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• Pharmacology and mechanism of action

  Halofantrine is a phenanthrenemethanol antimalarial drug developed by the US military. The antimalarial activity of the phenanthrenemethanols was discovered during the Second World War but was not exploited until later. Halofantrine is a potent blood schizontocide against Plasmodium falciparum both in vitro and in vivo. However, it has no effect against exoerythrocytic forms of the parasite. Experience of its activity against other malaria species is limited. The drug exists as a racemic mixture, but the two enantiomers have shown similar activity in vitro ^{[1, 2]}.
  The mechanism of action of halofantrine is not known. ;

• Indications

  Halofantrine is indicated only for the treatment of multidrug-resistant Plasmodium falciparum malaria. ;

• Side effects

  Halofantrine is generally well tolerated. Mild and transient side effects such as nausea, vomiting, diarrhoea, abdominal pain, pruritus and rash have been reported in humans. Halofantrine is potentially cardiotoxic particularly with doses above the recommended dose and causes ECG changes such as prolongation of PR and QTc intervals. In one study, the sudden death of a patient was reported after receiving a high dose of halofantrine (8 mg/kg 3 times daily for 3 days) ^[3]. The patient had previously been treated with mefloquine. Cardiotoxicity due to halofantrine will become a therapeutic problem if higher dosage regimens have to be used due to decreased efficacy ^[3]. Occasional elevation of serum transaminase have been observed in some patients. The relationship of this to the treatment is unclear. Values usually return to normal levels within a week after treatment ^[4-6]. ;

• Contraindications and precautions

  Halofantrine should not be given to patients with pre-existing cardiovascular diseases. There is a warning against the concomitant intake of any cardiotoxic drugs. Halofantrine is not used for malaria prophylaxis. ;

• Interactions

  There are no reports of interactions ^[7]. ;

• Preparations

  Available as halofantrine hydrochloride: 100 mg hydrochloride is equal to 93 mg base. Not yet available for parenteral use.
  • Halfan® (SmithKline & Beecham). Tablets 250 mg. Oral suspension 20 mg/ml. ;

• References

  1. Bryson HM, Goa KL (1992). Halofantrine. A review of its antimalarial activity, pharmacokinetic properties and therapeutic potential. Drugs, 43, 236–258.
  2. Karle JM, Olmeda R, Gerena L, Milhous WK (1994). Plasmodium falciparum: Role of absolute stereochemistry in the antimalarial activity of synthetic aminoalcohol antimalarial agents. Exp Parasitol, 76, 345–351.
  3. Nosten F, ter Kuile FO, Luxemburger C, Woodrow C, Kyle DPE, Chongsuphajaisiddhi T, White NJ (1993). Cardiac effects of antimalarial treatment with halofantrine. Lancet, 341, 1054–1056.
  4. Watkins WM, Lury JD, Kariuki D, Koech DK, Oloo JA, Mosoba M, Mjomba M, Gilles HM (1988). Efficacy of multiple-dose halofantrine in treatment of chloroquine-resistant falciparum malaria in children in Kenya. Lancet, 2, 247–250.
  5. Salako LA, Sowunmi A, Walker O (1990). Evaluation of the Clinical trials and safety of halofantrine in falciparum malaria in Ibadan Nigeria. Trans R Soc Trop Med Hyg, 84, 644–647.
  6. Boudreau EF, Pang LW, Dixon KE, Webster HK, Pavanand K, Tosingha L, Somutsakorn P, Canfield CJ (1988). Malaria: Treatment efficacy of halofantrine (WR171,669) in initial field trials in
  7. Karbwang J, Na Bangchang K (1994). Clinical pharmacokinetics of halofantrine. Clin Pharmacokinet, 27(2), 104–119. ;

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