Chloroquine Side Effects

Please note - some side effects for Chloroquine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Chloroquine - for the Consumer

Chloroquine

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Chloroquine:

Appetite loss; clumsiness; diarrhea; dizziness; feeling of whirling motion; mild headache; nausea; stomach cramps; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bizarre behavior; change in color or skin or inside of mouth; diarrhea; difficulty seeing and reading (words, letters, or parts of objects missing when reading); fever or sore throat; hair loss; hearing loss; mood changes; ringing in the ears; seizures; sensitivity to sunlight; unusual bleeding or bruising; unusual weakness; vision problems; weight loss.

Chloroquine Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Chloroquine Tablets:

Appetite loss; diarrhea; mild headache; nausea; stomach cramps; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue; unusual hoarseness); bizarre behavior; change in the color of the skin or the inside of mouth; difficulty seeing or reading (words, letters, or parts of objects missing when reading); dizziness; fever or sore throat; hair loss; hearing loss; mental or mood changes; red, swollen, blistered, or peeling skin; ringing in the ears; seizures; sensitivity to sunlight; symptoms of liver problems (eg, yellowing of the skin or eyes, dark urine, pale stools, persistent nausea or stomach pain); unusual bleeding or bruising; unusual weakness; vision problems (eg, blurred vision, trouble focusing); weight loss.

Chloroquine Side Effects - for the Professional

Chloroquine

Special Senses: ocular reactions: Irreversible retinal damage in patients receiving long-term or high-dosage 4-aminoquinoline therapy; visual disturbances (blurring of vision and difficulty of focusing or accommodation); 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, and fog before the eyes.

Auditory: Nerve type deafness; tinnitus, reduced hearing in patients with preexisting auditory damage.

Musculoskeletal System: 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, have been noted.

Gastrointestinal system: Anorexia, nausea, vomiting, diarrhea, abdominal cramps.

Skin and appendages: Pleomorphic skin eruptions, skin and mucosal pigmentary changes; lichen planuslike eruptions, pruritus, photosensitivity and hair loss and bleaching of hair pigment.

Hematologic system: Rarely, aplastic anemia, reversible agranulocytosis, thrombocytopenia and neutropenia

Central nervous system: Convulsive seizures. Mild and transient headache, Neuropsychiatric changes including psychosis, delirium, personality changes and depression.

Cardiovascular system: Rarely, hypotension, electrocardiographic change (particularly, inversion or depression of the T-wave with widening of the QRS complex), and cardiomyopathy.

Side Effects by Body System

Ocular

Ocular side effects have included double vision; visual disturbances (blurred vision and 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, and fog before the eyes; pigmentary retinopathy; corneal deposits; keratopathy; decreased corneal sensitivity; corneal edema; and reversible corneal opacities. Retinopathy may be dose-dependent and irreversible retinal damage has been reported in patients receiving long-term or high-dose therapy.

Retinal damage is more frequent in patients receiving the drug in high doses for prolonged periods, as in collagen vascular disease. If ocular changes are diagnosed early enough and the drug is discontinued, these changes may be reversible. Onset of retinopathy may be delayed and may actually occur after the last dose of chloroquine.

Dermatologic

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 is generally of a bluish color and 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 two 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.

Dermatologic side effects have included 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, and photosensitivity. Exfoliative dermatitis, erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome, and similar desquamation-type events (including moist desquamation) have been reported rarely. Exacerbation of psoriasis has been reported.

Psychiatric

Psychiatric side effects have included neuropsychiatric changes including psychosis, mania, delirium, anxiety, personality changes, and depression. Symptoms may persist for several months. Numerous other psychiatric and neurologic disturbances have been reported, including the development of extrapyramidal rigidity, paranoia, and hallucinations.

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

Gastrointestinal

Gastrointestinal side effects have included nausea, vomiting, diarrhea, abdominal pain and cramping, and anorexia.

Nervous system

Nervous system side effects have included mild and transient headache, convulsive seizures, polyneuritis, dizziness, nerve type deafness, tinnitus, and reduced hearing in patients with preexisting auditory damage. Insomnia, agitation, confusion, and nonconvulsive status epilepticus/seizures have also been reported.

Musculoskeletal

Musculoskeletal side effects have included skeletal muscle myopathy or neuromyopathy leading to progressive weakness and atrophy of proximal muscle groups, which may be associated with mild sensory changes, tendon reflex depression, and abnormal nerve conduction. Myopathies and myasthenia-like syndromes are often reversible following discontinuation or dose reduction.

These adverse reactions are 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 resolve over time with a reduction of the dose or discontinuation of chloroquine.

Cardiovascular

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.

Cardiovascular side effects have included hypotension, cardiac hypertrophy, cardiomyopathy (including restrictive cardiomyopathy), congestive heart failure, complete heart block, conduction disorders, and alterations in the electrocardiogram (particularly, inversion or depression of the T-wave with widening of the QRS complex).

Metabolic

Metabolic side effects have included hypokalemia associated with acute ingestion. Hypercalcemia associated with sarcoidosis has been corrected within days after the use of chloroquine.

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.

Hematologic

Hematologic side effects have rarely included pancytopenia, aplastic anemia, reversible agranulocytosis, thrombocytopenia, and neutropenia.

Hepatic

Hepatic side effects have included hepatitis and elevated liver enzymes. Hepatotoxicity in a patient with porphyria cutanea tarda has been reported.

Local

Local side effects have included pain at the site of intramuscular injections which lasted 15 minutes to 2 hours.

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