Chloroquine (TEVA-Chloroquine)

Product Information

• Name: TEVA-CHLOROQUINE
• Active Ingredient: Chloroquine Phosphate
• Strength: 250 mg tablets (equivalent to 155 mg chloroquine base)
• Manufacturer: Teva Canada Limited

Therapeutic Classification

• Class: Antimalarial, Antiparasitic

Indications and Clinical Use

• Malaria:
  • Suppressive treatment and curative treatment of acute attacks due to P. vivax, P. malariae, P. ovale, and susceptible strains of P. falciparum.
  • Not effective against chloroquine-resistant strains.
• Extraintestinal Amebiasis: Treatment of amebiasis outside the intestines.

Contraindications

• Presence of retinal or visual field changes attributable to 4-aminoquinoline compounds.
• Known hypersensitivity to chloroquine or related compounds.

Warnings and Precautions

• Chloroquine-Resistant Malaria: Ineffective against resistant strains. Use alternative therapies in such cases.
• Retinopathy: Risk of irreversible retinal damage with long-term or high-dosage use. Regular ophthalmologic examinations recommended.
• Auditory Effects: Risk of nerve type deafness and tinnitus; discontinue if hearing loss occurs.
• Muscular Weakness: Periodic examination for muscular weakness; discontinue if weakness is detected.
• Pediatric Accidental Ingestion: Potentially fatal in small doses. Keep out of reach of children.
• Psoriasis and Porphyria: May precipitate severe attacks; use only if benefits outweigh risks.
• Pregnancy and Lactation: Crosses placenta and is excreted in breast milk; use only if benefits justify risks.
• Hepatic Impairment: Use with caution; may concentrate in the liver.
• Hematologic Effects: Monitor blood counts periodically; use with caution in G6PD deficiency.
• Cardiac Effects: Risk of cardiomyopathy and arrhythmias; monitor cardiac function and discontinue if symptoms develop.

Adverse Effects

• Ocular: Irreversible retinal damage, visual disturbances.
• Neuromuscular: Seizures.
• Auditory: Deafness, tinnitus.
• Gastrointestinal: Anorexia, nausea, vomiting, diarrhea, abdominal cramps.
• Dermatologic: Skin eruptions, pigmentary changes, pruritus, hair loss.
• Central Nervous System: Headache, psychiatric symptoms (anxiety, confusion, hallucinations, depression).
• Cardiovascular: Hypotension, ECG changes, cardiomyopathy, arrhythmias.

Drug Interactions

• Antacids and Kaolin: Reduce absorption of chloroquine; observe 4-hour interval.
• Cimetidine: Inhibits metabolism, increasing plasma levels; avoid concomitant use.
• Antidiabetic Drugs: May enhance hypoglycemic effects; monitor and adjust dosage.
• Arrhythmogenic Drugs: Increased risk of arrhythmias with drugs like amiodarone and moxifloxacin.
• Ampicillin: Reduced bioavailability; observe a 2-hour interval.
• Cyclosporine: May increase serum levels; monitor closely.
• Mefloquine: Increased risk of convulsions.
• Praziquantel: Reduced bioavailability.
• Tamoxifen: Increased risk of retinal toxicity; avoid concomitant use.

Symptoms and Treatment of Overdose

• Symptoms: Headache, drowsiness, visual disturbances, nausea, vomiting, cardiovascular collapse, convulsions, respiratory and cardiac arrest.
• Treatment: Immediate medical attention required; gastric lavage, activated charcoal, symptomatic care, monitoring for at least 6 hours.

Dosage and Administration

Adult Dosage:

• Prevention: 310 mg base once weekly, starting one week before entering a malaria-endemic area, during exposure, and for 4 weeks after leaving.
• Treatment: Loading dose of 620 mg base, followed by 310 mg base at 6, 24, and 48 hours.

Pediatric Dosage:

• Prevention: 5 mg base/kg once weekly, starting one week before entering a malaria-endemic area, during exposure, and for 4 weeks after leaving (specific doses provided in the document).
• Treatment: Loading dose of 10 mg base/kg, followed by 5 mg base/kg at 6, 24, and 48 hours.

Advantage:

• Long-term safety data for prophylaxis.

Disadvantage:

• Most areas now report chloroquine resistance.

Storage

• Store at 15°C to 30°C. Keep out of reach of children.