Chloroquine Phosphate

Chloroquine Phosphate is indicated in the following cases:

• Treatment of malaria
• Prophylaxis and suppression of malaria
• Treatment of amoebic hepatitis and abscess
• Treatment of discoid and systemic and systemic lupus erythematosus
• Treatment of rheumatoid arthritis

Chloroquine is used for malarial prophylaxis (as a suppressive) and in managing acute attacks of malaria. It is highly active against erythrocytic forms of P. vivax, P. malariae and P. falciparum. It influences Hb digestion by increasing intravesicular pH in malaria parasite cells and interferes with the nucleoprotein synthesis of the patient. It is also effective in extra intestinal amoebiasis. In RA chloroquine and more effectively hydroxychloroquine have a disease-modifying effect.

Treatment of Malaria-

Partially immune adults:

A single dose of 4 tablets. In severe attacks, the dosage schedule for non-immune adults should be adopted.

Partially immune children:

• Under 1 year: 1-2 single dose (in 5 ml spoonful)
• 1-3 years: 3-4 single dose (in 5 ml spoonful)
• 3-6 years: 4-6 single dose (in 5 ml spoonful)
• 6-9 years: 6-9 single dose (in 5 ml spoonful)

In severe attacks, the dosage schedule for non-immune children should be adopted.

Non-immune adults:

• P. falciparum infections: 4 tablets initially, 2 tablets after 6 to 8 hours and then 2 tablets per day for 2 days
• P. vivax group infections: A single dose of four tablets followed by a course of treatment with primaquine phosphate (15 mg base daily for fourteen days)

Non-immune Children:

Under 1 year:

• 1-2 initial dose (in 5 ml spoonful)
• 1 dose to be taken 6 hours later and then daily for 2 days (in 5 ml spoonful)

1-3 years:

• 3-4 initial dose (in 5 ml spoonful)
• 1-2 dose to be taken 6 hours later and then daily for 2 days (in 5 ml spoonful)

3-6 years:

• 4-6 initial dose (in 5 ml spoonful)
• 2-3 dose to be taken 6 hours later and then daily for 2 days (in 5 ml spoonful)

6-9 years :

• 6-9 initial dose (in 5 ml spoonful)
• 3-5 dose to be taken 6 hours later and then daily for 2 days (in 5 ml spoonful)

 

Prophylaxis and suppression of Malaria-

Adults: 2 tablets taken once a week, on the same day each week, during exposure to risk and continued for 6 weeks after leaving the malarious area.

Children (Syrup): The following doses should be taken once a week, on the same day each week, during exposure to risk and continued for 6 weeks after leaving the malarious area.

• Under 1 year: 1 single dose (in 5 ml spoonful)
• 1-3 years: 2 single dose (in 5 ml spoonful)
• 3-6 years: 2-3 single dose (in 5 ml spoonful)
• 6-9 years: 3-5 single dose (in 5 ml spoonful)

Children (Tablets): For practical purpose, children over 12 years may be treated as adults and for those below this age, the following proportions may be applied.

• Under 1 year: ⅛ adult dose (¼ tablet)
• 1-4 years: ¼ adult dose (½ tablet)
• 4-8 years: ½ adult dose (1 tablet)
• 8-12 years: ¾ adult dose (1.5 tablet)

Concomitant therapy with phenylbutazone predisposes to dermatitis, antagonises effect of neostigmine and pyridostigmine, reduces bioavailability of ampicillin. Cimetidine inhibits metabolism of chloroquine raising plasma levels.

There is no absolute contraindication to the use of chloroquine.

Choroquine is well tolerated at the standard dosage regimens, side effects such as headache and gastrointestinal disturbances which may occur are not of a serious nature. Where prolonged high dose is required side effects can be of greater severity and patients may develop skin eruptions, occasional depigmentation or loss of hair, difficulty in accommodation, blurring of vision. Corneal opacities disappear completely when the drug is stopped. Rarely thrombocytopenia, agranulocytosis and aplastic anemia have been reported.

The most serious toxic hazard of prolonged therapy with doses is the occasional development of irreversible retinal damage. For this reason considerable caution is needed in the use of choroquine for long-term high dosage therapy and such use should only be considered when no other drug is available. Defects in visual accommodation may occur on first taking choloquine and patients should be warned regarding driving or operating machinery.

As with all other drugs, the use of choroquine during pregnancy should be avoided if possible, unless in the case of threatening infections, in the judgment of the physician, when the potential benefit outweighs the risk.

Caution is necessary when giving choroquine to patients with porphyria who also have hepatic dysfunction or cirrhosis as the drug may precipitate severe constitutional symptoms and an increase in the amount of porphyrins excreted in the urine. This reaction is especially apparent in alcoholics. Patients receiving choloquine continuously at higher dose levels for a period longer than 12 months or at weekly intervals for a period of more than 3 years as prophylactic against malaria (or the consumption exceeds 1.6 g/Kg) should undergo ophthalmic examination at three months interval.

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

Lupus erythomatosus: One tablet twice daily for one to two weeks followed by a maintenance dose of one tablet daily.

Anti-malarial drugs

Store at room temperature in a dry place, away from light.