Chloroquine Side Effects
Some side effects of chloroquine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to chloroquine: solution, tablet
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. 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.
Check with your doctor immediately if any of the following side effects occur while taking chloroquine:Less common
- Blurred vision
- change in vision
- eye pain
- loss of vision
- Black, tarry stools
- blood in urine or stools
- convulsions (seizures)
- cough or hoarseness
- feeling faint or lightheaded
- fever or chills
- increased muscle weakness
- lower back or side pain
- mood or other mental changes
- painful or difficult urination
- pinpoint red spots on skin
- ringing or buzzing in ears or any loss of hearing
- sore throat
- unusual bleeding or bruising
- unusual tiredness or weakness
- increased excitability
Note: The side effects in the Less Common category above may also occur or get worse after you Stop taking chloroquine.
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:More common
- difficulty in seeing to read
- itching (more common in black patients)
- loss of appetite
- nausea or vomiting
- stomach cramps or pain
- Bleaching of hair or increased hair loss
- blue-black discoloration of skin, fingernails, or inside of mouth
- skin rash
For Healthcare Professionals
Applies to chloroquine: compounding powder, injectable solution, oral tablet
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
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.
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.
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
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
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
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
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.
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.
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
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
More about chloroquine
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