Side Effects of Plaquenil: What You Need to Know

Plaquenil (hydroxychloroquine) is a prescription drug used for certain types of arthritis, lupus, and malaria. Plaquenil can cause side effects ranging from mild to serious. Examples include hair loss, rash, itching, and eye-related side effects.

Plaquenil is used in adults for:

treating rheumatoid arthritis (RA)
treating systemic lupus erythematosus
treating chronic discoid lupus erythematosus
treating and helping prevent certain forms of malaria

Plaquenil is also used in certain children to treat and help prevent certain forms of malaria.

The active ingredient in Plaquenil is hydroxychloroquine. (An active ingredient is what makes a drug work.) The drug comes as a tablet that you swallow.

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

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Hydroxychloroquine, the active drug in Plaquenil, is not recommended for use in treating COVID-19 (the illness caused by the coronavirus SARS-CoV-2). Do not take any prescription drug, including Plaquenil, unless your doctor recommends that you do so.

For information about how to prepare, advice on prevention and treatment, and expert recommendations, visit our coronavirus hub.

Some people may experience mild or serious side effects during Plaquenil treatment. Examples of Plaquenil’s most commonly reported side effects include:

nausea
vomiting
diarrhea
abdominal pain (sometimes called belly or stomach pain)

Examples of mild side effects that have been reported with Plaquenil include:

hair loss*
changes in hair color
dizziness*
rash and itching*
headache
nausea and vomiting
abdominal pain (sometimes called belly or stomach pain)
diarrhea
fatigue (low energy)
loss of appetite
weight loss

* To learn more about this side effect, see the “Side effects explained” section below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop taking Plaquenil unless your doctor recommends it.

Plaquenil may cause mild side effects other than the ones listed above. See the Plaquenil prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Plaquenil, visit MedWatch.

Serious side effects that have been reported with Plaquenil include:

eye-related side effects*
severe skin-related side effects*
cardiac (heart-related) side effects*
ear-related side effects, such as tinnitus (ringing or buzzing in your ears), spinning sensations, or hearing loss
blood disorders, such as anemia (low red blood cell levels), neutropenia (low white blood cell levels), or thrombocytopenia (low platelet levels)
mental health problems, including mood changes, psychosis, and suicidal thoughts or behavior
liver problems, such as liver failure
low blood sugar level
muscle weakness or wasting
seizures
allergic reaction*†

* To learn more about this side effect, see the “Side effects explained” section below.
† An allergic reaction is possible after taking Plaquenil. But it’s not clear whether this side effect occurred in studies.

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

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

Can Plaquenil cause weight gain?

No, it’s not likely. Weight gain isn’t a known side effect of this drug. In fact, it may have the opposite effect. Loss of appetite and weight loss have been reported in some people taking Plaquenil. But it’s not known how often these side effects occur.

If you’re concerned about Plaquenil and weight gain or weight loss, talk with your doctor. They can suggest ways to help you reach or maintain a body weight that’s healthy for you.

Will I have withdrawal symptoms if I stop taking Plaquenil?

No, you shouldn’t. Withdrawal symptoms are side effects that can happen when you stop taking a drug that your body is dependent on. (With dependence, your body needs the drug to feel like it usually does.) Your body doesn’t become dependent on Plaquenil during treatment. So if you stop taking it, this won’t cause withdrawal symptoms.

If you take Plaquenil for lupus or rheumatoid arthritis, you may notice that stopping treatment makes your condition get worse. That’s because Plaquenil doesn’t cure these conditions, it only reduces their symptoms. So if you stop treatment, this can make your symptoms come back.

But if you take Plaquenil to treat or help prevent malaria, you shouldn’t notice any problems after stopping treatment.

Does my risk of side effects depend on the dose of Plaquenil I take (200 mg, 400 mg, or 600 mg)?

It might. As with many medications, taking high doses of Plaquenil may raise your risk of certain side effects. For example, taking higher doses of Plaquenil could raise your risk of certain eye-related and heart-related side effects. See “Side effects explained” below to read more about these.

Ask your doctor what dosage of Plaquenil is recommended for your condition. They can tell you if this dosage has a higher risk of side effects than other dosages.

Can Plaquenil cause long-term side effects? Will my risk of long-term side effects increase if I take the drug for a long time?

Yes, Plaquenil can cause some long-term side effects. These are side effects that last for a long time or are permanent. Taking Plaquenil for long periods of time can raise your risk of developing certain long-term side effects.

