are disorders that affect how your red blood cells work.


Hydroxychloroquine doesn’t mix well with certain drugs. It can change the way those medicines work. It can also raise your chances of unwanted side effects. Tell your doctor about any medicine or supplements you’re taking, including vitamins.

Don’t take hydroxychloroquine with:

Drugs it can interact with include:

There’s also a chance it could interact with these drugs:

Talk to your doctor if you take tamoxifen for breast cancer. It might not be safe to take it with hydroxychloroquine for more than 6 months.

It’s safe for most adults and kids to take hydroxychloroquine. Your doctor will use your weight to get the right dose.

Studies show it’s OK to take hydroxychloroquine if you’re pregnant or breastfeeding. Always talk to your doctor about what drugs you’re taking.

Be careful if you have psoriasis. It might make your symptoms worse.

Don’t take hydroxychloroquine if you’re allergic to other drugs with 4-aminoquinoline compounds. That includes medicine such as:

Call 911 or get help right away if you have signs of an allergic reaction. You might get symptoms like:

  • Swelling in your throat, mouth, or face
  • Skin rash or bumps
  • Itching