Skip to Content

Chloroquine Side Effects

For the Consumer

Applies to chloroquine: oral tablet

Side effects requiring immediate medical attention

Along with its needed effects, chloroquine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking chloroquine:

Incidence not known

  • Anxiety
  • attempts at killing oneself
  • back, leg, or stomach pains
  • black, tarry stools
  • bleeding gums
  • blistering, peeling, or loosening of the skin
  • blood in the urine or stools
  • blurred or decreased vision
  • change in near or distance vision
  • chest discomfort or pain
  • chills
  • cold sweats
  • confusion
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cough
  • dark urine
  • diarrhea
  • difficulty in focusing the eyes
  • difficulty with speaking
  • difficulty with swallowing
  • disturbed color perception
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • double vision
  • drooling
  • fast, slow, irregular, or pounding heartbeat
  • feeling that others are watching you or controlling your behavior
  • feeling that others can hear your thoughts
  • feeling, seeing, or hearing things that are not there
  • fever
  • general tiredness and weakness
  • halos around lights
  • headache
  • hearing loss
  • inability to move the eyes
  • increased blinking or spasms of the eyelid
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • loss of balance control
  • lower back or side pain
  • muscle trembling, jerking, or stiffness
  • muscular pain, tenderness, wasting, or weakness
  • night blindness
  • nausea
  • overbright appearance of lights
  • painful or difficult urination
  • pale skin
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • restlessness
  • shuffling walk
  • skin rash, hives, or itching
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sticking out of the tongue
  • stiffness of the limbs
  • sweating
  • swollen or painful glands
  • tightness in the chest
  • trouble breathing
  • tunnel vision
  • twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
  • uncontrolled movements, especially of the face, neck, and back
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • upper right abdominal or stomach pain
  • vomiting
  • yellow eyes and skin

Get emergency help immediately if any of the following symptoms of overdose occur while taking chloroquine:

Symptoms of overdose

  • Cold, clammy skin
  • decreased urine
  • drowsiness
  • dry mouth
  • fast, weak pulse
  • increased thirst
  • lightheadedness, dizziness, or fainting
  • loss of appetite
  • muscle pain or cramps
  • numbness or tingling in the hands, feet, or lips

Side effects not requiring immediate medical attention

Some side effects of chloroquine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

  • Change in hair color
  • hair loss
  • increased sensitivity of the skin to sunlight
  • redness or other discoloration of the skin
  • severe sunburn
  • stomach cramps
  • trouble sleeping
  • weight loss

For Healthcare Professionals

Applies to chloroquine: compounding powder, injectable solution, oral tablet


Maculopathy and macular degeneration may be irreversible.

Irreversible retinal damage has been reported in patients receiving long-term or high-dose 4-aminoquinoline therapy. Retinopathy has been reported as dose related.[Ref]

Frequency not reported: Maculopathy; macular degeneration; irreversible retinal damage; retinopathy; double vision; visual disturbances (blurred vision, focusing or accommodation difficulty); decreased visual acuity; color-vision defects; nyctalopia; scotomatous vision with field defects of paracentral, pericentral ring types, and typically temporal scotomas, (e.g., difficulty in reading with words tending to disappear, seeing half an object, misty vision, fog before the eyes); pigmentary retinopathy; corneal deposits; keratopathy; decreased corneal sensitivity; corneal edema; reversible corneal opacities[Ref]


Pruritus has been seen more commonly in Africans. The onset was generally 6 to 48 hours after the first dose and antihistamines may or may not control the pruritus.

Increased pigmentation of the skin and mucous membranes was generally of a bluish color; may not be reversible on discontinuation.

Several cases of hypopigmentation of the skin have been reported. Most of the patients described were African or of African descent with dark skin who had been exposed to the sun. One was a Hispanic patient who developed vitiligo-like skin depigmentation after 1 month of chloroquine therapy for cutaneous lupus erythematosus. The skin rapidly repigmented after discontinuation of chloroquine therapy.

At least 2 cases of exacerbation of psoriasis requiring hospitalization have been reported. Patients with psoriasis should be cautioned about the potential for exacerbation.

Generalized exanthematous pustulosis occurred in a patient during combined chloroquine-proguanil therapy.

