Why is this medication prescribed?

Hydroxychloroquine is in a class of drugs called antimalarials. It is used to prevent and treat acute attacks of malaria. It is also used to treat discoid or systemic lupus erythematosus and rheumatoid arthritis in patients whose symptoms have not improved with other treatments.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

How should this medicine be used?

Hydroxychloroquine comes as a tablet to take by mouth. For prevention of malaria in adults, two tablets are usually taken once a week on exactly the same day of each week. The first dose is taken 1 to 2 weeks before traveling to an area where malaria is common, and then doses are continued for 8 weeks after exposure. For treatment of acute attacks of malaria in adults, four tablets are usually taken right away, followed by two tablets 6 to 8 hours later and then two tablets on each of the next 2 days.

For prevention or treatment of malaria in infants and children, the amount of hydroxychloroquine is based on the child's weight. Your doctor will calculate this amount and tell you how much hydroxychloroquine your child should receive.

For lupus erythematosus, one or two tablets are usually taken once or twice daily. For rheumatoid arthritis, one to three tablets are usually taken once a day.

Hydroxychloroquine can be taken with a glass of milk or a meal to decrease nausea. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take hydroxychloroquine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

If you are taking hydroxychloroquine for symptoms of rheumatoid arthritis, your symptoms should improve within 6 months. If your rheumatoid arthritis symptoms do not improve, or if they worsen, stop taking the drug and call your doctor. Once you and your doctor are sure the drug works for you, do not stop taking hydroxychloroquine without talking to your doctor. Symptoms of rheumatoid arthritis will return if you stop taking hydroxychloroquine.

Other uses for this medicine

Hydroxychloroquine is used occasionally to treat porphyria cutanea tarda. Talk to your doctor about the possible risks of using this drug for your condition.

What special precautions should I follow?

Before taking hydroxychloroquine,

• tell your doctor and pharmacist if you are allergic to hydroxychloroquine, chloroquine (Aralen), primaquine, or any other drugs.

• tell your doctor and pharmacist what prescription and nonprescription drugs you are taking, especially acetaminophen (Tylenol, others), digoxin (Lanoxin), iron-containing medications (including multivitamins), isoniazid (Nydrazid), methotrexate (Rheumatrex), niacin, rifampin (Rifadin, Rimactane), and vitamins and herbal products.

• tell your doctor if you have or have ever had liver disease, psoriasis, porphyria or other blood disorders, G-6-PD deficiency, dermatitis (skin inflammations), or if you drink large amounts of alcohol.

• tell your doctor if you have ever had vision changes while taking hydroxychloroquine, chloroquine (Aralen), or primaquine.

• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking hydroxychloroquine, call your doctor.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Hydroxychloroquine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• headache

• dizziness

• loss of appetite

• nausea

• diarrhea

• stomach pain

• vomiting

• skin rash

If you experience any of the following symptoms, call your doctor immediately:

• reading or seeing difficulties (words, letters, or parts of objects missing)

• sensitivity to light

• 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

• irregular heartbeat

• drowsiness

• convulsions

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].

What storage conditions are needed for this medicine?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

What other information should I know?

Children can be especially sensitive to an overdose, so keep the medication out of the reach of children. Children should not take hydroxychloroquine for long-term therapy.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your response to hydroxychloroquine.

If you are taking hydroxychloroquine for a long period of time, your doctor will recommend frequent eye exams. It is very important that you keep these appointments. Hydroxychloroquine can cause serious vision problems. If you experience any changes in vision, stop taking hydroxychloroquine and call your doctor immediately.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.