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Drugs reference index «Hydroxychloroquine sulfate»

Hydroxychloroquine sulfate

Brand names: Plaquenil

Why is Hydroxychloroquine sulfate prescribed?

Plaquenil is prescribed for the prevention and treatment of certain forms of malaria.

Plaquenil is also used to treat the symptoms of rheumatoid arthritis such as swelling, inflammation, stiffness, and joint pain. It is also prescribed for lupus erythematosus, a chronic inflammation of the connective tissue.

Most important fact about Hydroxychloroquine sulfate

Children are especially sensitive to Plaquenil. Relatively small doses of Hydroxychloroquine sulfate have caused fatalities. Keep Hydroxychloroquine sulfate in a child-proof container and out of the reach of children.

How should you take Hydroxychloroquine sulfate?

Take Plaquenil exactly as prescribed for the full course of therapy.

If you have been prescribed Plaquenil for rheumatoid arthritis, it will take several weeks for beneficial effects to appear. Take each dose with a meal or a glass of milk.

  • If you miss a dose...And you take 1 dose every 7 days, take it as soon as you remember, then go back to your regular schedule.

If you take 1 dose a day and you miss your dose, take it as soon as you remember. If you do not remember until the next day, skip the one you missed and go back to your regular schedule.

If you take more than one dose a day, take it as soon as you remember if it is within an hour or so of the missed time. If you do not remember until later on, skip the missed dose and go back to your regular schedule. Do not take 2 doses at once.

  • Storage information...Store at room temperature, away from heat, light, and moisture.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Plaquenil.

  • Side effects of treatment for an acute malarial attack may include:Abdominal cramps, diarrhea, dizziness, heart problems, lack or loss of appetite, mild headache, nausea, vomiting
  • Side effects of treatment for lupus erythematosus and rheumatoid arthritis may include:Abdominal cramps, abnormal eye pigmentation, acne, anemia, bleaching of hair, blind spots, blisters in mouth and eyes, blood disorders, blurred vision, convulsions, decreased vision, diarrhea, difficulty focusing the eyes, diminished reflexes, dizziness, emotional changes, excessive coloring of the skin, eye muscle paralysis, "foggy vision," halos around lights, headache, hearing loss, heart problems, hives, involuntary eyeball movement, irritability, itching, light flashes and streaks, light intolerance, liver problems or failure, loss of hair, loss or lack of appetite, muscle paralysis, muscle weakness and wasting, nausea, nervousness, nightmares, psoriasis (dry, scaly, red skin patches), reading difficulties, ringing in the ears, skin eruptions, skin inflammation and scaling, skin rash, vertigo, vomiting, weariness, weight loss

Why should Hydroxychloroquine sulfate not be prescribed?

If you are sensitive to or have ever had an allergic reaction to Plaquenil or similar drugs, you should not take Hydroxychloroquine sulfate. Make sure your doctor is aware of any drug reactions you have experienced.

Plaquenil should not be prescribed if you have suffered partial or complete loss of vision in small areas while taking Hydroxychloroquine sulfate or similar drugs. Notify your doctor of any past or present visual changes you have experienced.

This drug should not be used for long-term therapy in children.

Special warnings about Hydroxychloroquine sulfate

Unless you are directed to do so by your doctor, do not take Hydroxychloroquine sulfate if you have psoriasis (a recurrent skin disorder characterized by patches of red, dry, scaly skin) or porphyria (an inherited metabolic disorder affecting the liver or bone marrow). The use of Plaquenil may cause a severe attack of psoriasis and may increase the severity of porphyria.

Disorders of the retina causing impairment or loss of vision may be related to the length of time and the dose of Plaquenil given for lupus and rheumatoid arthritis. Problems have occurred several months to several years after beginning daily therapy. When you are on prolonged therapy your doctor will perform eye examinations at the beginning of treatment and every 3 months after that. Visual disturbances may progress, even after you have stopped taking Hydroxychloroquine sulfate. If you have any problem with your vision or your eyes, notify your doctor immediately.

All people on long-term therapy with Hydroxychloroquine sulfate should have a physical examination periodically, including testing of knee and ankle reflexes, to detect any evidence of muscular weakness.

Consult your doctor if you experience ringing in the ears, or other hearing problems.

If you are being treated for rheumatoid arthritis and have shown no improvement (such as reduced joint swelling or increased mobility) within 6 months, your doctor may decide to discontinue Hydroxychloroquine sulfate.

Plaquenil should be used with caution by alcoholics and those who have liver disease or kidney problems.

Your doctor should conduct periodic blood cell counts if you are on prolonged therapy with Hydroxychloroquine sulfate. If any severe blood disorder develops that is not attributed to the disease you are being treated for, your doctor may discontinue use of Hydroxychloroquine sulfate.

Consult your doctor if you are taking a drug that has a tendency to produce dermatitis (inflammation of the skin), because you may have some skin reactions while taking Plaquenil.

Possible food and drug interactions when taking Hydroxychloroquine sulfate

If Plaquenil is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Plaquenil with the following:

Any medication that may cause liver damageAurothioglucoseCimetidineDigoxin

Special information if you are pregnant or breastfeeding

Use of Hydroxychloroquine sulfate during pregnancy should be avoided except in the suppression or treatment of malaria when, in the judgment of your doctor, the benefit outweighs the possible hazard. This drug may appear in breast milk and could affect a nursing infant. If Hydroxychloroquine sulfate is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment is finished.

Recommended dosage for Hydroxychloroquine sulfate


Restraint or Prevention of Malaria

The usual dose is 400 milligrams taken once every 7 days on exactly the same day of each week. If circumstances permit, preventive therapy should begin 2 weeks prior to exposure. If this is not possible, your doctor will have you take a starting dose of 800 milligrams, which may be divided into 2 doses taken 6 hours apart. You should continue this suppressive therapy for 8 weeks after leaving the area where malaria occurs.

Acute Attack of Malaria

The usual starting dose is 800 milligrams, to be followed by 400 milligrams in 6 to 8 hours and 400 milligrams on each of 2 consecutive days.

Alternatively, your doctor may prescribe a single dose of 800 milligrams.

Lupus Erythematosus

The usual starting dose for adults is 400 milligrams once or twice daily. You will continue to take this dose for several weeks or months, depending on your response. For longer-term maintenance therapy, your doctor may reduce the dose to 200 to 400 milligrams per day.

Rheumatoid Arthritis

The usual starting dose for adults is 400 to 600 milligrams a day taken with a meal or a glass of milk. If your condition improves, usually within 4 to 12 weeks, your doctor will reduce the dose to a maintenance level of 200 to 400 milligrams daily.


For the treatment of malaria, your doctor will calculate the dosage on the basis of your child's weight.

This drug has not been proved safe for treatment of juvenile arthritis.


Any medication taken in excess can have serious consequences. If you suspect an overdose, seek emergency medical treatment immediately.

  • Symptoms of an overdose of Plaquenil may occur within 30 minutes. They include:Convulsions, drowsiness, headache, heart problems and failure, inability to breathe, visual problems
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