A 12-year-old female developed moist desquamation coincident with chloroquine therapy. She was diagnosed with a diffuse pontine glioma and considered for direct radiotherapy. Before the administration of chloroquine, the patient had only a mild skin erythema in the irradiated area, which was consistent with the radiotherapy dose she had received. On day 3 of chloroquine therapy, she developed localized brisk bullous eruptions in the irradiated area, which developed into a patch of fulminant moist desquamation. After radiotherapy was withheld for 1 week, the moist desquamation had almost healed. Chloroquine seemed to be the most probable cause for the adverse event.[Ref]

Rare (less than 0.1%): Exfoliative dermatitis, erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome, similar desquamation-type events (including moist desquamation)

Frequency not reported: Pruritus, rashes, pleomorphic skin eruptions, lichen planus-like eruptions, urticaria, generalized exanthematous pustulosis, hair loss, increased and decreased pigmentation of the skin and mucous membranes, bleaching of hair pigment, photosensitivity, exacerbation of psoriasis[Ref]


Frequency not reported: Neuropsychiatric changes, psychosis, mania, delirium, anxiety, agitation, insomnia, confusion, personality changes, depression, other psychiatric and neurologic disturbances, development of extrapyramidal rigidity, paranoia, hallucinations[Ref]

Mania has been reported in a patient taking chloroquine for malarial prophylaxis. These symptoms resolved after discontinuation and recurred with rechallenge.[Ref]


Frequency not reported: Nausea, vomiting, diarrhea, abdominal pain, abdominal cramps[Ref]

Nervous system

Frequency not reported: Mild and transient headache, convulsive seizures, polyneuritis, dizziness, nerve type deafness, tinnitus, reduced hearing (in patients with preexisting auditory damage), acute extrapyramidal disorders (e.g., dystonia, dyskinesia, tongue protrusion, torticollis), nonconvulsive status epilepticus/seizures[Ref]


Myopathies and myasthenia-like syndromes are often reversible following discontinuation or dose reduction.

These side effects were seen most often in patients receiving large doses for treatment of lupus or rheumatoid arthritis; however, such reactions have been noted in patients taking therapeutic doses for short periods. Symptoms often resolved over time with a reduction of the dose or discontinuation of chloroquine.[Ref]

Frequency not reported: Skeletal muscle myopathy or neuromyopathy leading to progressive weakness and atrophy of proximal muscle groups (may be associated with mild sensory changes, tendon reflex depression, abnormal nerve conduction), myopathies, myasthenia-like syndromes[Ref]


Rare (less than 0.1%): Hypotension, cardiomyopathy, electrocardiographic change (particularly, inversion or depression of the T-wave with widening of the QRS complex)

Frequency not reported: Cardiac hypertrophy, restrictive cardiomyopathy, congestive heart failure, complete heart block, conduction disorders[Ref]

Electrocardiographic changes observed included prolongation of the QRS interval and, rarely, complete heart block. Biopsies of cardiac tissue characteristically showed no inflammatory infiltrates, severe vacuolation, and myocytes containing myeloid bodies and lysosomes.[Ref]


Frequency not reported: Anaphylactic/anaphylactoid reaction (including angioedema), drug rash with eosinophilia and systemic symptoms (DRESS syndrome)


Frequency not reported: Anorexia, hypokalemia associated with acute ingestion, hypercalcemia associated with sarcoidosis[Ref]

The usefulness of hypokalemia as an indicator in the evaluation of chloroquine toxicity was studied in a retrospective series of 191 acute chloroquine poisonings. Results indicated that the risk of severe poisoning and death are proportional to the degree of hypokalemia.

Hypercalcemia associated with sarcoidosis has been corrected within days after the use of chloroquine.[Ref]


Rare (less than 0.1%): Pancytopenia, aplastic anemia, reversible agranulocytosis, thrombocytopenia, neutropenia[Ref]


Frequency not reported: Hepatitis, elevated liver enzymes, hepatotoxicity (in a patient with porphyria cutanea tarda)[Ref]


Frequency not reported: Pain at site of IM injections which lasted 15 minutes to 2 hours[Ref]


1. Ehrenfeld M, Nesher R, Merin S "Delayed-onset chloroquine retinopathy." Br J Ophthalmol 70 (1986): 281-3

2. Freedman DO "Clinical practice. Malaria prevention in short-term travelers." N Engl J Med 359 (2008): 603-12

3. Thorogood N, Atwal S, Mills W, et al. "The risk of antimalarials in patients with renal failure." Postgrad Med J 83 (2007): e8

4. Craig GL, Buchanan WW "Antirheumatic drugs: clinical pharmacology and therapeutic use." Drugs 20 (1980): 453-84

5. Frisk-Holmberg M, Bergkvist Y, Domeij-Nyberg B, et al "Chloroquine serum concentration and side effects: evidence for dose-dependent kinetics." Clin Pharmacol Ther 25 (1979): 345-50

6. Puavilai S, Kunavisarut S, Vatanasuk M, Timpatanapong P, Sriwong ST, Janwitayanujit S, Nantiruj K, Totemchokchyakarn K, Ruangkanchana "Ocular toxicity of chloroquine among Thai patients." Int J Dermatol 38 (1999): 934-7

7. Tonnesmann E, Stroehmann I, Kandolf R, et al. "Cardiomyopathy caused by longterm treatment with chloroquine: a rare disease, or a rare diagnosis?" J Rheumatol 39 (2012): 1099-103