The main long-term side effects of Plaquenil are eye-related. Plaquenil can damage your retina, which may lead to permanent loss of vision. Retinal damage can sometimes continue to get worse even after you stop taking the medication. Taking Plaquenil long term raises your risk of developing retinal damage. To read more about this side effect, see “Side effects explained” below.

Some other serious side effects of Plaquenil, such as certain heart problems, may also last a long time, even with treatment. Exactly how long side effects last will depend on how they respond to any treatments you may have for them. It’s not known if taking Plaquenil long term raises your risk of other side effects.

If you have questions about how long Plaquenil side effects may last, or your risk of long-term side effects, talk with your doctor.

Are there any side effects specific to taking Plaquenil for lupus?

No, there aren’t any side effects that are specific to people taking Plaquenil for lupus. But if you have lupus, you’ll likely need to take Plaquenil long term. And taking Plaquenil long term can raise your risk of certain side effects, such as retinal damage. See the question above to read more about this.

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

Eye-related side effects

It’s not known how often eye-related side effects happen with Plaquenil, but the drug can sometimes cause such side effects.

These include damage to the retina, which is the light-sensitive tissue in the back of your eye. Damage to the retina can cause loss of vision that can be permanent.

Symptoms of retinal damage may include:

decreased vision
trouble seeing in the dark

You may have a raised risk of retinal damage with Plaquenil if you:

take a high Plaquenil dosage
take the medication for longer than 5 years
have a disease affecting your macula (a small area in the center of your retina)
have kidney problems
take certain other medications

Other possible side effects of Plaquenil on eyes include macular degeneration and changes to the cornea, such as swelling or clouding. (The cornea is the front layer of your eye that lets in light.) These side effects can cause changes to your vision, such as blurry vision, double vision, halos around lights, and sensitivity to light. Plaquenil can also cause blind spots in your vision.

What might help

If you have any changes in your vision while taking Plaquenil or after stopping treatment, talk with your doctor right away. They may want you to have an eye exam.

You should have an eye exam within 1 year of starting treatment with Plaquenil. During long-term treatment, you’ll then have more eye exams to check if your vision has changed since starting Plaquenil.

Eye exams are usually recommended every 5 years. But if you have a raised risk of retinal damage, these exams are recommended every year. Eye exams check for any damage to your retina and other problems with your vision.

If you have certain eye side effects, in particular retinal damage, you’ll need to stop taking Plaquenil. And your doctor may switch you to a different treatment for your condition.

If you have retinal damage, your doctor will monitor you closely after you stop treatment. It’s possible the damage may continue, and your vision might continue to get worse.

If you’re concerned about the risk of eye-related side effects with Plaquenil, talk with your doctor.

Hair loss

Some people may have hair loss while taking Plaquenil. But it’s not known how often this side effect occurs.

Hair loss can also be a symptom of lupus and rheumatoid arthritis (RA), which Plaquenil is prescribed to treat.

Note that Plaquenil is occasionally prescribed to treat certain types of hair loss. But it’s not known for sure if it’s effective for this use.

What might help

If you have hair loss while taking Plaquenil, talk with your doctor. They can help work out the cause of your hair loss and suggest ways to help manage it.

If you have hair loss that’s caused by lupus or RA, you may find that Plaquenil lessens this side effect.

If you have arthritis, you may wonder whether taking folic acid can help reduce hair loss with Plaquenil.

Another drug commonly prescribed to treat RA, called methotrexate, often causes side effects such as hair loss. And doctors often prescribe folic acid with methotrexate to help reduce its side effects. Folic acid affects the way methotrexate works. However, taking folic acid with Plaquenil won’t reduce hair loss associated with this medication.

If you’d like to find out more about Plaquenil and hair loss, talk with your doctor.

Dizziness

You might have dizziness while taking Plaquenil. But it’s not known how often this occurs.

It’s possible to have dizziness without any other symptoms. But dizziness can also be a symptom of other side effects of Plaquenil. These include ear-related side effects such as vertigo. With vertigo, you may also have nausea and a sensation of spinning.

Dizziness can also be a symptom of some serious side effects of Plaquenil, such as low blood sugar and heart problems.

What might help

If you have dizzy spells while taking Plaquenil, lie down until the dizziness eases. And be sure to get up slowly.

If you have dizziness that doesn’t ease, or you often have dizzy spells, contact your doctor to get this checked. Your doctor can give further advice on what to do. They may also want to rule out more serious side effects.

Rash, itching, and severe skin-related side effects

It’s not known how often skin-related side effects happen with Plaquenil, but they can occur.

