Chloroquine Side Effects

Not all side effects for chloroquine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to chloroquine: oral tablet

In addition to its needed effects, some unwanted effects may be caused by chloroquine. In the event that any of these side effects do occur, they may 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.

In addition to its needed effects, some unwanted effects may be caused by chloroquine. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking chloroquine:

  • Black, tarry stools
  • bleeding gums
  • blistering, peeling, or loosening of the skin
  • blood in the urine or stools
  • blurred vision
  • chest pain
  • chills
  • confusion
  • cough
  • diarrhea
  • difficulty with swallowing
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fast heartbeat
  • fever
  • headache
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • lower back or side pain
  • 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
  • skin rash, hives, or itching
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sweating
  • swollen or painful glands
  • tightness in the chest
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Incidence not known
  • Blurred vision or any other change in vision
  • change in near or distance vision
  • continuing ringing or buzzing or other unexplained noise in the ears
  • dark urine
  • difficulty in focusing the eyes
  • difficulty with speaking
  • disturbed color perception
  • double vision
  • drooling
  • general tiredness and weakness
  • halos around lights
  • hearing loss
  • inability to move the eyes
  • increased blinking or spasms of the eyelid
  • light-colored stools
  • loss of balance control
  • muscle trembling, jerking, or stiffness
  • muscular pain, tenderness, wasting, or weakness
  • nausea and vomiting
  • night blindness
  • overbright appearance of lights
  • restlessness
  • shuffling walk
  • sticking out of the tongue
  • stiffness of the limbs
  • 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
  • upper right abdominal or stomach pain
  • yellow eyes and skin

If any of the following symptoms of overdose occur while taking chloroquine, get emergency help immediately:

Symptoms of overdose
  • Chest discomfort
  • cold clammy skin
  • decreased urine
  • drowsiness
  • dry mouth
  • fainting
  • fast, slow, or irregular heartbeat
  • 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
  • sweating

Some of the side effects that can occur with chloroquine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

  • Change in hair color
  • hair loss
  • increased sensitivity of the skin to sunlight
  • redness or other discoloration of the skin
  • severe sunburn
Incidence not known
  • Abdominal or stomach cramps
  • 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.

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


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

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.


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

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


Frequency not reported: Nausea, vomiting, diarrhea, abdominal pain, abdominal cramps

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


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.

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


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

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.


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

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.


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


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


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

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