Hydroxychloroquine belongs to a group of medications known as anti-inflammatories and antimalarials. It is used alone or in combination with other anti-arthritic medications to treat rheumatoid arthritis. It helps to reduce pain, stiffness, and swelling in joints. It may take several weeks before the beneficial effects of hydroxychloroquine for the treatment of rheumatoid arthritis are seen.

Hydroxychloroquine is also used to treat and prevent certain types of malaria. It may also be used for the treatment of lupus.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Recommended doses of the medication vary according to the condition being treated.

Rheumatoid arthritis: The usual adult starting dose is 400 mg to 600 mg daily. It may take several weeks before the beneficial effects of hydroxychloroquine for the treatment of rheumatoid arthritis are seen, and several months before maximum effects are achieved. After 5 to 10 days, the dose may be gradually increased. After a good response to treatment is seen (usually within 4 to 12 weeks), the dose is decreased to 200 mg to 400 mg daily.

Lupus: The usual starting dose for adults is 400 mg once or twice daily. This dose may be continued for several weeks or months depending on the benefits that occur. For long-term use, the dose of hydroxychloroquine is usually reduced to 200 mg to 400 mg daily.

Malaria: The recommended preventative adult dose is 400 mg on exactly the same day of each week, beginning 2 weeks before exposure and continued for 8 weeks after leaving the high-risk area. Children's doses are based on body weight and are calculated as 5 mg of hydroxychloroquine base per kilogram of body weight to a maximum dose of 400 mg.

For treatment of acute attacks of malaria, the recommended starting dose for adults is 800 mg followed by 400 mg after 6 to 8 hours. This is followed by 400 mg on each of the next 2 days for a total of 2,000 mg of hydroxychloroquine. Some doctors may decide to prescribe a single dose of 800 mg only, as this method has also been found effective in the treatment of malaria. Children's doses are based on body weight as prescribed by the doctor.

To help reduce stomach upset, hydroxychloroquine should be taken with a meal or a glass of milk.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is within 12 hours of your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature and keep this medication out of the reach of children.

Each white-to-off-white, capsule-shaped, biconvex, film-coated tablet, debossed with "L7" on one side and plain on the other side, contains 200 mg of hydroxychloroquine sulphate. Nonmedicinal ingredients: ammonium hydroxide, crospovidone, hypromellose, iron oxide, lactose monohydrate, magnesium stearate, polyethylene glycol, polysorbate, and shellac.

Do not take hydroxychloroquine if you:

• are allergic to hydroxychloroquine or any ingredients of the medication
• are allergic to any of the 4-aminoquinoline compounds, such as chloroquine
• have been previously diagnosed with retinopathy of the eye

Do not give this medication to children under 6 years of age.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• diarrhea
• dizziness
• hair loss
• headache
• increased skin sensitivity to sunlight
• loss of appetite
• nausea
• skin rash
• spinning sensation
• stomach cramps or pain
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blurred vision or any change in vision – this effect may also occur or worsen after stopping the medication
• change in hair or skin colour
• fainting
• hallucinations (seeing or hearing things that are not there)
• mood or other mental changes
• muscle weakness
• nervousness
• restlessness
• ringing or buzzing in ears or any loss of hearing
• shortness of breath
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of bleeding (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of heart problems (e.g., fast, irregular heartbeat or pulse, chest pain, sudden weight gain, difficulty breathing, leg swelling)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• signs of low blood sugar (hypoglycemia) (e.g., blurred vision, dizziness, fatigue, headache, numbness or tingling of the mouth, rapid heartbeat, shakiness, sweating or confusion)
• tingling, numbness, or burning pain
• tremor
• unusual tiredness or weakness

Stop taking the medication and seek immediate medical attention if any of the following occur:

• convulsions (seizures)
• extrapyramidal symptoms (abnormal body movements, restlessness, shaking, or stiffness)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, shortness of breath, or swelling of the face and throat)
• thoughts of suicide or self-harm

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood counts: This medication can decrease the number of neutrophils (a type of white blood cell that helps fight infection), red blood cells (which carry oxygen), and platelets (which help your blood to clot). If you notice any signs of infection (e.g., fever, chills, or sore throat) or unusual bleeding or bruising, contact your doctor immediately.

If you take this medication for a long period of time, your doctor will likely want you to have blood tests to monitor your levels of red and white blood cells.

