* CAPITALS indicate life-threatening. Underline indicate most frequent.
Antacids may ↓ absorption (separate administration of these agents by at least 4 hr).
Blood levels may be ↑ by cimetidine, fluconazole, ketoconazole, clarithromycin, erythromycin, fluoxetine, nefazodone, paroxetine, protease inhibitors, quinidine, ritonavir, and verapamil (concurrent use with cimetidine , should be avoided).
May ↓ absorption of ampicillin (separate administration of these agents by at least 2 hr).
May ↑ levels of cyclosporine, fluoxetine, lidocaine, mirtazapine, nefazodone, paroxetine, risperidone, ritonavir, thioridazine, tricyclic antidepressants, and venlafaxine.
Carbamazepine, nevirapine, phenobarbital, phenytoin, and rifampin may ↓ levels and efficacy.
May ↑ the risk of hepatotoxicity when administered with other hepatotoxic agents.
Urinary acidifiers may ↑ renal excretion and ↓ effectiveness.
Doses below expressed as chloroquine base: 1 mg of chloroquine base = 1.67 mg chloroquine phosphate or 1.25 mg chloroquine hydrochloride
Suppression/Prophylaxis of Malaria
PO (Adults): 300 mg once weekly, starting 2 wk prior to entering endemic areas and for 8 wk afterward. If suppressive therapy is not initiated prior to entering endemic area, initial dose should be 300 mg followed by another 300 mg dose 6 hr later, followed by the usual dose regimen.
PO Children: 5 mg/kg once weekly, starting 2 wk prior to entering endemic areas and for 8 wk afterward (not to exceed 300 mg/day). If suppressive therapy is not initiated prior to entering endemic area, initial dose should be 5 mg/kg followed by another 5 mg/kg dose 6 hr later, followed by the usual dose regimen.
Treatment of Acute Attack of Malaria
PO (Adults): 600 mg initially, then 300 mg at 6–8 hr, 24 hr, and 48 hr after initial dose.
PO Children: 10 mg/kg initially (not to exceed 600 mg), then 5 mg/kg at 6 hr, 24 hr, and 48 hr after initial dose (not to exceed 300 mg/day).
PO (Adults): 600 mg once daily for 2 days, then 300 mg once daily for at least 2–3 wk (in combination with other antiprotozoals).
PO Children: 10 mg/kg (not to exceed 300 mg/day for 2–3 wk.
Rheumatoid Arthritis/Systemic Lupus Erythematosus
PO (Adults): 150 mg once daily; ↓ dosage following maximal response.
Determine baseline that includes current symptoms of disease, for future reference, prior to administration.
Assess deep tendon reflexes periodically to determine muscle weakness. If weakness occurs, discontinue therapy.
Assess hearing before starting and periodically during therapy. Discontinue therapy immediately if hearing impairment develops.
Perform ophthalmologic exam initially and periodically during therapy; discontinue therapy immediately if visual disturbances develop.
Observe for development of rash. Discontinue chloroquine at the first sign of skin reactions. Serious adverse reactions such as Stevens-Johnson syndrome or toxic epidermal necrolysis preclude further use.
Malaria: Assess patient for improvement in signs and symptoms of condition daily throughout therapy.
Rheumatoid Arthritis/Systemic Lupus Erythematosus: Assess degree of joint pain and limitation of motion monthly.
Lab Test Considerations:
Monitor CBC periodically throughout therapy. May cause ↓ WBC and platelet counts.
Monitor liver function tests periodically during therapy.
For malaria suppression/prophylaxis, chloroquine therapy start 2 wk prior to potential exposures and continued for 8 wk after leaving the area.
PO Administer with meals to minimize GI distress.
Instruct patient to take medication as directed and continue for full course of therapy, even if feeling better. Take missed doses as soon as remembered, except with regimens requiring doses more than once a day, for which missed doses should be taken within 1 hr or omitted. Do not double doses.
Review methods of minimizing exposure to mosquitoes with patients receiving chloroquine prophylactically (use insect repellent, wear long-sleeved shirt and long trousers, use screen or netting).
Advise patients to avoid use of alcohol while taking chloroquine.
Caution patient to keep chloroquine out of the reach of children; fatalities have occurred with ingestion of 3 or 4 tablets.
Explain need for periodic ophthalmic exams for patients on prolonged high-dose therapy. Advise patient that the risk of ocular damage may be decreased by the use of dark glasses in bright light. Protective clothing and sunscreen should also be used to reduce risk of dermatoses.
Advise patient to notify health care professional promptly if sore throat, fever, unusual bleeding or bruising, blurred vision, difficulty reading, visual changes, ringing in the ears, difficulty hearing, mental changes, or muscle weakness occurs or if diarrhea, anorexia, nausea, stomach pain, vomiting, or rash becomes pronounced or bothersome. Most adverse reactions are dose related.
Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding.
Rheumatoid Arthritis/Systemic Lupus Erythematosus: Instruct patient to contact health care professional if no improvement is noticed within a few days. Treatment may require up to 6 mo for full benefit.
Prevention of or improvement in signs and symptoms of malaria.
Regression of extraintestinal amebic disease.
Decrease in the symptoms and progression of rheumatoid arthritis and systemic lupus erythematosus.
chloroquine is a sample topic from the Davis's Drug Guide.
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