Indications/Uses
Malaria.
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Dosage/Direction for Use
Adult : PO 500 mg 6 hrly for 3 doses. May repeat a wk later in patients w/ little or no previous exposure to malaria.
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Dosage Details
Oral
Malaria Adult: 3 doses of 500 mg at intervals of 6 hr, repeat a wk later in patients with little or no previous exposure to malaria.
Child: >37 kg: 3 doses of 500 mg at intervals of 6 hr; 32-37 kg: 3 doses of 375 mg at intervals of 6 hr; 23-31 kg: 3 doses of 250 mg at intervals of 6 hr. Course may be repeated a wk later in patients with little or no previous exposure to malaria. |
Contraindications
Existing or family history of prolonged QT-interval; cardiac disease; unexplained syncopal attacks; thiamine deficiency; electrolyte disturbances or taking arrhythmogenic drugs; previous or concurrent treatment with mefloquine; hypersensitivity; pregnancy; lactation.
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Special Precautions
Chronic liver disease; baseline EKG should be performed; haematocrit and Hb level must be monitored closely. Fatty food should be avoided for 24 hr after admin of halofantrine to prevent increase in bioavailability and thus risk of toxicity. Cardiac rhythm should be monitored during and for 8-12 hr after completion of treatment.
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Adverse Reactions
Diarrhoea, abdominal pain, nausea, vomiting, pruritis, skin rash; hypersensitivity reactions; intravascular haemolysis.
Potentially Fatal: Serious ventricular arrhythmias. |
Overdosage
Symptoms include GI distress and palpitations. In cases of overdosage, induce vomiting with appropriate supportive measures including ECG monitoring.
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Drug Interactions
Drugs that cause electrolyte disturbances e.g. diuretics. Mefloquine; drugs that induce arrhythmia eg, chloroquine, quinine, TCAs; some antiarrhythmics (amiodarone, dysopyramide, flecainide, procainamide, quinidine and sotalol), cisapride, astemizole and terfenadine.
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Food Interaction
Food increases bioavailability and toxicity.
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Lab Interference
Interfere with liver function tests and bilirubin levels (increase results).
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Action
Description: Halofantrine, a 9-phenanthrenemethanol, is a blood schizontocide that is active against chloroquine-resistant falciparum and vivax malaria. It can destroy asexual blood forms and inhibit proton pump.
Pharmacokinetics: Absorption: Oral admin: Absorption is slow and erratic; peak levels occur in 3-7 hr. Bioavailability is increased when given with or after food, especially food high in fat content. Metabolism: Metabolised hepatically. Main metabolite (desbutylhalofantrine) appears as active as the parent compound. Excretion: Mainly via faeces. Elimination half-life varies between individuals but generally about 1-2 days. |
Storage
Store at 20-25°C.
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MIMS Class
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