1. patients under 18 years old; 2. hospitalization at the first medical care; 3. positive test for influenza at the first medical care; 4. known hypersensitivity to hydroxychloroquine / chloroquine; 5. previous diagnosis of retinopathy or macular degeneration; 6. previous diagnosis of long qt-syndrome, history of sudden death in close family members (parents and siblings), decompensated heart failure, unstable coronary artery disease, use of anti-arrhythmic drugs or other drugs that can increase the hydroxychloroquine bioavailability or enhance its effect; 7. evidence of known liver disease, reported by the patient; 8. evidence of known chronic kidney disease, reported by the patient; 9. patients with pancreatitis; 10. baseline ecg with qtc interval ≥ 480ms; 11. chronic use of hydroxychloroquine/chloroquine for other reasons; 12. pregnancy.

1. patients under 18 years old; 2. hospitalization at the first medical care; 3. positive test for influenza at the first medical care; 4. known hypersensitivity to hydroxychloroquine / chloroquine; 5. previous diagnosis of retinopathy or macular degeneration; 6. previous diagnosis of long qt-syndrome, history of sudden death in close family members (parents and siblings), decompensated heart failure, unstable coronary artery disease, use of anti-arrhythmic drugs or other drugs that can increase the hydroxychloroquine bioavailability or enhance its effect; 7. evidence of known liver disease, reported by the patient; 8. evidence of known chronic kidney disease, reported by the patient; 9. patients with pancreatitis; 10. baseline ecg with qtc interval ≥ 480ms; 11. chronic use of hydroxychloroquine/chloroquine for other reasons; 12. pregnancy.

patients under 18 years old; hospitalization at the first medical care; positive test for influenza at the first medical care; known hypersensitivity to hydroxychloroquine / chloroquine; previous diagnosis of retinopathy or macular degeneration; previous diagnosis of long qt-syndrome, history of sudden death in close family members (parents and siblings), decompensated heart failure, unstable coronary artery disease, use of anti-arrhythmic drugs or other drugs that can increase the hydroxychloroquine bioavailability or enhance its effect; evidence of known liver disease, reported by the patient; evidence of known chronic kidney disease, reported by the patient; patients with pancreatitis; baseline ecg with qtc interval ≥ 480ms; chronic use of hydroxychloroquine/chloroquine for other reasons; pregnancy.

patients under 18 years old; hospitalization at the first medical care; positive test for influenza at the first medical care; known hypersensitivity to hydroxychloroquine / chloroquine; previous diagnosis of retinopathy or macular degeneration; previous diagnosis of long qt-syndrome, history of sudden death in close family members (parents and siblings), decompensated heart failure, unstable coronary artery disease, use of anti-arrhythmic drugs or other drugs that can increase the hydroxychloroquine bioavailability or enhance its effect; evidence of known liver disease, reported by the patient; evidence of known chronic kidney disease, reported by the patient; patients with pancreatitis; baseline ecg with qtc interval ≥ 480ms; chronic use of hydroxychloroquine/chloroquine for other reasons; pregnancy.

1. patients under 18 years old; 2. hospitalization at the first medical care; 3. positive test for influenza at the first medical care; 4. known hypersensitivity to hydroxychloroquine / chloroquine; 5. previous diagnosis of retinopathy or macular degeneration; 6. previous diagnosis of long qt-syndrome, history of sudden death in close family members (parents and siblings), decompensated heart failure, unstable coronary artery disease, use of anti-arrhythmic drugs or other drugs that can increase the hydroxychloroquine bioavailability or enhance its effect; 7. evidence of known liver disease, reported by the patient; 8. evidence of known chronic kidney disease, reported by the patient; 9. patients with pancreatitis; 10. baseline ecg with qtc interval ≥ 480ms; 11. chronic use of hydroxychloroquine/chloroquine for other reasons; 12. pregnancy.

1. patients under 18 years old; 2. hospitalization at the first medical care; 3. positive test for influenza at the first medical care; 4. known hypersensitivity to hydroxychloroquine / chloroquine; 5. previous diagnosis of retinopathy or macular degeneration; 6. previous diagnosis of long qt-syndrome, history of sudden death in close family members (parents and siblings), decompensated heart failure, unstable coronary artery disease, use of anti-arrhythmic drugs or other drugs that can increase the hydroxychloroquine bioavailability or enhance its effect; 7. evidence of known liver disease, reported by the patient; 8. evidence of known chronic kidney disease, reported by the patient; 9. patients with pancreatitis; 10. baseline ecg with qtc interval ≥ 480ms; 11. chronic use of hydroxychloroquine/chloroquine for other reasons; 12. pregnancy.