Aminoalcohols

AMINOALCOHOLS

Halofantrine It is a phenanthrene methanol blood schizontocide having activity comparable to mefloquine with which it exhibits cross resistance. It is effective against P. falciparum resistant to chloroquine and S/P, as well as against P. vivax. It is not active against gametocytes or hepatic stages of the malarial parasite.

Oral absorption of halofantrine is low and erratic. The plasma t½ is 1 day, but that of its active metabolite is 3 days. Side effects are abdominal pain, diarrhoea, itching, rashes and occasional elevation of serum transaminase. Prolongation of QTc interval is seen even at therapeutic doses and few cases of serious ventricular arrhythmia (some fatal) are on record.

It is not approved in India, but in other countries it has been used for multiresistant falciparum malaria when no other effective alternative is available.

Lumefantrine

Pyronaridine

Atovaquone This synthetic naphthaquinone is a rapidly acting erythrocytic schizontocide for P. falciparum and other plasmodia. Pneumocystis jiroveci and Toxoplasma gondii are also susceptible to atovaquone. It collapses plasmodial mitochondrial membranes and interferes with ATP production. Proguanil potentiates its antimalarial action and prevents emergence of resistance. A fixed dose oral combination of the two drugs is used for 3 day treatment of uncomplicated chloroquine-resistant P. falciparum as well as P. vivax malaria in the USA and some other countries, but not in India.

Atovaquone is also approved as a second line drug for opportunistic infections with P. jiroveci and T. gondii in AIDS patients. It produces few side effects—diarrhoea, vomiting, headache, rashes and fever.