Stop taking hydroxychloroquine sulfate and see a doctor or go to a hospital straight away if:

Not known (frequency cannot be estimated from available data)

• You have an allergic reaction. The signs may include: a red or lumpy rash, swallowing or breathing problems, swelling of the eyelids, lips, face, throat or tongue.
• Severe skin reactions such as blistering, widespread scaly skin, pus-filled spots together with a high temperature, reddening and being more sensitive to the sun.
• Blistering or peeling of the skin around the lips, eyes, mouth, nose and genitals, flu-like symptoms and fever. This could be a condition called Stevens-Johnson Syndrome.

Stop taking hydroxychloroquine sulfate and see a doctor straight away if you notice any of the following serious side effects – you may need urgent medical treatment:

Common side effects (may affect less than 1 in 10 people)

• You have any eye problems. This includes changes in the colour of your eye and problems with your eyesight such as blurring, sensitivity to light or the way you see colour.

Uncommon side effects (may affect less than 1 in 100 people)

• You have any muscle weakness, cramps, stiffness or spasms or changes in sensation such as tingling. If you take this medicine for a long time, your doctor will occasionally check your muscles and tendons to make sure they are working properly.

Not known (frequency cannot be estimated from available data)

• You have frequent infections such as fever, severe chills, sore throat or mouth ulcers. These could be signs of a blood problem called ‘leucopenia’ or ‘agranulocytosis’.
• You may bruise more easily than usual. This could be due to a blood problem called ‘thrombocytopenia’.
• You feel tired, faint or dizzy and have pale skin. These could be symptoms of something called ‘anaemia’.
• You feel weak, short of breath, bruise more easily than usual and get infections more easily than usual. These could be symptoms of something called ‘aplastic anaemia’.
• Weakening of the heart muscle (cardiomyopathy) resulting in difficulty breathing, coughing, high blood pressure, swelling, increased heart rate, low amount of urine.
• Low blood sugar levels (hypoglycaemia). You may feel a sense of nervousness, shaky or sweaty.
• You notice yellowing or your skin or your eyes or your urine becomes darker in colour. This could be a liver problem, such as jaundice or hepatitis.
• Fits.
• Lack of movement, stiffness, shaking or abnormal movements in the mouth and tongue.

Tell your doctor or pharmacist if any of the following side effects get serious or lasts longer than a few days:

Very common side effects (may affect more than 1 in 10 people)

• Stomach pain
• Feeling sick

Common side effects (may affect less than 1 in 10 people)

• Skin rashes, itching
• Being sick, diarrhoea
• Loss of appetite (anorexia)
• Headache
• Changes in mood with uncontrollable laughing or crying

Uncommon side effects (may affect less than 1 in 100 people)

• Changes in the colour of your skin or the inside of your nose or mouth
• Hair loss or loss of hair colour
• Feeling nervous
• Ringing in the ear (tinnitus)
• Balance problems (vertigo) or feeling dizzy
• Liver problems shown by blood tests

Not known (frequency cannot be estimated from available data)

• Psoriasis (red scaly patches on the skin usually affecting the knees, elbows and scalp)
• Hearing loss
• Mental problems (such as delusions, hallucinations and changes in mood)
• Symptoms of a condition called ‘porphyria’ which may include stomach pain, being sick, fits, blisters, itching

Tests

Your doctor may monitor:

• Your heart’s electrical activity using an ECG (electrocardiogram) machine.
• Your muscle function and tendon reflexes.
• The levels of specific cells in your blood using occasional blood tests. A blood test may also show changes in the way the liver is working and occasionally the liver may stop working.