Nurses Compass
Drug Guide
Chloroquine Hydrochloride
Classification
Therapeutic: Antimalarial agent
Pharmacological: Aminoquinoline antimalarial
FDA Approved Indications
- Prophylaxis of malaria
- Treatment of uncomplicated Plasmodium vivax, P. ovale, P. malariae, and sensitive strains of P. falciparum malaria
Mechanism of Action
Chloroquine accumulates in the parasite's food vacuoles, inhibiting heme polymerization, leading to accumulation of toxic heme, which destroys the parasite.
Dosage and Administration
Adult: For malaria prophylaxis: 500 mg chloroquine base (equivalent to 620 mg chloroquine phosphate) once weekly starting 1-2 weeks before travel, continuing during travel and for 4-6 weeks after leaving endemic area. For treatment: 600 mg base (750 mg phosphate) initially, then 300 mg base (375 mg phosphate) at 6, 24, and 48 hours.
Pediatric: Dosage varies with weight and age; typically, 10 mg/kg chloroquine base (12.5 mg/kg phosphate) for the initial dose, then 5 mg/kg (6.25 mg/kg phosphate) at 6, 24, and 48 hours.
Geriatric: Use with caution; dose adjustments based on renal and hepatic function may be necessary.
Renal Impairment: Adjust dose as necessary; monitor for toxicity.
Hepatic Impairment: Use cautiously due to potential accumulation.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Wide distribution; crosses the placenta and enters breast milk.
Metabolism: Primarily hepatic.
Excretion: Renal and biliary routes.
Half Life: Approximately 1-2 months, due to large volume of distribution.
Contraindications
- History of hypersensitivity to chloroquine or other 4-aminoquinolines
- Retinal or visual field changes from previous therapy
Precautions
- Use cautiously in patients with hepatic or renal impairment, psoriasis, or a history of epilepsy. Monitor ocular health during prolonged use.
- Pregnancy Category C; benefit-risk assessment needed.
Adverse Reactions - Common
- Nausea, vomiting, diarrhea (Common)
- Headache, dizziness (Common)
Adverse Reactions - Serious
- Retinal toxicity, irreversible visual damage (Rare but serious)
- Cardiac toxicity, including QT prolongation and arrhythmias (Rare but serious)
- Seizures, hemolytic anemia in G6PD deficiency (Rare)
Drug-Drug Interactions
- Coadministration with other drugs that prolong QT interval (e.g., quinidine, amiodarone) increases risk of arrhythmias.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Baseline ocular examination, assessment of renal and hepatic function, G6PD deficiency testing.
Diagnoses:
- Risk of retinal toxicity
- Risk of cardiac arrhythmias
Implementation: Monitor for adverse effects, patient education on visual changes, periodic eye exams during prolonged therapy.
Evaluation: Regular ophthalmologic assessments and monitoring for adverse reactions.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any visual changes, hearing loss, or unusual side effects immediately.
- Avoid alcohol and medications that can prolong QT interval unless approved by healthcare provider.
Special Considerations
Black Box Warnings:
- Potential for irreversible retinal damage; ophthalmologic examinations needed during prolonged therapy.
- Falciparum malaria may be resistant; confirm susceptibility before use.
Genetic Factors: G6PD deficiency can increase risk of hemolytic anemia.
Lab Test Interference: May interfere with some serologic and blood tests.
Overdose Management
Signs/Symptoms: Nausea, vomiting, visual disturbances, seizures, cardiac arrest.
Treatment: Supportive care; activated charcoal if early; manage seizures and cardiac arrhythmias as per protocols.
Storage and Handling
Storage: Store in a tightly closed container at room temperature (20-25°C), away from moisture and light.
Stability: Stable under proper storage conditions.