Drug Guide
Halofantrine Hydrochloride
Classification
Therapeutic: Antimalarial
Pharmacological: Antiprotozoal, erythrocytic schizonticide
FDA Approved Indications
- Treatment of uncomplicated Plasmodium falciparum malaria
Mechanism of Action
Halofantrine inhibits the parasite's ability to synthesize proteins required for its survival, primarily affecting the erythrocytic stage of malaria by disrupting mitochondrial function and interfering with parasite replication.
Dosage and Administration
Adult: Initial dose of 1.2 g orally, followed by 480 mg every 8 hours for 2 doses, then 480 mg daily for 2 days (total treatment over 4 days).
Pediatric: Not established; use with caution and per specialist guidance.
Geriatric: Adjust dose cautiously; consider age-related hepatic and cardiac function.
Renal Impairment: Use with caution; dosage adjustments may be necessary.
Hepatic Impairment: Use with caution; potential for altered metabolism; monitor liver function.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed, crosses the placenta, and is concentrated in tissues.
Metabolism: Primarily hepatic via CYP3A4.
Excretion: Bile and feces; minimal urinary excretion.
Half Life: Approximately 4-5 days.
Contraindications
- History of arrhythmias, especially QT prolongation, or concomitant use of other QT-prolonging drugs.
- Hypersensitivity to halofantrine.
Precautions
- Use with caution in patients with cardiac disease, electrolyte disturbances, or hepatic impairment.
- Monitor cardiac function during therapy.
Adverse Reactions - Common
- Nausea, vomiting, abdominal pain (Common)
- Headache, dizziness (Common)
Adverse Reactions - Serious
- QT prolongation, torsades de pointes (Rare)
- Arrhythmias, cardiac arrest (Rare)
- Hepatotoxicity (Rare)
- Allergic reactions (Uncommon)
Drug-Drug Interactions
- Other QT-prolonging drugs (e.g., quinolones, macrolides, certain antipsychotics)
- CYP3A4 inhibitors or inducers
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Baseline ECG (QT interval), liver function tests, electrolyte levels.
Diagnoses:
- Risk for arrhythmias related to QT prolongation
- Risk for hepatotoxicity
Implementation: Administer with food to enhance absorption. Monitor ECG during therapy.
Evaluation: Assess for improvement in malaria symptoms and monitor for adverse effects.
Patient/Family Teaching
- Report any symptoms of irregular heartbeat or fainting.
- Notify provider if symptoms such as dizziness, nausea, or chest pain occur.
- Adhere strictly to prescribed Dosing schedule.
Special Considerations
Black Box Warnings:
- Potential for QT prolongation and life-threatening arrhythmias.
Genetic Factors: Patients with congenital QT prolongation or familial arrhythmia syndromes are at increased risk.
Lab Test Interference: None significant.
Overdose Management
Signs/Symptoms: Severe cardiac arrhythmias, dizziness, hypotension, nausea.
Treatment: Supportive care; monitor cardiac function; administer activated charcoal if ingestion was recent; correct electrolyte imbalances.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable for 2 years under proper storage conditions.