Plaquenil Side Effects Center

Last updated on RxList: 7/25/2022
Plaquenil Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Plaquenil?

Plaquenil (hydroxychloroquine) is an antimalarial medication used to treat or prevent malaria, a disease caused by parasites, which enter the body through the bite of a mosquito. Plaquenil is also used to treat symptoms of rheumatoid arthritis and discoid or systemic lupus erythematosus. Plaquenil is available in generic form.

What Are Side Effects of Plaquenil?

Common side effects of Plaquenil include

  • nausea,
  • vomiting,
  • stomach pain or cramps,
  • loss of appetite,
  • weight loss,
  • diarrhea,
  • dizziness,
  • spinning sensation,
  • headache,
  • ringing in your ears,
  • mood changes,
  • nervousness,
  • irritability,
  • skin rash,
  • itching, or
  • hair loss.

Tell your doctor if you experience serious side effects of Plaquenil including

  • muscle weakness,
  • twitching,
  • uncontrolled movement,
  • loss of balance or coordination,
  • blurred vision,
  • light sensitivity,
  • seeing halos around lights,
  • pale skin,
  • easy bruising or
  • bleeding,
  • confusion,
  • unusual thoughts or behavior, or
  • seizures (convulsions).

Plaquenil may cause serious side effects including:

  • trouble focusing your eyes,
  • light flashes in your vision,
  • swelling or color changes in your eyes,
  • headache with chest pain and severe dizziness,
  • fainting,
  • fast or pounding heartbeats,
  • very slow heart rate,
  • weak pulse,
  • muscle weakness,
  • numbness or tingling,
  • headache,
  • hunger,
  • sweating,
  • irritability,
  • dizziness,
  • nausea,
  • fast heart rate,
  • feeling anxious or shaky,
  • fever,
  • chills,
  • sore throat,
  • weakness or ill feeling,
  • swollen gums,
  • mouth sores,
  • skin sores,
  • pale skin,
  • easy bruising,
  • unusual bleeding, and
  • feeling lightheaded

Get medical help right away, if you have any of the symptoms listed above.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheartedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Plaquenil

The adult dose of Plaquenil to suppress malaria is 400 mg on the same day each week. The pediatric weekly suppressive dosage is 5 mg/kg of body weight. The adult dose of Plaquenil to treat an acute attack of malaria is an initial dose of 800 mg followed by 400 mg in six to eight hours and 400 mg for two more days. To treat lupus erythematosus, the average adult dose is 400 mg once or twice daily.

What Drugs, Substances, or Supplements Interact with Plaquenil?

Plaquenil may interact with acetaminophen, cancer medications, tuberculosis medications, birth control pills or hormone replacement therapy, arthritis medications, ACE inhibitors, antibiotics, antifungals, cholesterol medications, HIV/AIDS medications, NSAIDs (non-steroidal anti-inflammatory drugs), or seizure medications. Tell your doctor all medications you use.

Plaquenil During Pregnancy and Breastfeeding

Plaquenil should be used only when prescribed during pregnancy. This medication is not recommended to treat rheumatoid arthritis during pregnancy. This medication passes into breast milk. Consult your doctor before breast-feeding.

Additional Information

Our Plaquenil (hydroxychloroquine) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Plaquenil Consumer Information

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Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Also seek emergency medical attention if you have symptoms of a serious heart problem: fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out).

Call your doctor at once if you have:

  • a seizure;
  • yellowing of your eyes;
  • ringing in your ears, trouble hearing;
  • unusual mood changes;
  • severe muscle weakness, loss of coordination, underactive reflexes;
  • low blood cell counts--fever, chills, tiredness, sore throat, mouth sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;
  • low blood sugar--headache, hunger, sweating, irritability, dizziness, fast heart rate, and feeling anxious or shaky; or
  • a serious drug reaction that can affect many parts of your body--skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

Taking hydroxychloroquine long-term or at high doses may cause irreversible damage to the retina of your eye. Stop taking hydroxychloroquine and tell your doctor if you have:

  • blurred vision, trouble focusing, trouble reading;
  • distorted vision, blind spots;
  • changes in your color vision;
  • hazy or cloudy vision;
  • seeing light flashes or streaks, seeing halos around lights; or
  • increased sensitivity to light.

Common side effects may include:

  • headache, dizziness;
  • nausea, vomiting, stomach pain;
  • loss of appetite, weight loss;
  • feeling nervous or irritable;
  • skin rash or itching; or
  • hair loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Plaquenil Professional Information


The following adverse reactions are described in greater detail in other sections:

The following adverse reactions have been identified during post-approval use of 4- aminoquinoline drugs, including PLAQUENIL. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:


Drugs Prolonging QT Interval And Other Arrhythmogenic Drugs

PLAQUENIL prolongs the QT interval. There may be an increased risk of inducing ventricular arrhythmias if PLAQUENIL is used concomitantly with other arrhythmogenic drugs. Therefore, PLAQUENIL is not recommended in patients taking other drugs that have the potential to prolong the QT interval or are arrhythmogenic [see WARNINGS AND PRECAUTIONS].

Insulin Or Other Antidiabetic Drugs

PLAQUENIL may enhance the effects of insulin and antidiabetic drugs, and consequently increase the hypoglycemic risk. Therefore, a decrease in dosage of insulin and other antidiabetic drugs may be necessary [see WARNINGS AND PRECAUTIONS].

Drugs That Lower The Seizure Threshold

PLAQUENIL can lower the seizure threshold. Co-administration of PLAQUENIL with other antimalarials known to lower the seizure threshold (e.g., mefloquine) may increase the risk of seizures.


The activity of antiepileptic drugs might be impaired if co-administered with PLAQUENIL.


Concomitant use of PLAQUENIL and methotrexate may increase the incidence of adverse reactions.


An increased plasma cyclosporin level was reported when cyclosporin and PLAQUENIL were co-administered. Monitor serum cyclosporine levels closely in patients receiving combined therapy.


Concomitant PLAQUENIL and digoxin therapy may result in increased serum digoxin levels. Monitor serum digoxin levels closely in patients receiving combined therapy.


Concomitant use of cimetidine resulted in a 2-fold increase of exposure of chloroquine, which is structurally related to hydroxychloroquine. Interaction of cimetidine with hydroxychloroquine cannot be ruled out. Avoid concomitant use of cimetidine.


Lack of efficacy of hydroxychloroquine was reported when rifampicin was concomitantly administered. Avoid concomitant use of rifampicin.


Chloroquine has been reported to reduce the bioavailability of praziquantel. Interaction of praziquantel with hydroxychloroquine cannot be ruled out.

Antacids And kaolin

Antacids and kaolin can reduce absorption of chloroquine; an interval of at least 4 hours between intake of these agents and chloroquine should be observed. Interaction of antacids and kaolin with hydroxychloroquine cannot be ruled out.


In a study of healthy volunteers, chloroquine significantly reduced the bioavailability of ampicillin. Interaction of ampicillin with hydroxychloroquine cannot be ruled out.

Read the entire FDA prescribing information for Plaquenil (Hydroxychloroquine)


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© Plaquenil Patient Information is supplied by Cerner Multum, Inc. and Plaquenil Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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