Key takeaways
- Plaquenil (hydroxychloroquine) is prescribed for rheumatoid arthritis, lupus, and malaria.
- Common side effects include nausea, vomiting, diarrhea, and abdominal pain.
- Serious side effects can include retinal damage (which may be permanent), skin reactions, heart problems, blood disorders, and liver problems.
Like most drugs, Plaquenil can cause side effects that range from mild to serious. Learn more about these side effects, including which ones are more common, and tips for managing them.
Plaquenil can cause certain side effects, some of which are more common than others. These are just a few of the more common side effects reported by people who took Plaquenil in clinical studies:
Quick note: These lists may not include all possible side effects of Plaquenil. To learn more, talk with your doctor or pharmacist or refer to the drug’s prescribing information.
Other than the more common side effects, other mild side effects that have been reported with Plaquenil include:
- dizziness
- fatigue
- nervousness or irritability
- hair loss
- headache
- weight loss
- mild allergic reaction
These side effects may be temporary, lasting a few days or weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.
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Experiencing side effects? After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews its side effects. If you develop a side effect while taking this medication and want to report it to the FDA, you can visit MedWatch or call 800-FDA-1088.
Serious side effects that have been reported with Plaquenil include:
- ear or hearing problems, including deafness or tinnitus (ringing in your ears)
- blood disorders, including low levels of white blood cells, red blood cells, or platelets
- liver problems, including liver failure
- hypoglycemia (low blood sugar)
- muscle or nerve problems
- sleep problems, including nightmares
- suicidal thoughts or behaviors
- ocular (eye) problems (see “Managing side effects”)
- skin reactions (see “Managing side effects”)
- cardiac (heart) problems (see “Managing side effects”)
- serious allergic reaction
If you develop serious side effects while taking Plaquenil, 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.
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 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.
No, weight gain hasn’t been reported as a side effect of Plaquenil. But weight loss has been reported as a side effect.
However, two conditions Plaquenil is prescribed to treat, rheumatoid arthritis (RA) and lupus, can cause symptoms that contribute to weight gain.
No, you shouldn’t expect withdrawal symptoms or similar side effects when you stop taking Plaquenil. (Withdrawal symptoms are uncomfortable effects that occur when you stop taking a drug or substance that your body is used to.)
Be sure to talk with your doctor before stopping Plaquenil.
Most of Plaquenil’s side effects are temporary and last for a few days or weeks. But some side effects could be long term.
For example, tinnitus (ringing in your ears) or hearing loss caused by Plaquenil may not go away. Plaquenil can also damage your retina (a layer of light-sensitive cells in the back of the eye that helps you see clearly). Retinal damage can be permanent.
The drug can also cause heart failure, which is a chronic (long-term) condition.
No, people taking Plaquenil in clinical studies didn’t report any side effects related to teeth.
However, RA and lupus, two conditions that Plaquenil treats, can cause problems related to teeth and oral health. Recent studies have found connections between both RA and lupus and being at increased risk for problems with dental health. This includes an increased risk of periodontal (gum) disease.
Learn more about some of the side effects Plaquenil may cause, as well as tips for managing them.
Ocular (eye) problems
Plaquenil can cause ocular (eye-related) problems. This can include damage to your retina (a layer of light-sensitive cells in the back of the eye that helps you see clearly).
Retinal damage caused by Plaquenil can be permanent. Sometimes, this damage can continue to worsen even after you stop taking the drug.
What you can do
Before you begin taking Plaquenil, tell your doctor about your complete medical history and all medications you take. Your doctor will use this information to determine your risk for retinal damage if you take Plaquenil.
Because of the risk of eye-related side effects, you should have an eye exam within 1 year of starting Plaquenil. Then, depending on your risk for eye problems, your doctor may recommend that you have annual eye exams while taking Plaquenil. If you’re at low risk, you may not need another eye exam unless you take the drug for at least 5 years.
Skin reactions
It’s possible for Plaquenil to cause skin reactions, such as:
- Stevens-Johnson syndrome
- toxic epidermal necrolysis
- a reaction that causes eosinophilia and systemic (total body) symptoms
- acute generalized exanthematous pustulosis (sudden widespread rash that may occur with swelling and fever)
Although rare, these reactions are very serious and require hospital treatment. In extreme cases, they can be life threatening.
Cardiac (heart) problems
Taking Plaquenil can cause cardiac (heart-related) problems. These include:
- cardiomyopathy (a disease of your heart muscle that makes it harder for the heart to pump blood to the rest of your body)
- heart failure
- irregular heart rhythm, including long QT syndrome
Although rare, some of these problems can be life threatening.
What you can do
Before you start Plaquenil, tell your doctor about your medical history and all of the medications you take. You shouldn’t take Plaquenil with certain drugs that can affect your heart rhythm. (See this article for details and examples of these drugs.)
Your doctor will determine your risk for heart-related problems with Plaquenil. And they’ll monitor your heart health during treatment. If you develop any heart-related side effects, they’ll probably have you stop taking Plaquenil.
Diarrhea
Taking Plaquenil can cause diarrhea. This side effect was commonly reported in clinical studies.
Tips for managing this side effect include:
- Staying hydrated.
- Eating a bland diet.
- Taking over-the-counter medications, such as loperamide (Imodium)
If you have diarrhea that won’t go away, is severe, or bothers you, contact your doctor. They may be able to recommend a treatment for this side effect. If it won’t go away, they may recommend switching treatments.
What can you do today?Have you noticed patterns in when side effects tend to feel more noticeable? Consider using this checklist as a simple way to track them.
- Note what you feel and when it started (how long after your dose).
- Rate it on a scale of 1-5 and note how long it lasts.
- Check if it’s new for you or getting worse.
- Record the other things you may have taken today, such as over-the-counter supplements, prescription medications, alcohol, or energy drinks.
Quick tip: You can screenshot this checklist or copy it into your notes app to have for a future reference.
Be sure to talk with your doctor about your health history before you take Plaquenil. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:
- blood disorders, such as anemia (low red blood cell levels)
- low magnesium or potassium
- porphyria
- neurological disorder (a condition that affects your brain and nerves)
- gastrointestinal (GI) conditions
- glucose-6-phosphate dehydrogenase (G6PD) deficiency
- history of suicidal thoughts or behaviors or mental health problems
- kidney disease
- liver disease, including hepatitis
- psoriasis
- if you’ve ever had an allergic reaction to Plaquenil or any of its ingredients
- pregnancy
- breastfeeding
Plaquenil can cause mild or serious side effects. Your doctor or pharmacist can help answer any questions you have about side effects you experience during your treatment.
Disclaimer: While Medical News Today strives for factual, comprehensive, and current drug information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses. Learn more about our approach to content integrity.