In the U.S.—

In Canada—

• Antihypercalcemic
• Antiprotozoal
• Antirheumatic, disease-modifying
• Lupus erythematosus suppressant
• Polymorphous light eruption suppressant
• Porphyria cutanea tarda suppressant

Hydroxychloroquine ( hye-drox-ee-KLOR-oh-kwin) belongs to the family of medicines called antiprotozoals. Protozoa are tiny, one-celled animals. Some are parasites that can cause many different kinds of infections in the body.

This medicine is used to prevent and to treat malaria and to treat some conditions such as liver disease caused by protozoa. It is also used in the treatment of arthritis to help relieve inflammation, swelling, stiffness, and joint pain and to help control the symptoms of lupus erythematosus (lupus; SLE).

This medicine may be given alone or with one or more other medicines. It may also be used for other conditions as determined by your doctor.

Hydroxychloroquine is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For hydroxychloroquine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to hydroxychloroquine or chloroquine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Unless you are taking it for malaria or liver disease caused by protozoa, use of this medicine is not recommended during pregnancy. In animal studies, hydroxychloroquine has been shown to cause damage to the central nervous system (brain and spinal cord) of the fetus, including damage to hearing and sense of balance, bleeding inside the eyes, and other eye problems. However, when given in low doses (once a week) to prevent malaria, this medicine has not been shown to cause birth defects or other problems in pregnant women.

Breast-feeding—A very small amount of hydroxychloroquine passes into the breast milk. It has not been reported to cause problems in nursing babies to date. However, babies and children are especially sensitive to the effects of hydroxychloroquine.

Children—Children are especially sensitive to the effects of hydroxychloroquine. This may increase the chance of side effects during treatment. Overdose is especially dangerous in children. Taking as few as 3 or 4 tablets (250-milligrams [mg] strength) of chloroquine has resulted in death in small children. Because hydroxychloroquine is so similar to chloroquine, it is probably just as toxic.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of hydroxychloroquine in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases 2 different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Blood disease (severe)—Hydroxychloroquine may cause blood disorders

• Eye or vision problems—Hydroxychloroquine may cause serious eye side effects, especially in high doses

• Glucose-6-phosphate dehydrogenase (G6PD) deficiency—Hydroxychloroquine may cause serious blood side effects in patients with this deficiency

• Kidney disease—There may be an increased chance of side effects in patients with kidney disease

• Liver disease—May decrease the removal of hydroxychloroquine from the blood, increasing the chance of side effects

• Nerve or brain disease (severe), including convulsions (seizures)—Hydroxychloroquine may cause muscle weakness and, in high doses, seizures

• Porphyria—Hydroxychloroquine may worsen the symptoms of porphyria

• Psoriasis—Hydroxychloroquine may bring on severe attacks of psoriasis

• Stomach or intestinal disease (severe)—Hydroxychloroquine may cause stomach irritation

Take this medicine with meals or milk to lessen possible stomach upset, unless otherwise directed by your doctor.

Keep this medicine out of the reach of children. Children are especially sensitive to the effects of hydroxychloroquine and overdose is especially dangerous in children. Taking as few as 3 or 4 tablets (250-mg strength) of chloroquine has resulted in death in small children. Hydroxychloroquine is probably just as dangerous.

It is very important that you take this medicine only as directed. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of serious side effects.

If you are taking this medicine to help keep you from getting malaria, keep taking it for the full time of treatment. If you already have malaria, you should still keep taking this medicine for the full time of treatment even if you begin to feel better after a few days. This will help to clear up your infection completely. If you stop taking this medicine too soon, your symptoms may return.

Hydroxychloroquine works best when you take it on a regular schedule. For example, if you are to take it once a week to prevent malaria, it is best to take it on the same day each week. Or if you are to take 2 doses a day, 1 dose may be taken with breakfast and the other with the evening meal. Make sure that you do not miss any doses. If you have any questions about this, check with your health care professional.

Dosing—

The dose of hydroxychloroquine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of hydroxychloroquine. If your dose is different, do not change it unless your doctor tells you to do so.

The number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking hydroxychloroquine.

