Class: 4-aminoquinoline compound, Amebicide
- Tablets 500 mg chloroquine phosphate (equivalent to 300 mg base)
Inhibits parasite growth, possibly by concentrating within parasite acid vesicles, raising pH.
Rapidly and almost completely absorbed from the GI tract.
About 55% bound to nondiffusable plasma constituents. Distributed considerably into tissues (ie, liver, spleen, kidney, lung) and to a lesser extent into brain and spinal cord.
The main metabolite is desethylchloroquine.
Slowly excreted, but increased by acidification of the urine. A small amount is excreted in the feces. About 25% of the dose is excreted in urine as desethylchloroquine. More than 50% of urinary drug product is unchanged chloroquine.
Indications and Usage
Prophylaxis and treatment of acute attacks of malaria caused by Plasmodium vivax , Plasmodium malariae , Plasmodium ovale , and susceptible strains of Plasmodium falciparum ; extraintestinal amebiasis.
Treatment of rheumatoid arthritis, systemic and discoid lupus erythematosus, porphyria cutanea tarda, scleroderma, pemphigus, lichen planus, polymyositis, and sarcoidosis.
Retinal or visual field changes.
Dosage and Administration
Doses are listed in base equivalents.Acute Malaria
PO Initial dose is 600 mg, then 300 mg 6 h later and 300 mg every day for 2 days.Children
PO Initial dose is 10 mg/kg, then 5 mg/kg 6 h later and 5 mg/kg every day for 2 days.Malaria Suppression
PO 300 mg base.Children
5 mg/kg/dose (max 300 mg base) weekly. Begin 1 to 2 wk prior to exposure and continue for 4 wk after leaving endemic area. If suppressive therapy is not begun prior to exposure, double initial loading dose and give in 2 divided doses 6 h apart.Extraintestinal Amebiasis
PO 600 mg base/day for 2 days, then 300 mg base/day for 2 to 3 wk.
- Administer with food or milk.
- If taken once weekly, take on same day of week.
Store in airtight, light-resistant container at room temperature.
May increase chloroquine serum concentration.Kaolin aluminum or magnesium trisilicate antacids
May decrease GI absorption of chloroquine.Rabies vaccine
Coadministration of intradermally administered rabies vaccine and chloroquine may result in diminished antibody response to vaccine. In this situation CDC recommends administering rabies vaccine IM.
Laboratory Test Interactions
None well documented.
Hypotension; ECG changes.
Headache; neuropathy; seizures; psychotic episodes.
Pruritus; pigment changes; skin eruptions.
Visual disturbances; retinal damage and deafness with prolonged high-dose use; tinnitus.
Anorexia; nausea; vomiting; diarrhea; abdominal cramps.
Agranulocytosis; blood dyscrasias; aplastic anemia.
Perform periodic neuromuscular examinations and notify patient if knee and ankle reflexes are weak.Adverse reactions
If sore throat, fever, weakness, fatigue, or unusual bleeding or bruising occurs, notify health care provider.
Category D .
Excreted in breast milk.
Especially sensitive to adverse reactions; do not exceed recommended dose.
Special Risk Patients
Monitor patients with hepatic disease or alcoholism, or taking other hepatotoxic medications for evidence of worsening liver function such as bleeding.
May induce hemolysis in presence of infection or stressful condition.
May need to discontinue therapy if muscle weakness occurs.
Psoriasis or porphyria
May be exacerbated.
Irreversible retinal damage has occurred.
Headache, drowsiness, visual disturbances, CV collapse, seizures, respiratory and cardiac arrest, death.
- Remind patient to take medication with food to minimize GI irritation.
- Stress importance of compliance with full course of therapy. If used for suppression, drug must be taken at least 1 wk before entering and for 4 wk after leaving endemic area.
- Caution patient to drink alcoholic beverages sparingly because of increased GI irritation and higher risk of liver damage.
- Stress importance of eye examinations every 3 to 6 mo during prolonged daily therapy.
- Inform patient that drug may cause rusty or brown discoloration of urine.
- Advise use of dark glasses in bright light to reduce risk of ocular damage.
- Instruct patient to report these symptoms to health care provider: blurring or change in vision, buzzing or difficulty hearing, muscle weakness, rash, vomiting or stomach pain, difficulty breathing or swallowing.
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