Amoebicides.

Chloroquine - amoebic hepatitis

Tablets containing 250mg chloroquine phosphate Ph. Eur. which is equivalent to 155mg chloroquine base.

Tablets.

a) Treatment of malaria.

b) Prophylaxis and suppression of malaria.

c) Treatment of amoebic hepatitis and abscess.

d) Treatment of discoid and systemic lupus erythematosus.

e) Treatment of rheumatoid arthritis.

The dose should be taken after food.

a) Treatment of malaria

i) P. falciparum and P. malariae infections

Adults: A single dose of four tablets, followed by two tablets six hours later and then two tablets a day for two days.

Children: A single dose of 10mg base/kg, followed by 5mg base/kg six hours later and then 5mg base/kg a day for two days.

ii) P. vivax and P. ovale infections

Adults: A single dose of four tablets, followed by two tablets six hours later and then two tablets a day for two days. Follow with a course of treatment with primaquine if a radical cure is required.

Children: A single dose of 10mg base/kg, followed by 5mg base/kg six hours later and then 5mg base/kg a day for two days. Follow with a course of treatment with primaquine if a radical cure is required.

Elderly Patients: There are no special dosage recommendations for the elderly, but it may be advisable to monitor elderly patients so that optimum dosage can be individually determined.

Hepatic or Renally Impaired Patients: Caution is necessary when giving Avloclor to patients with renal disease or hepatic disease.

b) Prophylaxis and suppression of malaria

Adults: Two tablets taken once a week, on the same day each week. Start one week before exposure to risk and continue until four weeks after leaving the malarious area.

Children: A single dose of 5mg chloroquine base/kg per week on the same day each week. Start one week before exposure to risk and continue until four weeks after leaving the malarious area.

For practical purposes, children aged over 14 years may be treated as adults. The dose given to infants and children should be calculated on their body weight and must not exceed the adult dose regardless of weight.

1 - 4 years ½ tablet

5 - 8 years 1 tablet

9 - 15 years 1½ tablets

Elderly Patients: There are no special dosage recommendations for the elderly, but it may be advisable to monitor elderly patients so that optimum dosage can be individually determined.

Hepatic or Renally Impaired Patients: Caution is necessary when giving Avloclor to patients with renal disease or hepatic disease.

c) Amoebic hepatitis

Adults: Four tablets daily for two days followed by one tablet twice daily for two or three weeks.

Elderly Patients: There are no special dosage recommendations for the elderly, but it may be advisable to monitor elderly patients so that optimum dosage can be individually determined.

Hepatic or Renally Impaired Patients: Caution is necessary when giving Avloclor to patients with renal disease or hepatic disease.

d) Lupus erythematosus

Adults: One tablet twice daily for one to two weeks followed by a maintenance dosage of one tablet daily.

Elderly Patients: There are no special dosage recommendations for the elderly, but it may be advisable to monitor elderly patients so that optimum dosage can be individually determined.

Hepatic or Renally Impaired Patients: Caution is necessary when giving Avloclor to patients with renal disease or hepatic disease.

e) Rheumatoid arthritis

Adults: The usual dosage is one tablet daily.

Elderly Patients: There are no special dosage recommendations for the elderly, but it may be advisable to monitor elderly patients so that optimum dosage can be individually determined.

Hepatic or Renally Impaired Patients: Caution is necessary when giving Avloclor to patients with renal disease or hepatic disease.

Not recommended.

Known hypersensitivity to chloroquine or any other ingredients of the formulation.

When used as malaria prophylaxis official guidelines and local information on prevalence of resistance to anti-malarial drugs should be taken into consideration.

Caution is necessary when giving Avloclor to patients with impaired hepatic function, particularly when associated with cirrhosis.

Caution is also necessary in patients with porphyria. Avloclor may precipitate severe constitutional symptoms and an increase in the amount of porphyrins excreted in the urine. This reaction is especially apparent in patients with high alcohol intake.

Caution is necessary when giving Avloclor to patients with renal disease.

Avloclor should be used with care in patients with a history of epilepsy. Potential risks and benefits should be carefully evaluated before use in subjects on anticonvulsant therapy or with a history of epilepsy as rare cases of convulsions have been reported in association with chloroquine.

Considerable caution is needed in the use of Avloclor for long-term high dosage therapy and such use should only be considered when no other drug is available. Patients on long-term therapy should also be monitored for cardiomyopathy.

Irreversible retinal damage and corneal changes may develop during long term therapy and after the drug has been discontinued. Ophthalmic examination prior to and at 3 – 6 monthly intervals during use is required if patients are receiving chloroquine

• at continuous high doses for longer than 12 months

• as weekly treatment for longer than 3 years

• when total consumption exceeds 1.6g/kg (cumulative dose 100g)

Full blood counts should be carried out regularly during extended treatment as bone marrow suppression may occur rarely. Caution is required if drugs known to induce blood disorders are used concurrently.

The use of Avloclor in patients with psoriasis may precipitate a severe attack.

Caution is advised in patients with glucose-6-phosphate dehydrogenase deficiency, as there may be a risk of haemolysis.

If the patient is taking cyclosporin then chloroquine may cause an increase in cyclosporin levels.

Pre-exposure intradermal human diploid-cell rabies vaccine should not be administered to patients taking chloroquine as this may suppress the antibody response. When vaccinated against rabies, that vaccine should precede the start of the antimalarial dosing, otherwise the effectiveness of the vaccine might be reduced.

Chloroquine significantly reduces levels of praziquantel. Caution is therefore advised during co-administration. Prescribers may consider increasing the dose of praziquantel if the patient does not respond to the initial dose.

Antacids (aluminium, calcium and magnesium salts) may reduce the absorption of chloroquine, so antacids should be taken well separated from Avloclor (at least two hours before or after).

The adverse reactions which may occur at doses used in the prophylaxis or treatment of malaria are generally not of a serious nature. Where prolonged high dosage is required, i.e. in the treatment of rheumatoid arthritis, adverse reactions can be of a more serious nature.

Cardiovascular: hypotension and ECG changes (at high doses) cardiomyopathy.

Central nervous system: convulsions and psychotic reactions including hallucinations (rare), anxiety, personality changes.

Eye disorders: retinal degeneration, macular defects of colour vision, pigmentation, optic atrophy scotomas, field defects, blindness, corneal opacities and pigmented deposits, blurring of vision, difficulty in accommodation, diplopia.

Gastro-intestinal: gastro-intestinal disturbances, nausea, vomiting, diarrhoea, abdominal cramps.

General: headache.

Haematological: bone marrow depression, aplastic anaemia, agranulocytosis, thrombocytopenia, neutropenia.

Hepatic: Changes in liver function, including hepatitis and abnormal liver function tests, have been reported rarely.

Hypersensitivity: allergic and anaphylactic reactions, including urticaria, angioedema and vasculitis.

Hearing disorders: tinnitus, reduced hearing, nerve deafness.

Muscular: neuromyopathy and myopathy.

Skin: macular, urticarial and purpuric skin eruptions, occasional depigmentation or loss of hair, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, precipitation of psoriasis, pruritus, photosensitivity, lichen-planus type reaction, pigmentation of the skin and mucous membranes (long term use).

AstraZeneca

(POM)

26 June 2009