What might help

While taking Plaquenil, it’s important to protect your skin from UV light to avoid getting a sunburn. Don’t use sunlamps and sunbeds, and protect your skin from sunlight with clothing. Use sunscreen on skin that’s not covered.

If you get a sunburn or rash, or experience itching while taking Plaquenil, talk with your doctor. They can recommend ways to manage these side effects. For example, they may suggest using a moisturizer or mild steroid cream, or taking an antihistamine.

However, if you have symptoms of a serious skin-related side effect, contact your doctor right away. If your doctor diagnoses a serious skin reaction from Plaquenil, you’ll need to stop taking the medication.

Cardiac (heart-related) side effects

Plaquenil can sometimes cause heart-related side effects. These include cardiomyopathy (weakening of your heart muscle), heart failure, and irregular heart rhythm. These side effects can be life threatening. It’s not known how often they occur.

You may have a raised risk of heart-related side effects with Plaquenil if you have:

heart disease
a slow or irregular heartbeat
a kind of irregular heart rhythm called a long QT syndrome
low levels of potassium or magnesium in your blood

Taking certain other medications may also increase your risk of these side effects.

Symptoms of heart-related side effects may include:

feeling that your heart is racing, pounding, or skipping beats
fast or irregular heartbeat
feeling dizzy or lightheaded
fainting
fatigue (low energy)
shortness of breath
swollen ankles or feet

What might help

Before prescribing Plaquenil, your doctor will assess if it’s safe for you to take. Talk with your doctor about any heart problems you may have. Also talk with them about any medications you take.

While taking Plaquenil, contact your doctor right away if you have any symptoms of heart-related side effects. But if your symptoms feel life threatening, call 911 or your local emergency number.

If your doctor confirms that you do have heart-related side effects from Plaquenil, you’ll need to stop taking the medication.

Allergic reaction

Like most drugs, Plaquenil can cause an allergic reaction in some people. But it’s not clear whether this side effect occurred in studies.

Symptoms may be mild or serious and can include:

skin rash
itchiness
flushing (temporary warmth, redness, or deepening of skin color)
swelling under your skin, typically in your eyelids, lips, hands, or feet
swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, contact your doctor right away. To manage your symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine). Or they may recommend a product you apply to your skin, such as hydrocortisone cream.

If your doctor confirms you had a mild allergic reaction to Plaquenil, they’ll decide if you should continue taking it.

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 had a serious allergic reaction to Plaquenil, they may have you switch to a different treatment.

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

Plaquenil may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Plaquenil. The list below includes factors to consider.

Allergic reaction. If you’ve had an allergic reaction to Plaquenil or any of its ingredients, you shouldn’t take Plaquenil. In addition, you shouldn’t take Plaquenil if you’ve ever had an allergic reaction to similar drugs, called 4-aminoquinolines. An example is chloroquine. Ask your doctor what other medications are better options for you.

Heart problems. Plaquenil can cause heart-related side effects. If you have a heart problem, ask your doctor if Plaquenil is safe for you. Examples of heart problems include heart disease, such as heart failure, or a past heart attack. They also include heart rate or rhythm problems, such as a slow or irregular heartbeat.

Electrolyte levels. If you have low levels of potassium or magnesium in your blood, you could have a raised risk of certain heart-related side effects with Plaquenil. Your doctor will prescribe medication to increase your potassium or magnesium levels before you start Plaquenil.

Kidney or liver problems. Kidney or liver problems can raise your risk of side effects with Plaquenil. In addition, Plaquenil can also make liver problems worse. If you have kidney or liver problems, your doctor may prescribe a dosage of Plaquenil that’s lower than usual.

Psoriasis or porphyria. Taking Plaquenil could worsen psoriasis or porphyria in some people. If you have either of these conditions, talk with your doctor about whether this medication is right for you.

Blood disorders. Taking Plaquenil could worsen blood disorders, such as anemia (low red blood cell levels), neutropenia (low white blood cell levels), or thrombocytopenia (low platelet levels). If you have a blood disorder, you’ll need frequent blood tests to check your blood cell levels while taking Plaquenil. If Plaquenil makes your condition worse, you’ll need to stop taking it.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD is a protein that helps red blood cells work correctly. In a person who has a deficiency of G6PD, taking Plaquenil could make red blood cells break down. This could lead to low levels of red blood cells. If you have G6PD deficiency, talk with your doctor about whether Plaquenil is safe for you. You may need frequent blood tests while taking this medication.

