Hydroxychloroquine is used to prevent and treat acute attacks of malaria. It is also used to treat discoid lupus erythematosus (DLE; a chronic inflammatory condition of the skin) or systemic lupus erythematosus (SLE; a chronic inflammatory condition of the body) and rheumatoid arthritis in patients whose symptoms have not improved with other treatments. Hydroxychloroquine is in a class of drugs called antimalarials. It works by killing the organisms that cause malaria. Hydroxychloroquine may work to treat rheumatoid arthritis and systemic lupus erythematosus by decreasing the activity of the immune system.

Hydroxychloroquine comes as a tablet to take by mouth. If you are an adult and taking hydroxychloroquine to prevent malaria, one dose is usually taken once a week on exactly the same day of each week. You will begin treatment 1 to 2 weeks before you travel to an area where malaria is common and then continue during your time in the area and for 4 weeks after you return. If you are an adult and taking hydroxychloroquine to treat malaria, the first dose is usually taken right away, followed by another dose 6 to 8 hours later and then additional doses 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.

If you are taking hydroxychloroquine to treat lupus erythematosus (DLE or SLE), it is usually taken once or twice a day. If you are taking hydroxychloroquine to treat rheumatoid arthritis, it is usually taken once or twice a day.

Swallow the tablets whole; do not split, chew, or crush them.

Hydroxychloroquine tablets 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.

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

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

Before taking hydroxychloroquine,

• Tell your doctor and pharmacist if you are allergic to hydroxychloroquine, chloroquine, primaquine, quinine, or any other drugs.
• Tell your doctor and pharmacist what prescription and nonprescription drugs, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention acetaminophen (Tylenol, others); azithromycin (Zithromax); cimetidine (Tagamet); cyclosporine (Gengraf, Neoral, Sandimmune); digoxin (Lanoxin), insulin and oral medication for diabetes; medications for seizures such as carbamazepine (Carbatrol, Epitol, Equetro, Tegretol, Teril), phenytoin (Dilantin, Phenytek), or valproic acid (Depakene); certain medications for irregular heartbeat such as amiodarone (Pacerone); methotrexate (Trexall, Xatmep); moxifloxacin (Avelox); praziquantel (Biltricide); and tamoxifen (Nolvadex). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with hydroxychloroquine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• If you are taking antacids, take them 4 hours before or 4 hours after hydroxychloroquine. If you are taking ampicillin, take it at least 2 hours before or 2 hours after hydroxychloroquine.
• Tell your doctor if you have or have ever had liver disease, heart disease, a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death), an irregular heartbeat, a low level of magnesium or potassium in your blood, psoriasis, porphyria or other blood disorders, G-6-PD deficiency (an inherited blood disease), dermatitis (skin inflammations), seizures, vision problems, diabetes, kidney problems, 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.

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.

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
• Rash

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

• Difficulty reading or seeing (words, letters, or parts of objects missing)
• Sensitivity to light
• Blurred vision
• Changes in vision
• Seeing light flashes or streaks
• Difficulty hearing
• Ringing in ears
• Muscle weakness
• Unusual bleeding or bruising
• Bleaching or loss of hair
• Mood or mental changes
• Irregular heartbeat
• Drowsiness
• Convulsions
• Decreased consciousness or loss of consciousness
• Thinking about harming or killing yourself

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 (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

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).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• Headache
• Drowsiness
• Visual disturbances
• Convulsions
• Irregular heartbeat

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 and electrocardiograms (EKG, a test to monitor your heart rate and rhythm) 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.