8. Sassani JW, Brucker AJ, Cobbs W, Campbell C "Progressive chloroquine retinopathy." Ann Ophthalmol 15 (1983): 19-22

9. Goldstein JH "Effects of drugs on cornea, conjunctiva, and lids." Int Ophthalmol Clin 11 (1971): 13-34

10. Schlagenhauf P, Tschopp A, Johnson R, et al. "Tolerability of malaria chemoprophylaxis in non-immune travellers to sub-Saharan Africa: multicentre, randomised, double blind, four arm study." BMJ 327 (2003): 1078

11. Okor RS "Onset of pruritogenicity of chloroquine and the implication for the timing of suppressive therapy." J Clin Pharm Ther 16 (1991): 463-5

12. Rustogi A, Munshi A, Jalali R "Unexpected skin reaction induced by radiotherapy after chloroquine use." Lancet Oncol 7 (2006): 608-9

13. Olatunde IA "Chloroquine concentrations in the skin of rabbits and man." Br J Clin Pharmacol 43 (1971): 335-40

14. Janier M, Froidevaux D, LonsDanic D, Daniel F "Acute generalized exanthematous pustulosis due to the combination of chloroquine and proguanil." Dermatology 196 (1998): 271

15. Spencer HC, Poulter NR, Lury JD, Poulter CJ "Chloroquine-associated pruritus in a European." Br Med J 285 (1982): 1703-4

16. Mallett R "Risks and benefits of prophylactic antimalarial drugs." Br Med J 299 (1989): 1400

17. Ajayi AA, Akinleye AO, Udoh SJ, et al "The effects of prednisolone and niacin on chloroquine-induced pruritis in malaria." Eur J Clin Pharmacol 41 (1991): 383-5

18. Levy H "Chloroquine-induced pigmentation." S Afr Med J 62 (1982): 735-7

19. Boffa MJ, Chalmers RJG "Toxic epidermal necrolysis due to chloroquine phosphate." Br J Dermatol 131 (1994): 444-5

20. Donovan JC, Price VH "Images in clinical medicine. Chloroquine-induced hair hypopigmentation." N Engl J Med 363 (2010): 372

21. Ezeamuzie IC, Igbigbi PS, Ambakederemo AW, Abila B, Nwaejike IN "Halofantrine-induced pruritus amongst subjects who itch to chloroquine." J Trop Med Hyg 94 (1991): 184-8

22. Olsen TG "Chloroquine and psoriasis." Ann Intern Med 94 (1981): 546-7

23. Wilairatana P, Looareesuwan S, Riganti M, TejaIsavadharm P, Keeratithakul D, Eickmeyer S, Walsh DS "Pustular eruption in a malaria patient treated with chloroquine." Int J Dermatol 37 (1998): 713-4

24. Van Weelden HV, Bolling HH, De La Faille HB, et al "Photosensitivity caused by chloroquine." Arch Dermatol 118 (1982): 290

25. Martin-Garcia RF, Camacho Ndel R, Sanchez JL "Chloroquine-induced, vitiligo-like depigmentation." J Am Acad Dermatol 48 (2003): 981-3

26. Selvaag E "Chloroquine-induced vitiligo - a case report and review of the literature." Acta Derm Venereol 76 (1996): 166-7

27. Vestey JP, Savin JA "Psoriasis worsened by antimalarial prophylaxis." J Infect 24 (1992): 211-2

28. Bakshi R, Hermeling-Fritz I, Gathmann I, Alteri E "An integrated assessment of the clinical safety of artemether-lumefantrine: a new oral fixed-dose combination antimalarial drug." Trans R Soc Trop Med Hyg 94 (2000): 419-24

29. Lovestone S "Chloroquine-induced mania." Br J Psychiatry 159 (1991): 164-5

30. Akhtar S, Mukherjee S "Chloroquine induced mania." Int J Psychiatry Med 23 (1993): 349-56

31. Singh RP, Sinha AK "Neuropsychiatric toxicity of chlorquine." J Indian Med Assoc 77 (1981): 133-4

32. Mohan D, Mohandas E, Rajat R "Chloroquine psychosis: a chemical psychosis?" J Natl Med Assoc 73 (1981): 1073-6

33. Cooper RG "Chloroquine should be used with care in mental health disorders." Indian J Physiol Pharmacol 52 (2008): 97-8

34. Telgt DS, van der Ven AJ, Schimmer B, Droogleever-Fortuyn HA, Sauerwein RW "Serious psychiatric symptoms after chloroquine treatment following experimental malaria infection." Ann Pharmacother 39 (2005): 551-4

35. Liu AC "Hepatotoxic reaction to chloroquine phosphate in a patient with previously unrecognized porphyria cutanea tarda." West J Med 162 (1995): 548-51

