Hydroxychloroquine is a generic prescription drug for malaria and other conditions. It’s also available as the brand-name drugs Plaquenil and Sovuna. Hydroxychloroquine can cause mild to serious side effects, including eye, heart, and liver problems.

Hydroxychloroquine is used to:

Hydroxychloroquine comes as a tablet that you swallow.

Keep reading to learn about the common, mild, and serious side effects that hydroxychloroquine can cause. For a general overview of the drug, including details about its uses, see this article.

Note: Hydroxychloroquine was approved by the Food and Drug Administration (FDA) in 1955. At that time, researchers were not required to collect specific details about side effects. Detailed information on hydroxychloroquine’s side effects was not collected until after the drug became available for public use. It isn’t known for certain whether the side effects listed in this article occurred in the drug’s studies.

Some people may experience mild to serious side effects during their hydroxychloroquine treatment. Examples of the drug’s commonly reported side effects include:

  • abdominal pain
  • diarrhea
  • nausea and vomiting

Mild side effects have been reported with hydroxychloroquine. These include:

  • abdominal pain
  • changes in hair color
  • diarrhea
  • dizziness
  • fatigue (low energy)
  • feeling irritable or nervous
  • hair loss
  • headache
  • loss of appetite
  • nausea and vomiting
  • skin itching or rash
  • weight loss

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop taking hydroxychloroquine unless your doctor recommends it.

Hydroxychloroquine may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Serious side effects have been reported with hydroxychloroquine. These include:

If you develop serious side effects while taking hydroxychloroquine, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Hydroxychloroquine’s side effects explained” section.

Note: After the FDA approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with hydroxychloroquine, visit MedWatch.

ALLERGIC REACTION

For some people, hydroxychloroquine can cause an allergic reaction. But it’s not clear whether this side effect occurred in the drug’s studies.

In general, symptoms of allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should keep taking hydroxychloroquine.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to hydroxychloroquine, they may have you switch to a different treatment.

Get answers to some frequently asked questions about hydroxychloroquine’s side effects.

Does hydroxychloroquine cause long-term side effects?

It’s possible. Long-term side effects include those that may not go away, even after you stop taking the drug. It also includes side effects that may start at any time you’re taking a drug, even if you’ve taken it for a long time.

Examples of long-term side effects reported with hydroxychloroquine include:

For details about eye and heart problems, see the “Hydroxychloroquine’s side effects explained” section.

Talk with your doctor to learn more about the possible side effects of hydroxychloroquine and how long they may last.

Can hydroxychloroquine cause weight gain?

It’s not likely. Weight gain wasn’t reported as a side effect of hydroxychloroquine.

Instead, loss of appetite and weight loss have been reported with the drug. But it isn’t known how common these side effects are or what amount of weight loss may result.

If you notice weight changes while you’re taking hydroxychloroquine, talk with your doctor. They can help determine what may be causing it. Your doctor can also recommend ways to maintain a weight that’s healthy for you.

Learn more about some of the side effects hydroxychloroquine may cause.

Eye problems

Eye problems are possible with hydroxychloroquine. But it isn’t known how often these side effects were reported in the drug’s studies.

Eye problems may include damage to the retina, which is the layer of tissue that lines the back of your eye. Retina damage may lead to permanent vision loss. Symptoms of this side effect can include eye floaters and difficulty seeing at night.

Certain factors can increase the risk of retina damage when taking hydroxychloroquine. These include:

  • take the drug for more than 5 years
  • taking high doses of the drug
  • having kidney problems
  • having a condition that affects your macula (the center of your retina)
  • taking other medications that may cause retina damage

Other eye problems are also possible with hydroxychloroquine. A few examples include nystagmus (uncontrollable eye movements), cloudy vision, and swelling of the cornea. (The cornea is the surface that covers the front of your eye.)

What might help

Your doctor will likely recommend getting an eye exam before you start taking hydroxychloroquine. They may also recommend getting regular eye exams during treatment.

If you have eye problems during hydroxychloroquine treatment, talk with your doctor. They’ll tell you whether it’s safe to keep taking the drug. If needed, they’ll recommend alternatives to hydroxychloroquine.

Heart problems

Heart problems are possible with hydroxychloroquine. However, it isn’t known how common these side effects were in the drug’s studies.

Heart problems may include cardiomyopathy (weakened heart muscle), irregular heart rhythm, and heart failure. In severe cases, heart problems with hydroxychloroquine may be life threatening.

Heart problems may cause symptoms such as fatigue (low energy), chest pain, and heart palpitations. Other symptoms may include shortness of breath and swelling due to water retention.

Certain factors can increase the risk of heart problems when taking hydroxychloroquine. These include:

  • having heart disease, such as heart failure
  • having an irregular heart rhythm or a related condition, such as long QT syndrome and slow heart rate
  • having low blood levels of potassium or magnesium
  • taking other medications that may affect heart rhythm

What might help

If you have symptoms of a heart problem during hydroxychloroquine treatment, contact your doctor. But if your symptoms seem severe or life threatening, call 911 or your local emergency number.

If you have a heart problem, your doctor will tell you whether it’s safe to keep taking hydroxychloroquine. If needed, they’ll recommend alternative treatments.

Liver problems

Liver problems are possible with hydroxychloroquine. But it isn’t known how often these side effects were reported in the drug’s studies.

Liver problems may include changes in liver function tests and liver failure. Symptoms may include:

  • jaundice (yellowing of the skin or eyes)
  • abdominal pain
  • loss of appetite
  • nausea or vomiting

What might help

If you have symptoms of a liver problem during hydroxychloroquine treatment, talk with your doctor. They may give you blood tests to check your liver function.

If you have a liver problem, your doctor will tell you whether it’s safe to keep taking the drug. If needed, they’ll recommend alternatives to hydroxychloroquine.

Keeping track of side effects

During your hydroxychloroquine treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start a new drug or combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Sharing notes with your doctor will help them learn more about how hydroxychloroquine affects you. They can then use this information to adjust your treatment plan if needed.

Below is important information you should consider before starting treatment with hydroxychloroquine.

Warnings

Hydroxychloroquine can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether hydroxychloroquine is a good treatment option for you.

Talk with your doctor about your health history before you take hydroxychloroquine. Be sure to tell them if any of the following factors apply to you:

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

  • Call or text the 988 Suicide and Crisis Lifeline at 988 or chat at 988lifeline.org. Caring counselors are available to listen and provide free and confidential support 24/7.
  • Text HOME to the Crisis Text Line at 741741 to connect with a volunteer crisis counselor for free and confidential support 24/7.
  • Not in the United States? Find a helpline in your country with Befrienders Worldwide.
  • Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you’re not in the same household, stay on the phone with them until help arrives.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.