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Plaquenil Side Effects

Generic Name: hydroxychloroquine

Note: This page contains side effects data for the generic drug hydroxychloroquine. It is possible that some of the dosage forms included below may not apply to the brand name Plaquenil.

For the Consumer

Applies to hydroxychloroquine: oral tablet

As well as its needed effects, hydroxychloroquine (the active ingredient contained in Plaquenil) may cause unwanted side effects that require medical attention. When this medicine is used for short periods of time, side effects usually are rare. However, when it is used for a long time and/or in high doses, side effects are more likely to occur and may be serious.

Major Side Effects

If any of the following side effects occur while taking hydroxychloroquine, check with your doctor immediately:

Less common:
  • Blurred vision or any other change in vision—this side effect may also occur or get worse after you Stop taking hydroxychloroquine
  • Convulsions (seizures)
  • increased muscle weakness
  • mood or other mental changes
  • ringing or buzzing in ears or any loss of hearing
  • sore throat and fever
  • unusual bleeding or bruising
  • unusual tiredness
  • weakness
Symptoms of overdose:
  • Drowsiness
  • headache
  • increased excitability

Minor Side Effects

Some hydroxychloroquine side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common:
  • Diarrhea
  • difficulty in seeing to read
  • headache
  • itching (more common in black patients)
  • loss of appetite
  • nausea or vomiting
  • stomach cramps or pain
Less common:
  • Bleaching of hair or increased hair loss
  • blue-black discoloration of skin, fingernails, or inside of mouth
  • dizziness or lightheadedness
  • nervousness or restlessness
  • skin rash

For Healthcare Professionals

Applies to hydroxychloroquine: compounding powder, oral tablet


In general, although not every side effect listed in the side effects section may have been reported with the use of hydroxychloroquine (the active ingredient contained in Plaquenil) they have all been reported with the use of one or more 4-aminoquinoline compounds.[Ref]


Ocular side effects have included disturbances of accommodation with symptoms of blurred vision (dose-related and reversible with treatment cessation). Corneal side effects have included transient edema, punctate to lineal opacities, decreased corneal sensitivity, corneal changes (with or without accompanying symptoms, including blurred vision, halos around lights, photophobia), and corneal deposits. Retinal (macular) side effects have included edema, atrophy, abnormal pigmentation (mild pigment stippling to a "bullseye" appearance), loss of foveal reflex, increased macular recovery time following exposure to a bright light (photostress test), and elevated retinal threshold to red light in macular, paramacular, and peripheral retinal areas. Other fundus changes have included optic disc pallor and atrophy, attenuation of retinal arterioles, fine granular pigmentary disturbances in the peripheral retina, and prominent choroidal patterns in advanced stage. Visual field defects have included pericentral or paracentral scotoma, central scotoma with decreased visual acuity, rarely field constriction, and abnormal color vision. The most common visual symptoms attributed to retinopathy are reading and vision difficulties (words, letters, or parts of objects missing), photophobia, blurred distance vision, missing or blacked out areas in the central or peripheral visual field, and light flashes and streaks. Patients with retinal changes may have visual symptoms or may be asymptomatic (with or without visual field changes). Rarely scotomatous vision or field defects may occur without obvious retinal change. A few cases of retinal changes consisting of change in retinal pigmentation (detected on periodic ophthalmologic examination) with visual field defects in some instances have been reported in patients receiving only hydroxychloroquine (the active ingredient contained in Plaquenil) A case of delayed retinopathy with vision loss starting 1 year after hydroxychloroquine discontinuation has been reported. Night vision difficulties and immediate blurred vision have been reversible with treatment cessation.[Ref]

The corneal changes (fairly common) have been reversible. Corneal deposits have been reported as early as 3 weeks after the initiation of therapy.

