Overview
DESCRIPTION Chloroquine phosphate tablets, USP, is a 4-aminoquinoline compound for oral administration. It is a white, odorless, bitter tasting, crystalline substance, freely soluble in water. Chloroquine phosphate tablets are an antimalarial and amebicidal drug. Chemically, it is 7-chloro-4-[[4-(diethylamino)-1-methylbutyl]amino]quinoline phosphate (1:2) andhas the following structural formula:...
Mechanism of Action
CLINICAL PHARMACOLOGY Chloroquine is rapidly and almost completely absorbed from the gastrointestinal tract, and only a small proportion of the administered dose is found in the stools. Approximately 55% of the drug in the plasma is bound to nondiffusible plasma constituents. Excretion of chloroquine is quite slow,but is increased by acidification of the urine. Chloroquine is deposited in the tissues in considerable amounts. In animals, from 200 to 700 times the plasma concentration may be found in the liver,spleen, kidney, and lung; leukocytes also concentrate the drug. The brain and spinal cord, in contrast, contain only 10 to 30 times the amount present in plasma. Chloroquine undergoes appreciable degradation in the body.
Indications
- INDICATIONS AND USAGE Chloroquine phosphate tablets are indicated for the: Treatment of uncomplicated malaria due to susceptible strains of P. falciparum, P.malariae, P. ovale, and P.vivax . Prophylaxis of malaria in geographic areas where resistance to chloroquine is not present. Treatment of extraintestinal amebiasis. Chloroquine phosphate tablets do not prevent relapses in patients with vivax or ovale malaria because it is not effective against exoerythrocytic forms of the parasites.
Common Doses
- 500 mg
- 300 mg
- 5 mg
- 1 g
Dosage
DOSAGE AND ADMINISTRATION The dosage of chloroquine phosphate is often expressed in terms of equivalent chloroquine base. Each 500 mg tablet of Chloroquine phosphate contains the equivalent of 300 mg chloroquine base. In infants and children the dosage is preferably calculated by body weight. Prophylaxis against chloroquine-sensitive Plasmodium species Adult Dose: The dosage for prophylaxis is 500 mg (= 300 mg base) administered once per week on exactly the same day of each week.
Contraindications
- CONTRAINDICATIONS Use of chloroquine phosphate tablets for indications other than acute malaria is contraindicated in the presence of retinal or visual field changes of any etiology. Use of chloroquine phosphate tablets is contraindicated in patients with known hypersensitivity to 4-aminoquinoline compounds.
Side Effects
- ADVERSE REACTIONS The following adverse reactions have been identified during post-approval use of chloroquine or other 4-aminoqunoline compounds. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Ocular disorders: Maculopathy and macular degeneration have been reported and may be irreversible.
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.