Hydroxychloroquine is used to prevent or treat malaria infections caused by mosquito bites. It does not work against certain types of malaria (chloroquine-resistant). The United States Center for Disease Control provides updated guidelines and travel recommendations for the prevention and treatment of malaria in different parts of the world. Discuss the most recent information with your doctor before traveling to areas where malaria occurs. This medication is also used, usually with other medications, to treat certain auto-immune diseases (lupus, rheumatoid arthritis) when other medications have not worked or cannot be used. It belongs to a class of medications known as disease-modifying antirheumatic drugs (DMARDs). It can reduce skin problems in lupus and prevent swelling/pain in arthritis, though it is not known exactly how the drug works.
Hydroxychloroquine is usually taken with food or milk to prevent stomach upset. The dosage and length of treatment are based on your medical condition and response to therapy. In children, dosage is also based on weight. For malaria prevention, take this medication by mouth once a week on the same day of the week, or as directed by your doctor. Mark a calendar to help you remember. This drug is usually started 2 weeks before entering the area with malaria. Take it once weekly while in the area, and continue taking it for 4 to 8 weeks after leaving the area or as directed by your doctor. To treat malaria, follow your doctor's instructions. For lupus or rheumatoid arthritis, take this medication by mouth, usually once or twice daily or as directed. Your doctor may gradually increase your dose. Once you have been taking the medication for a while and your condition has improved, your doctor may instruct you to lower your dose until you find the dose that works best with the fewest side effects. If you are also taking a certain drug for diarrhea (kaolin) or taking antacids (such as magnesium/aluminum hydroxide), take hydroxychloroquine at least 4 hours before or after these products. These products may bind with hydroxychloroquine, preventing your body from fully absorbing it. Use this medication regularly in order to get the most benefit from it. If you are taking it on a daily schedule, take it at the same time each day. Take this medication exactly as prescribed. Do not stop taking it without talking with your doctor, especially if you are taking it for malaria. It is important to continue taking this for the length of time prescribed. Stopping prevention or treatment too soon may lead to infection or a return of the infection. Inform your doctor if your condition persists or worsens. It may take several weeks or months to see improvement if you are taking this for lupus or arthritis. Hydroxychloroquine may not prevent malaria in all cases. If you experience fever or other symptoms of illness, seek immediate medical attention. You may need a different medication. Avoid exposure to mosquitoes. (See also Notes section.)
Nausea, stomach cramps, loss of appetite, diarrhea, dizziness, or headache may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: arm/leg/back pain, slow heartbeat, symptoms of heart failure (such as shortness of breath, swelling ankles/feet, unusual tiredness, unusual/sudden weight gain), hair loss/color change, mental/mood changes (e.g., anxiety, depression, rare thoughts of suicide, hallucinations), ringing in the ears/hearing loss, worsening of skin conditions (e.g., psoriasis), severe stomach/abdominal pain, severe nausea/vomiting, easy bleeding/bruising, signs of infection (e.g., fever, persistent sore throat), dark urine, yellowing eyes/skin. This medication may rarely cause low blood sugar (hypoglycemia). Tell your doctor right away if you develop symptoms of low blood sugar, such as sudden sweating, shaking, hunger, blurred vision, dizziness, or tingling hands/feet. If you have diabetes, be sure to check your blood sugars regularly. Your doctor may need to adjust your diabetes medication. This medication may rarely cause serious (sometimes permanent) eye problems or muscle/nerve damage, especially if you take it for a long time. Get medical help right away if you have any very serious side effects, including: sensitivity to light, vision changes (e.g., blurred vision, seeing light flashes/streaks/halos, missing/blacked-out areas of vision), muscle weakness, numbness/tingling/pain of the arms/legs. Get medical help right away if you have any very serious side effects, including: chest pain, fast/irregular heartbeat, severe dizziness, fainting, seizures. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Store at room temperature away from moisture and light. Do not store in the bathroom. Keep all medications away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
See also How to Use section. Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: ampicillin, cimetidine, digoxin, penicillamine.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include fainting, slow/fast/irregular heartbeat, extreme excitability, slow/shallow breathing, seizures, loss of consciousness.