Halofantrine is a drug used to treat malaria

Malaria

Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

. Halofantrine's structure contains a substituted phenanthrene

Phenanthrene

Phenanthrene is a polycyclic aromatic hydrocarbon composed of three fused benzene rings. The name phenanthrene is a composite of phenyl and anthracene. In its pure form, it is found in cigarette smoke and is a known irritant, photosensitizing skin to light...

, and is related to the antimalarial drug

Antimalarial drug

Antimalarial medications, also known as antimalarials, are designed to prevent or cure malaria. Such drugs may be used for some or all of the following:* Treatment of malaria in individuals with suspected or confirmed infection...

s quinine

Quinine

Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...

 and lumefantrine

Lumefantrine

Lumefantrine is an antimalarial drug. It is only used in combination with artemether. The term "co-artemether" is sometimes used to describe this combination....

. Marketed as Halfan, halofantrine is never used to prevent malaria and its mode of action is unknown. A crystallographic study have shown that halofantrine binds to hematin in vitro, suggesting a possible mechanism of action. Alternatively or in addition, halofantrine has been shown to bind to plasmpesin, a haemoglobin degrading enzyme unique to the malarial parasites.

Adverse reactions

Halofantrine can cause abdominal pain, diarrhoea, vomiting, rash, headache, itching and elevated liver enzymes.

It can be associated with cardiotoxicity

Cardiotoxicity

Cardiotoxicity is the occurrence of heart electrophysiology dysfunction or/and muscle damage. The heart becomes weaker and is not as efficient in pumping and therefore circulating blood...

. The most dangerous side effect is cardiac arrhythmias: halofantrine causes significant QT prolongation, and this effect is seen even at standard doses. The drug should therefore not be given to patients with cardiac conduction defects and should not be combined with mefloquine

Mefloquine

Mefloquine hydrochloride is an orally administered medication used in the prevention and treatment of malaria. Mefloquine was developed in the 1970s at the United States Department of Defense's Walter Reed Army Institute of Research as a synthetic analogue of quinine...

. A survey from 2009 suggests that the drug is safe when correctly administered

Pharmacology

The mechanism of action of halofantrine is unknown. The absorption of halofantrine is erratic, but is increased when taken with fatty food. Because of fears of toxicity due to increased halofantrine blood levels, halofantrine should be taken on an empty stomach.

Plasma levels peak at 16 hours and the half-life of the drug is about 4 days.

Uses

Halofantrine is only used to treat malaria. It is not used to prevent malaria (prophylaxis) because of the risk of toxicity and unreliable absorption.

Dosing

• Adult dose: Three doses of 500 mg six hours apart.

Halofantrine should be taken on an empty stomach.

Manufacturing information and availability

• Halfan (GlaxoSmithKline
  GlaxoSmithKline
  GlaxoSmithKline plc is a global pharmaceutical, biologics, vaccines and consumer healthcare company headquartered in London, United Kingdom...
  
  ) is available as 250 mg tablets. A full treatment cost (6 tablets) costs US$
  United States dollar
  The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
  
  1.40 in the developing world. Halofantrine is not available in the UK or U.S.