Pyronaridine is a blood schizontocidal drug that is structurally related to chloroquine, being a substituted 1-aza-acridine and also a substituted 1,5-napthyridine. It has been shown to have a high in vitro activity against chloroquine sensitive and chloroquine resistant strains of Plasmodium falciparum and this high activity has been validated in clinical trials in China, Thailand and Cameroon, in which malarias resistant to chloroquine were cured.
Pyronaridine is a promising drug and there are plans to release it for clinical use in Africa in the coming years, but its mechanism of action is not yet understood. It has more gastrointestinal side-effects than chloroquine. There are insufficient data at present to recommend the use of pyronaridine for the treatment of malaria in non-immune travellers.
Pyronaridine was first synthesized in China in 1970. It belongs to the same class of drugs as chloroquine and is effective against chloroquine-resistant parasites. Extensive experience has been gained in the use of pyronaridine alone (not in combination) for malaria in Hunan and Yunan Provinces, China, where it has been found to be safe and effective. The addition of artesunate will provide faster onset of actions and should delay the development of resistance. This combination will be assessed for safety and efficacy in the treatment of uncomplicated acute P. falciparum (and possibly vivax) malaria in adults and children in South-East Asia and Africa.