• For tablets dosage form:
  • For prevention of malaria:
    • Adults—400 milligrams (mg) once every seven days.
    • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 6.4 mg per kilogram (kg) (2.9 mg per pound) of body weight once every seven days.
  • For treatment of malaria:
    • Adults—800 mg as a single dose. This may sometimes be followed by a dose of 400 mg six to eight hours after the first dose, then 400 mg once a day on the second and third days.
    • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 32 mg per kg (14.5 mg per pound) of body weight taken over a period of three days.
  • For treatment of arthritis:
    • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 6.5 mg per kg (2.9 mg per pound) of body weight per day.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

For patients taking hydroxychloroquine to prevent malaria:

• Your doctor may want you to start taking this medicine 1 to 2 weeks before you travel to an area where there is a chance of getting malaria. This will help you to see how you react to the medicine. Also, it will allow time for your doctor to change to another medicine if you have a reaction to this medicine.
• Also, you should keep taking this medicine while you are in the area and for 4 to 6 weeks after you leave the area. No medicine will protect you completely from malaria. However, to protect you as completely as possible, it is important to keep taking this medicine for the full time your doctor ordered. Also, if fever develops during your travels or within 2 months after you leave the area, check with your doctor immediately.

For patients taking hydroxychloroquine for arthritis or lupus:

• This medicine must be taken regularly as ordered by your doctor in order for it to help you. It may take up to several weeks before you begin to feel better. It may take up to 6 months before you feel the full benefit of this medicine.

For patients unable to swallow hydroxychloroquine tablets:

• Your pharmacist can crush the tablets and put each dose in a capsule. Contents of the capsules may then be mixed with a teaspoonful of jam, jelly, or jello. Be sure you take all the food in order to get the full dose of medicine.

Storage—

To store this medicine:

• Keep out of the reach of children. Overdose of hydroxychloroquine is very dangerous in children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Check with your doctor immediately if blurred vision, difficulty in reading, or any other change in vision occurs during or after long-term treatment. Your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor).

If your symptoms do not improve within a few days (or a few weeks or months for arthritis), or if they become worse, check with your doctor.

Hydroxychloroquine may cause blurred vision, difficulty in reading, or other change in vision. It may also cause some people to become dizzy or lightheaded. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert or able to see well. If these reactions are especially bothersome, check with your doctor.

Malaria is spread by mosquitoes. If you are living in, or will be traveling to, an area where there is a chance of getting malaria, the following mosquito-control measures will help to prevent infection:

• If possible, sleep under mosquito netting to avoid being bitten by malaria-carrying mosquitoes.
• Wear long-sleeved shirts or blouses and long trousers to protect your arms and legs, especially from dusk through dawn when mosquitoes are out.
• Apply mosquito repellent to uncovered areas of the skin from dusk through dawn when mosquitoes are out.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. When this medicine is used for short periods of time, side effects usually are rare. However, when it is used for a long time and/or in high doses, side effects are more likely to occur and may be serious.

Check with your doctor immediately if any of the following side effects occur:

• Less common
  • Blurred vision or any other change in vision—this side effect may also occur or get worse after you stop taking this medicine 
  
  

• Rare
  • Convulsions (seizures);  increased muscle weakness;  mood or other mental changes;  ringing or buzzing in ears or any loss of hearing;  sore throat and fever;  unusual bleeding or bruising;  unusual tiredness;  weakness 
  
  

• Symptoms of overdose
  • Drowsiness;  headache;  increased excitability 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Diarrhea;  difficulty in seeing to read ;  headache;  itching (more common in black patients);  loss of appetite;  nausea or vomiting;  stomach cramps or pain 
  
  

• Less common
  • Bleaching of hair or increased hair loss;  blue-black discoloration of skin, fingernails, or inside of mouth;  dizziness or lightheadedness;  nervousness or restlessness;  skin rash 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, hydroxychloroquine is used in certain patients with the following medical conditions:

• Arthritis, juvenile
• Hypercalcemia, sarcoid-associated
• Polymorphous light eruption
• Porphyria cutanea tarda
• Urticaria, solar
• Vasculitis, chronic cutaneous

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.