36. Bhasin DK, Chhina RS, Sachdeva JR "Endoscopic assessment of chloroquine phosphate-induced damage to esophageal, gastric, and duodenal mucosa." Am J Gastroenterol 86 (1991): 434-7

37. Genovese MC, Becker JC, Schiff M, et al. "Abatacept for rheumatoid arthritis refractory to tumor necrosis factor alpha inhibition." N Engl J Med 353 (2005): 1114-23

38. Benbadis SR, Vanness PC "Chloroquine and nonconvulsive status epilepticus." Ann Intern Med 124 (1996): 614

39. "Product Information. Aralen (chloroquine)." Sanofi Winthrop Pharmaceuticals, New York, NY.

40. Mulhauser P, Allemann Y "Chloroquine and nonconvulsive status epilepticus." Ann Intern Med 123 (1995): 76-7

41. Robberecht W, Bednarik J, Bourgeois P, et al "Myasthenic syndrome caused by direct effect of chloroquine on neuromuscular junction." Arch Neurol 46 (1989): 464-8

42. Parodi A, Regesta G, Rebora A "Chloroquine-induced neuromyopathy." Dermatologica 171 (1985): 203-5

43. Nucci A, Queiroz LS, Samara AM "Chloroquine neuromyopathy." Clin Neuropathol 15 (1996): 256-8

44. Avinazubieta JA, Johnson ES, Suarezalmazor ME, Russell AS "Incidence of myopathy in patients treated with antimalarials. a report of three cases and a review of the literature." Br J Rheumatol 34 (1995): 166-70

45. Estes ML, Wing-Wilson D, Chou SM, et al "Chloroquine neuromyotoxicity." Am J Med 82 (1987): 447-55

46. Wasay M, Wolfe GI, Herrold JM, Burns DK, Barohn RJ "Chloroquine myopathy and neuropathy with elevated CSF protein." Neurology 51 (1998): 1226-7

47. Hearn J, Tiliakos NA "Myasthenia gravis caused by pencillamine and chloroquine therapy for rheumatoid arthritis." South Med J 79 (1986): 1185-6

48. Schirlanzoni A, Mantegazza R, Mora M, et al "Chloroquine myopathy and myasthenia-like syndrome." Muscle Nerve 11 (1988): 114-9

49. Costedoat-Chalumeau N, Hulot JS, Amoura Z, et al. "Cardiomyopathy Related to Antimalarial Therapy with Illustrative Case Report." Cardiology 107 (2006): 73-80

50. Looareesuwan S, White NJ, Chanthavanich P, et al "Cardiovascular toxicity and distribution kinetics of intravenous chloroquine." Br J Clin Pharmacol 22 (1986): 31-6

51. Ratliff NB, Este ML, Myles JL, et al "Diagnosis of chloroquine cardiomyopathy by endomyocardial biopsy." N Engl J Med 316 (1987): 191-3

52. ReussBorst M, Berner B, Wulf G, Muller GA "Complete heart block as a rare complication of treatment with chloroquine." J Rheumatol 26 (1999): 1394-5

53. Veinot JP, Mai KT, Zarychanski R "Chloroquine related cardiac toxicity." J Rheumatol 25 (1998): 1221-5

54. McAllister HA Jr, Ferrans VJ, Hall RJ et al "Cholorquine-induced cardiomyopathy." Arch Pathol Lab Med 111 (1987): 953-6

55. Baguet JP, Tremel F, Fabre M "Chloroquine cardiomyopathy with conduction disorders." Heart 81 (1999): 221-3

56. Iglesias Cubero G, Rodriguez Reguero JJ, Rojo Ortega JM "Restrictive cardiomyopathy caused by chloroquine." Br Heart J 69 (1993): 451-2

57. Buchanan N "Hypokalaemia and acute chloroquine ingestion." Lancet 347 (1996): 404

58. Clemessy JL, Borron SW, Baud FJ "Hypokalaemia and acute chloroquine ingestion - reply." Lancet 347 (1996): 404-5

59. Angel G, Berthelot PG, Rogier C "Hypokalaemia related to acute chloroquine poisoning." Lancet 346 (1995): 1625

60. Adams JS, Diz MM, Sharma OP "Effective reduction in the serum 1,25-dihydroxyvitamin D and calcium concentration in sarcoidosis-associated hypercalcemia with short-course chloroquine therapy." Ann Intern Med 111 (1989): 437-8

61. Winkelman RK, Merwin CF, Brunsting LA "Antimalarial therapy of lupus erythematosus." Ann Intern Med 55 (1961): 772-6

62. Polano MK, Cats A, van Olden GAJ "Agranulocytosis following treatment with hydroxychloroquine sulphate." Lancet 1 (1965): 1275

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.