Chloroquine Phosphate
Indications
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
Pharmacology
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.
Dosage & Administration
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)
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)
- 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)
- 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 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)
- 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)
Interaction
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.
Contraindications
There is no absolute contraindication to the use of chloroquine.
Side Effects
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.
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.
Pregnancy & Lactation
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.
Precautions & Warnings
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.
Use in Special Populations
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.
Lupus erythomatosus: One tablet twice daily for one to two weeks followed by a maintenance dose of one tablet daily.
Therapeutic Class
Anti-malarial drugs
Storage Conditions
Store at room temperature in a dry place, away from light.
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