Retinopathy appears to be dose related and has occurred within several months (rarely) to several years of daily therapy.[Ref]


Gastrointestinal side effects have included diarrhea, anorexia, nausea, abdominal cramps, vomiting, and epigastric pain. A case of pigmentation of the gums has also been reported.[Ref]

Nervous system

Nervous system side effects have included headache, dizziness, vertigo, tinnitus, nystagmus, nerve deafness, convulsions, and ataxia.[Ref]


Psychiatric side effects have included irritability, nervousness, emotional changes, nightmares, and psychosis.[Ref]


Musculoskeletal side effects have included skeletal muscle palsies, skeletal muscle myopathy, or neuromyopathy leading to progressive weakness and atrophy of proximal muscle groups which may be associated with mild sensory changes, depression of tendon reflexes, and abnormal nerve conduction. Absent or hypoactive deep tendon reflexes and extraocular muscle palsies have been reported. Neuromyotoxicity has been associated with hydroxychloroquine (the active ingredient contained in Plaquenil) concurrently with worsening renal function.[Ref]


Mucocutaneous hyperpigmentation over all extremities, the torso, and the hairline has been reported in an elderly man after long-term hydroxychloroquine (the active ingredient contained in Plaquenil) use. Skin biopsies demonstrated sharply defined red-brown fibers in the deep dermis and the classic "banana-shaped body" associated with exogenous ochronosis.[Ref]

Dermatologic side effects have included nonlight-sensitive psoriasis, bleaching of hair, alopecia, pruritus, skin and mucosal pigmentation, photosensitivity, and skin eruptions (urticarial, morbilliform, lichenoid, maculopapular, purpuric, erythema annulare centrifugum, Stevens-Johnson syndrome, acute generalized exanthematous pustulosis, and exfoliative dermatitis). A case of generalized pustular drug rash has also been reported.[Ref]


Hematologic side effects have included various blood dyscrasias such as aplastic anemia, agranulocytosis, leukopenia, anemia, and thrombocytopenia. Hemolysis has been reported in individuals with glucose-6-phosphate dehydrogenase deficiency.[Ref]


The causal relationship of hydroxychloroquine (the active ingredient contained in Plaquenil) to cardiomyopathy has not been established.[Ref]

Cardiovascular side effects have rarely included cardiomyopathy with high daily dosages.[Ref]


Hepatic side effects have included isolated cases of abnormal liver function and fulminant hepatic failure.[Ref]


Metabolic side effects have included weight loss and exacerbation or precipitation of porphyria.


Other side effects have included lassitude.[Ref]


Hypersensitivity side effects have included allergic reactions (urticaria, angioedema, and bronchospasm) and hypersensitivity myocarditis.[Ref]


Endocrine side effects have included a case report of hypoglycemia induced by hydroxychloroquine (the active ingredient contained in Plaquenil) in a type II diabetic treated for polyarthritis.[Ref]


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15. Meller S, Gerber PA, Homey B "Clinical image: blonde by prescription." Arthritis Rheum 58 (2008): 2286

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18. Manohar VA, Moder KG, Edwards WD, Klarich K "Restrictive cardiomyopathy secondary to hydroxychloroquine therapy." J Rheumatol 36 (2009): 440-1

19. Abbasi S, Tarter L, Farzaneh-Far R, Farzaneh-Far A "Hydroxychloroquine: a treatable cause of cardiomyopathy." J Am Coll Cardiol 60 (2012): 786

20. Makin AJ, Wendon J, Fitt S, Portmann BC, Williams R "Fulminant hepatic failure secondary to hydroxychloroquine." Gut 35 (1994): 569-70

21. Kounis GN, Kouni SA, Chiladakis JA, Kounis NG "Comment: Mesalamine-Associated Hypersensitivity Myocarditis in Ulcerative Colitis and the Kounis Syndrome (February)." Ann Pharmacother 43 (2009): 393-4

22. Evans CC, Bergstresser PR "Acute generalized exanthematous pustulosis precipitated by hydroxychloroquine." J Am Acad Dermatol 50 (2004): 650-1

23. Shojania K, Koehler BE, Elliott T "Hypoglycemia induced by hydroxychloroquine in a type II diabetic treated for polyarthritis." J Rheumatol 26 (1999): 195-6

It is possible that some side effects of Plaquenil may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.