Get emergency medical help if you have signs of an allergic reaction to hydroxychloroquine (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).
Also seek emergency medical attention if you have symptoms of a serious heart problem: fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out).
Call your doctor at once if you have:
a seizure;
yellowing of your eyes;
ringing in your ears, trouble hearing;
unusual mood changes;
severe muscle weakness, loss of coordination, underactive reflexes;
low blood cell counts - fever, chills, tiredness, sore throat, mouth sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;
low blood sugar - headache, hunger, sweating, irritability, dizziness, fast heart rate, and feeling anxious or shaky; or
a serious drug reaction that can affect many parts of your body - skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.
Taking hydroxychloroquine long-term or at high doses may cause irreversible damage to the retina of your eye. Stop taking hydroxychloroquine and tell your doctor if you have:
blurred vision, trouble focusing, trouble reading;
distorted vision, blind spots;
changes in your color vision;
hazy or cloudy vision;
seeing light flashes or streaks, seeing halos around lights; or
increased sensitivity to light.
Common hydroxychloroquine side effects may include:
headache, dizziness;
nausea, vomiting, stomach pain;
loss of appetite, weight loss;
feeling nervous or irritable;
skin rash or itching; or
hair loss.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Hydroxychloroquine side effects (more detail)