Blood sugar levels: Hydroxychloroquine may cause hypoglycemia (low blood sugar levels). People with diabetes or those who are taking medications that can lower blood sugars may find it necessary to monitor their blood sugar more frequently while using this medication. People without diabetes have also been known to experience low blood sugars while taking hydroxychloroquine. If you experience signs of low blood sugar (cold sweat, cool pale skin, headache, or weakness), contact your doctor immediately.

Blurred vision: While taking this medication, use caution when driving or operating machinery, since hydroxychloroquine can cause blurring of vision. If your vision blurs, call your doctor.

Eye damage: Irreversible damage to the retina of the eye has occurred for some people who take long-term or high-dosage treatment with hydroxychloroquine. Eye damage is more likely to occur if recommended doses are exceeded. Your doctor will want you to have regular eye exams if you take this medication for a period of time. If you notice any new problems with sight or symptoms such as light flashes and streaks, stop the medication at once and call your doctor.

Heart disease: Rarely, weakening of the heart muscle has been reported with the use of hydroxychloroquine. If you have heart disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart rhythm: Hydroxychloroquine can cause changes to the normal rhythm of the heart, including an irregular heartbeat called QT prolongation. QT prolongation is a serious life-threatening condition that can cause fainting, seizures, and sudden death. If you are at risk for heart rhythm problems (e.g., people with heart failure, angina, low potassium or magnesium levels), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Hypersensitivity Reaction: Rarely, people taking hydroxychloroquine report a severe skin reaction. In rare cases, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS syndrome) may occur. This reaction involves symptoms including fever, swollen glands, yellowing of the skin or eyes, flu-like symptoms with skin rash or blistering, or other organ involvement. These reactions are medical emergencies. Get immediate medical attention if you have symptoms of a severe allergic reaction. If you experience any unusual symptoms, contact your doctor.

Kidney disease: If you have kidney disease, you may need a lower dose of this medication. Talk to your doctor about how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver disease: If you have liver disease, you may need a lower dose of this medication. Talk to your doctor about how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Muscle weakness: Call your doctor if you notice any signs of unusual or unexpected muscular weakness.

Other medical conditions: If you have epilepsy, stomach, nerve, blood, or skin disorders, talk to your doctor about how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Suicidal behaviour: Rarely, people taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. These symptoms may occur within several weeks after starting this medication. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately. You should be closely monitored by your doctor for emotional and behaviour changes while taking this medication.

Pregnancy: Hydroxychloroquine crosses the placenta during pregnancy and may cause harm to the developing baby if it is taken during pregnancy. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes in small amounts into breast milk. Infants are extremely sensitive to its side effects. If you are breast-feeding and taking hydroxychloroquine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children when used for the treatment of rheumatoid arthritis or systemic lupus erythematosus. Children are especially sensitive to the side effects of hydroxychloroquine.

Seniors: The effects of this medication on seniors have not been well studied. It is likely that people over the age of 65 will experience more side effects due to the increased likelihood of kidney, liver, or heart disease. Report any unusual effects to your doctor as soon as possible.

There may be an interaction between hydroxychloroquine and any of the following:

• acetylsalicylic acid (ASA)
• amiodarone
• anti-arrhythmic medications (e.g., amiodarone, disopyramide, dronedarone, procainamide, sotalol)
• antipsychotics (e.g., chlorpromazine, haloperidol, ziprasidone)
• azithromycin
• beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
• bismuth subsalicylate
• bromocriptine
• certain herbal products (e.g., flaxseed oil, garlic, ginger, ginseng)
• cimetidine
• cyclosporine
• dapsone
• diabetes medications (e.g., acarbose, canagliflozin, glyburide, insulin, linagliptin, liraglutide, metformin, rosiglitazone)
• digoxin
• diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
• lanreotide
• linezolid
• mefloquine
• methadone
• mifepristone
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, rasagiline, selegiline, tranylcypromine)
• octreotide
• pasireotide
• pegvisomant
• protein kinase inhibitors (e.g., lenvatinib, selpercatinib, sunitinib, vandetanib)
• quinolone antibiotics (e.g., ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin)
• rabies vaccine
• remdesivir
• ritonavir
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline, vortioxetine)
• sulfadiazine
• sulfamethoxazole
• tamoxifen
• testosterone
• tramadol
• tricyclic antidepressants (e.g., amitriptyline, imipramine)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.