Retinopathy with changes in pigmentation and visual disturbances can occur (bull's eye appearance), but it is very rare if the recommended daily dose is not exceeded. Initially it appears reversible on Hydroxychloroquine discontinuation, but if it left unchecked there will be a risk of progression even after discontinue the drug. Patients with retinal changes may be asymptomatic initially, or may have vision of scotoma with the type of paracetamol, pericentral ring, temporal scotoma and abnormal color vision at first; Visibility disorders (visual field defect/paracentral scotomas); Impaired vision (visual activity); Decreased adaptation to dark; Abnormal color vision; Blurred vision due to accommodation disorders that are dose dependent and reversible; Corneal changes including edema and unclear vision were reported. It does not cause symptoms or can cause disturbances such as halo, blurred vision or photophobia. It may be temporary and reversible at discontinuation of treatment; Cases of maculopathy and macular degeneration have been reported and may not be recovered.
Cardiomyopathy can cause heart failure and fatal events in some cases (see OVERDOSAGE and PRECAUTIONS); Chronic toxicity must be considered when conduction disorders (atrioventricular heart block) and biventricular hypertrophy are found. Withdrawal of the drug can lead to recovery; Hydroxychloroquine can extend the QT interval; Ventricular arrhythmias and torsade de pointes.
Immune system disorders:
Urticaria; Angioderma; Bronchospasm.
Skin and subcutaneous tissue disorders:
Skin rash; Pruritus; Pigmentation disorders of the skin and mucous membranes; Bleaching hair; Alopecia; Bullous eruptions including erythema multiform, Stevens-Johnson syndrome, and toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS syndrome), photosensitivity, exfoliative dermatitis, acute generalized exanthematous pustulosis (AGEP). AGEP must be distinguished from psoriasis. This is related to fever and hyperleukocytosis. The expected results usually appear after drug discontinuation.
Abdominal pain; Nausea; Diarrhea; Vomiting. These symptoms are usually treated immediately by reducing the dose or discontinue the treatment.
Nervous system disorders:
Headache; Dizziness; Convulsions have been reported in this class of drugs; Extrapyramidal disorders such as dystonia, dyskinesia, tremor (see PRECAUTIONS).
Affect instability; Restless; Psychosis; Nightmare; Irritability; Suicidal behavior.
Ear and labyrinth disorders:
Vertigo; Tinnitus; Hearing disorders.
Musculoskeletal and connective tissue disorders:
Sensorimotor disorders; Skeletal muscle myopathy or neuromyopathy which leads to progressive weakness and atrophy of proximal muscle tissue. Myopathy may be reversible after drug withdrawal, but recovery can take months; Tendon reflex depression and abnormal nerve conduction study.
Blood and lymphatic system disorders:
Bone marrow depression; Anemia; Aplastic anemia; Agranulocytosis; Leukopenia; Thrombocytopenia; Hemolysis was reported in individuals who have glucose-6-phosphate dehydrogenase (G-6-PD) deficiency.
Metabolic and nutritional disorders:
Anorexia; Hypoglycemia; Hydroxychloroquine can worsen porphyria; Decreased appetite; Weight loss.
Abnormal liver function tests; Fulminant liver failure.