History of mental health problems. Plaquenil can sometimes cause psychiatric side effects such as psychosis, worsening depression, and suicidal thoughts and actions. If you have a history of depression or other mental health problems, talk with your doctor about whether Plaquenil is right for you.

Diabetes. Plaquenil can sometimes cause low blood sugar. If you’re taking diabetes medication, you may have a raised risk of this side effect. Talk with your doctor about whether you should monitor your blood sugar while taking Plaquenil.

Neurological disorders. Plaquenil can sometimes cause seizures or problems with movement, such as tremors or twitching.If you have a neurological disorder (a condition affecting your brain and nerves), taking Plaquenil could worsen the symptoms of your condition. Talk with your doctor about whether Plaquenil is right for you.

Alcohol and Plaquenil

Drinking alcohol with Plaquenil could raise your risk of certain side effects. These include nausea, diarrhea, dizziness, and liver problems.

If you drink alcohol, talk with your doctor about how much is safe for you to consume while you’re taking Plaquenil.

Pregnancy and breastfeeding while taking Plaquenil

It’s not known for sure if Plaquenil is safe to take during pregnancy. If you’re pregnant or plan to become pregnant, talk with your doctor about the possible risks and benefits of taking Plaquenil.

Small amounts of Plaquenil can pass into breast milk. Side effects haven’t been reported in children who are breastfed by people taking the drug. However, if you’re breastfeeding or plan to breastfeed, talk with your doctor about the best way to feed your child while taking Plaquenil.

Most side effects of Plaquenil are mild and easily managed. However, this medication does have a risk of some serious side effects, so it’s not suitable for everyone.

If you’d like to know more about Plaquenil’s possible side effects and your risk of having problems with this medication, talk with your doctor. They can help you decide if Plaquenil is a good treatment option for you.

Examples of some questions you might want to ask your doctor include:

Am I at a higher risk of side effects with Plaquenil than other people?
Is there anything I can do to reduce my risk of side effects?
Are side effects less common when Plaquenil is taken to help prevent malaria?
Do my other medications raise my risk of side effects with Plaquenil?
Will Plaquenil affect my ability to drive?

To learn more about Plaquenil, see these articles:

All About Plaquenil
All About Plaquenil’s Dosage
Plaquenil Interactions: Alcohol, Medications, and Others

To get information on different conditions and tips for improving your health, subscribe to any of Austra Health’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

Q:

What should I do if Plaquenil upsets my stomach?

A:

Stomach-related side effects, such as nausea, vomiting, diarrhea, and belly pain, are common with Plaquenil. To reduce your risk of these side effects, it’s recommended that you take Plaquenil with food or milk.

If you experience nausea or vomiting while taking Plaquenil, try eating smaller meals or plain foods, or drinking cold liquids. For diarrhea, it may help to eat foods that are low in fiber and bland, such as bananas or white rice. See this article for other at-home remedies you can try to ease your upset stomach.

Over-the-counter (OTC) medications may also help decrease these symptoms. For example, if you have diarrhea, you can try taking loperamide (Imodium).

You may also use bismuth subsalicylate (Kaopectate, Pepto-Bismol) to treat nausea, vomiting, and diarrhea. But be sure to talk with your doctor first about how much to take. High doses of bismuth subsalicylate with Plaquenil can increase your risk of low blood sugar.

Other OTC medications that can help relieve an upset stomach include antacids and kaolin (a type of clay used in some medications), but these can reduce how well Plaquenil works. To avoid this, make sure to take antacids or kaolin-containing products at least 4 hours before or after you take Plaquenil.

You should avoid taking cimetidine (Tagamet) with Plaquenil because it can increase the level of Plaquenil in your body. This may increase your risk of side effects.

For more information on how to treat or help prevent an upset stomach, talk with your doctor or pharmacist. And be sure to ask whether any OTC medications you might want to use are safe to take with Plaquenil.

The Austra Health Pharmacist Team Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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Disclaimer: Austra Health 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.

Last medically reviewed on April 8, 2023

How we reviewed this article:

Austra Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Chloroquine or hydroxychloroquine and/or azithromycin. (2021).
covid19treatmentguidelines.nih.gov/therapies/antiviral-therapy/chloroquine-or-hydroxychloroquine-and-or-azithromycin/
Hydroxychloroquine. (2023).
ncbi.nlm.nih.gov/books/NBK501150/
Plaquenil (hydroxychloroquine sulfate) tablets, for oral use. (2022).
accessdata.fda.gov/drugsatfda_docs/label/2022/009768s056lbl.pdf

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