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Hydroxychloroquine (Plaquenil)

Hydroxychloroquine (brand name:Plaquenil) is a disease-modifying anti-rheumatic drug (DMARD) approved for adults with RA. It is often given in combination with methotrexate and sulfasalazine (a treatment known as triple therapy), to help slow RA disease progression for patients who do not get relief from methotrexate therapy alone.1,2

Research shows that this medication reduces RA symptoms, including pain, swelling, and tenderness, and improves physical functioning in up to 80% of patients. Hydroxychloroquine can also decrease the frequency of RA flares.3

Hydroxychloroquine is also available in generic forms.

What are the ingredients in hydroxychloroquine?

The active ingredient in hydroxychloroquine is hydroxychloroquine sulfate.4

How does hydroxychloroquine work?

Hydroxychloroquine is an antimalarial drug. It is derived from quinine and cinchonine, which were originally taken from the bark of the cinchona tree found in Peru. Antimalarials modulate or change the way the immune system works. The exact mechanism of action for hydroxychloroquine and another antimalarial drug chloroquine in RA is not known, but researchers think these drugs decrease production of a number of different chemicals that are important to the immune response.3

What are the possible side effects of hydroxychloroquine?

Common side effects associated with hydroxychloroquine include5:

  • headache
  • dizziness
  • loss of appetite
  • nausea
  • diarrhea
  • stomach pain
  • vomiting
  • skin rash
  • hypoglycemia (low blood sugar)

If you experience any of the following symptoms while taking hydroxychloroquine, call your doctor immediately5:

  • problems seeing or reading (including if words, letters, or parts of objects are missing)
  • light sensitivity
  • blurred distance vision
  • seeing light flashes or streaks
  • difficulty hearing
  • ringing in ears
  • muscle weakness
  • bleeding or bruising of the skin
  • bleaching or loss of hair
  • mood or mental changes, including suicidal thoughts
  • irregular heartbeat
  • drowsiness
  • convulsions
  • sun sensitivity

This is not an exhaustive list of all potential side effects of hydroxychloroquine. For more information, consult your doctor or healthcare provider. If you notice any new or worsening side effects, contact your doctor or healthcare provider immediately.

Things to note about hydroxychloroquine

Before taking hydroxychloroquine, tell your doctor if you:

  • Are allergic to the medication
  • Have eye problems or vision changes, especially retinopathy
  • Are pregnant or plan to become pregnant
  • Are breastfeeding
  • Have or have ever had liver disease, psoriasis, skin inflammation, or blood problems
  • Drink large amounts of alcohol5

Serious, irreversible eye damage has occurred, though rarely, for patients taking hydroxychloroquine. Risk factors include long-term high-dose use of the medication, pre-existing severe kidney disease, age over 60. If you are taking hydroxychloroquine over a long duration, it is important to take eye exams every 6 to 12 months.6 Do not take hydroxychloroquine if you experience vision symptoms, including problems seeing or reading, light sensitivity, blurred distance vision, or light flashes or streaks.5

Certain drugs do not mix well with hydroxychloroquine, so you should tell your doctor about any other medications or supplements you are taking, including vitamins and supplements. Drugs that do not mix well include acetaminophen (Tylenol, others), digoxin (Lanoxin), iron-containing medications (including multivitamins), isoniazid (Nydrazid), methotrexate (Rheumatrex), niacin, and rifampin (Rifadin, Rimactane).v This is not a complete list of drugs that interact with hydroxychlorquine.

Dosing information

For the treatment of RA, hydroxychloroquine is typically taken by mouth once daily at 200-400 mg, although it can be taken at a higher dose. A loading dose of 1,200 mg daily, given for 6 weeks may decrease the time to clinical response. However, experts debate that this higher dosage may increase the risk of toxicity. Hydroxychloroquine can be taken in a single or divided dose (to control gastrointestinal side effects). It can also be taken with a glass of milk or meal to minimize nausea.4,5

When you take this medication, your symptoms may begin to improve in 1 to 2 months. However, it may take up to 6 months to a year before the drug achieves full effect.3,6

Written by: Sara Finkelstein | Last reviewed: September 2019.
  1. O'Dell JR, Mikuls TR, Taylor TH, et al. Therapies for active rheumatoid arthritis after methotrexate failure. N Engl J Med 2013;[published online]:1-12.
  2. Carolina Negrei, Violeta Bojinca, Andra Balanescu, et al. Management of rheumatoid arthritis: Impact and risks of various therapeutic approaches. Exp Ther Med. 2016 Apr; 11(4): 1177–1183. Published online 2016 Feb 2. doi: 10.3892/etm.2016.3045. Accessed May 20, 2018.
  3. Deane KD, West SG. Other traditional disease-modifying anti-rheumatic drugs: monotherapy and combination therapy. In: Hochberg MC, Silman AJ, Smolen JS, Weinblatt ME, Weisman MH, eds. Rheumatoid Arthritis. Philadelphia, Penn: Mosby Elsevier; 2009:325-336.
  4. Plaquenil® Hydroxychloroquine Sulfate Tablets, USP. sanofi-aventis Canada Inc., Laval, Quebec Pharmaceuticals. Revised January 29, 2018.
  5. Accessed May 20, 2018.
  6. Hydroxychloroquine. MedLine Plus. US National Library of Medicine. Bethesda, MD. Revised January 15, 2016. Accessed May 20, 2018.
  7. Hydroxychloroquine (Plaquenil). American College of Rheumatology. Updated March 2017. Accessed May 20, 2018.