Generic name: Hydroxychloroquine sulfate.

Plaquenil is an anti-inflammatory/antimalarial agent. 

Quick Facts About Plaquenil


Used to prevent and treat certain forms of malaria. Also used to treat symptoms of rheumatoid arthritis such as swelling, inflammation, stiffness, and joint pain, and for lupus erythematosus.

Plaquenil Dosage

Take exactly as prescribed, and complete the entire prescription.

  • Usual adult dose: for restraint or prevention of malaria — 400 milligrams taken once per day for 7 days. Preventive therapy should begin if possible 2 weeks before exposure. If not possible, doctor will prescribe 800 milligrams divided into 2 doses and taken 6 hours apart, continued for 8 weeks after leaving area where you may be exposed to malaria. For acute malaria attack — 800 milligrams followed by 400 milligrams in 6 to 8 hours, and 400 milligrams on each of 2 consecutive days. Alternatively, doctor may prescribe a single dose of 800 milligrams. For lupus — 400 milligrams once or twice per day, taken for several weeks or months depending on your response. Long-term therapy — 200 to 400 milligrams per day. For rheumatoid arthritis — 400 to 600 milligrams per day with food or milk. Reduced to 200 to 400 milligrams per day if condition improves within 4 to 12 weeks.
  • Usual child dose: for malaria — dose based on the child’s weight. Not prescribed to treat juvenile arthritis.
  • Missed dose: for 1 dose every 7 days — take as soon as possible, then go back to regular schedule. For 1 dose per day — take as soon as possible, unless it is the next day. In that case, do not take missed dose, go back to regular schedule. For 1 or more doses per day — take as soon as possible, if within 1 hour of missed dose. Otherwise, do not take missed dose; go back to regular schedule. Do not double doses.

Plaquenil  Side Effects

Overdose symptoms:

convulsions, drowsiness, headache, heart problems and failure, inability to breathe, visual problems. Overdose symptoms can occur within 30 minutes. If you suspect an overdose, immediately seek medical attention.

Side effects of treatment for acute malarial attack: abdominal cramps, diarrhea, dizziness, lack or loss of appetite, mild headache, nausea, vomiting. Side effects of treatment for lupus and rheumatoid arthritis: abdominal cramps, abnormal eye pigmentation, anemia, bleaching of hair, blind spots, blood disorders, blurred vision, convulsions, decreased vision, diarrhea, difficulty focusing eyes, dizziness, emotional changes, excessive coloring of skin, eye muscle paralysis, “foggy” vision, halos around lights, headache, hearing loss, involuntary eyeball movement, irritability, itching, lack of muscle coordination, light flashes and streaks, light intolerance, loss of hair, loss or lack of appetite, muscle weakness, nausea, nervousness, nightmares, psoriasis, reading difficulties, ringing in ears, skin eruptions, skin inflammation and scaling, skin rash, vertigo, vomiting, weariness, weight loss.

No known less common or rare Plaquenil  side effects.


Inform your doctor before combining Plaquenil  with:

any medication that may cause liver damage, aurothioglucose (Solganal), cimetidine (Tagamet), digoxin (Lanoxin).

No known food/other substance interactions. 

Special Cautions

Avoid use during pregnancy except when your doctor judges the benefit outweighs the risks of taking this medication. May appear in breast milk; could affect a nursing infant.

No special precautions apply to seniors.

Follow doctor’s instructions carefully for children. Should not use for long-term therapy with children.

  • Do not take if you have psoriasis or porphyria (metabolic disorder); may increase severity of these conditions. Inform your doctor if you are taking medications that may cause dermatitis.
  • If sensitive to or allergic to this or similar medications such as Aralen or Chloroquin, should not take.
  • Notify your doctor if you experience any partial or complete loss of vision in small areas while taking this or similar medications; if so, should not take.
  • Doctor should perform eye exam at start of treatment and every 3 months for prolonged therapy. May experience progression of visual disturbances after Plaquenil therapy is completed.
  • Physical examinations to determine muscle weakness should be done on a periodic basis, as should blood cell counts.
  • Inform your doctor if you experience ringing in the ears or other ear problems.
  • Medication may be discontinued if no relief for rheumatoid arthritis has occurred within 6 months.
    Use with caution if you are alcoholic and have liver or kidney problems.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Plaquenil  side effects, please contact your healthcare provider