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Drug Class: Commonly Known As: Category:
Hydroxychloroquine Adult

Hydroxychloroquine - Additional Information

How LONG does it take for the medicine to be EFFECTIVE?

You may start to see improvement within a few weeks, but it may take up to several months to experience its full benefit.

What are the SPECIAL precautions while taking the medicine?

Inform your doctor or pharmacist if you have G6PD (glucose-6-phosphate dehydrogenase) deficiency or porphyria (group of diseases in which substances called porphyrins build up, negatively affecting the skin or nervous system), as Hydroxychloroquine may not be suitable for you.

STOP taking Hydroxychloroquine and let your doctor know if you develop an allergic reaction. Rash due to allergic reaction to Hydroxychloroquine is rare. Possible symptoms of allergic reaction are:

  • rash, hives, or itching
  • red, swollen, blistered or peeling skin with or without fever
  • wheezing or tightness in the chest or throat
  • trouble breathing or talking
  • unusual hoarseness
  • swelling of the mouth, face, lips, tongue or throat

STOP taking Hydroxychloroquine and seek medical attention immediately if you experience any of the rare but severe side effects:

  • Eye problems
    • Damage to the retina (cell layer at the back of the eye) may occur. Affected persons may notice blurring or loss of vision especially the centre part of an object or word, flashing light and colour deficit specifically red objects.
    • This eye problem are more likely to occur in persons with risk factors such as in those taking high doses for many years or in those with severe kidney disease. Nowadays, the dose used is lower (less than 5 mg/kg actual body weight/day) than it was originally used to treat diseases, hence, development of eye problem while taking this medicine is extremely unusual.
    • In addition, this risk is greatly reduced by regular eye check-up and following the doctor's instruction on daily dosage. Any eye changes experienced and reported early or recognised early during regular eye check-up usually improve after stopping the medicine.

While having treatment with Hydroxychloroquine, you must see your doctor as scheduled, including any eye check-up to monitor response to treatment and minimize any possible side effect.


Hydroxychloroquine may interact with other medicine or supplement that you are taking. Inform the doctor, pharmacist or specialty nurse (such as dermatology or rheumatology) before starting any medicines and supplements.

Your doctor may reduce your Colchicine dose when taken with medicines such as Tamoxifen (a medicine to treat breast cancer), as they might increase the chance of you experiencing severe side effects.

What special DIETARY instructions should I follow?

Alcohol should be avoided if possible or kept to a minimum as suggested by your rheumatologist because alcohol may increase the risk of gastrointestinal side effects associated with hydroxychloroquine.


For female patient, do inform your doctor if you are pregnant, planning for pregnancy or breastfeeding. Hydroxychloroquine can be continued during pregnancy and breastfeeding.

In SUMMARY… what you need to know about hydroxychloroquine?

  • Take hydroxychloroquine once daily, approximately the same time each day.
  • Always come for your BLOOD TESTS and EYE EXAMINATIONS on the scheduled date.
  • Beware of the SIDE EFFECTS and when to get immediate medical attention.
  • Never take medicines, supplements or herbal treatments OVER-THE-COUNTER without checking with your doctor or pharmacist first.
  • For female patient intents to start a family, please inform your doctor.
  • If you have further questions about Hydroxychloroquine, please call ______________________ (office number) to discuss with your doctor / pharmacist / specialty nurse (please circle as appropriate).
  • Updated on 6/12/2015 12:00:00 AM
  • Article contributed by Rheumatology & Immunology Singapore General Hospital
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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