BMA Concise Guide to Medicine & Drugs

Chloroquine

Brand names Avloclor, Malarivon, Nivaquine

Used in the following combined preparation Paludrine/Avloclor

QUICK REFERENCE

Drug group Antimalarial drug and disease-modifying antirheumatic drug

Overdose danger rating High

Dependence rating Low

Prescription needed No (malaria prevention); Yes (other uses)

Available as generic Yes

GENERAL INFORMATION

Chloroquine is used for the prevention and treatment of malaria. It usually clears an attack in three days. Injections may be given for a severe attack. To prevent malaria, a low dose is given once weekly, starting one week before visiting a high-risk area and continuing through four weeks after leaving. Chloroquine is not suitable for use in all parts of the world as resistance to the drug has developed in some areas. The other main use is in the treatment of autoimmune diseases, such as rheumatoid arthritis and lupus erythematosus.

Common side effects include nausea, headache, diarrhoea, and abdominal cramps. Occsionally a rash develops. Chloroquine can damage the retina during prolonged treatment, causing blurred vision that may progress to blindness. Regular eye examinations are performed to detect early changes.

INFORMATION FOR USERS

Follow instructions on the label. Call your doctor if symptoms worsen.

How taken/used Tablets, liquid, injection.

Frequency and timing of doses By mouth 1 x weekly (prevention of malaria); 1–2 x daily (treatment of malaria); 1 x daily (arthritis); 1–2 x daily (lupus erythematosus).

Adult dosage range Prevention of malaria 310mg (2 tablets) as a single dose on the same day each week. Start 1 week before entering endemic area, and continue for 4 weeks after leaving. Treatment of malaria Initial dose 620mg (4 tablets) and following doses 310mg. Rheumatoid arthritis 150mg (1 tablet) per day.

Onset of effect 2–3 days. In rheumatoid arthritis, full effect may not be felt for up to 6 months.

Duration of action Up to 1 week.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember but if your next dose is due within 24 hours (1 x weekly schedule), or 6 hours (1–2 x daily schedule), take a single dose now and skip the next.

Stopping the drug Do not stop the drug without consulting your doctor.

OVERDOSE ACTION

Seek immediate medical advice in all cases. Take emergency action if breathing difficulties, seizures, or loss of consciousness occur.

POSSIBLE ADVERSE EFFECTS

Common side effects, such as nausea, diarrhoea, and abdominal pain, may be avoided by taking the drug with food. More rarely, chloroquine may cause dizziness, hearing problems, hair loss, or depigmentation of the skin; if so, you should consult your doctor. If you develop a rash or notice any changes in vision, stop taking the drug and consult your doctor promptly.

INTERACTIONS

Ciclosporin and digoxin Chloroquine increases blood levels of these drugs.

Antiepileptic drugs Chloroquine may reduce the effect of these drugs.

Amiodarone, bosutinib, droperidol, and moxifloxacin Chloroquine may increase the risk of abnormal heart rhythms if taken with these drugs.

Mefloquine may increase the risk of seizures if taken with chloroquine.

SPECIAL PRECAUTIONS

Be sure to consult your doctor or pharmacist before taking this drug if:

· You have liver or kidney problems.

· You have glucose-6-phosphate dehydrogenase (G6PD) deficiency.

· You have eye or vision problems.

· You have psoriasis.

· You have a history of epilepsy.

· You suffer from porphyria.

· You are taking other medicines.

Pregnancy No evidence of risk with low doses. High doses may affect the baby. Discuss the benefits versus the risks of malaria prevention with your doctor.

Breast-feeding The drug may pass into breast milk in small amounts. At normal doses, effects on the baby are unlikely. At high doses in the long term, discuss with your doctor.

Infants and children Reduced dose necessary.

Over 60 No special problems, except that it may be difficult to tell between changes in eyesight due to ageing, and those that are drug induced.

Driving and hazardous work Avoid such activities until you have learned how chloroquine affects you because the drug may cause dizziness and changes in vision.

Alcohol Keep consumption low.

PROLONGED USE

Prolonged use may cause eye damage and blood disorders.

Monitoring Periodic eye tests and blood counts must be carried out.