Dr. Murai Éva szerk.: Parasitologia Hungarica 26. (Budapest, 1993)
Parasit, hung., 26: 5-10, 1993 © Hungarian Society of Parasitologists Treatment of chloroquine-resistant Plasmodium falciparum malaria by a combination of quinine and quinidine Ágnes AXMANN 1 and Trinh K. ANH 2 l Clinic of Infectious and Tropical Diseases, „Imre Haynal" University of Medical Sciences, Budapest, Szabolcs u. 35, Hungary; 2 Institute of Malariology, Hospital Cho Ray, Ho Chi Minh City, Vietnam (Received 12 September, 1993) Abstract: The increasing number of chloroquine-resistantWasmo^ii^/a/cipumm (Pf.) malaria cases made it necessary to look for a new therapeutic agent effective against this life-threatening disease. The excellent antimalarial effect of quinidine proven in vitro by several authors from Thailand gave us the idea to use it for an in vivo study. The aim of this study was to find the ideal dose of quinidine for malaria treatment, to avoid or diminish its effects on the heart while keeping its antimalarial efficacy. The solution was found in a combination of quinidine with his stereoisomer quinine, where the synergy of the parent compounds allowed a dose reduction of quinidine while keeping its antimalarial effects. Key words: Plasmodium falciparum malaria, chloroquine resistance, treatment, quinine, quinidine INTRODUCTION An escalating problem in the treatment of malaria in the last 20-25 years has been the emergence in many parts of the world of malarial parasites resistant to several antimalarial drugs of different structure (Danis and Duflo 1988, Jacobs et al. 1988, Kremsner et al. 1988, Krogstad et al. 1988, White 1988). One typical region having this problem is South-East Asia (Bunnag el al. 1987, Harinasuta et al. 1983). The resistance of P.f to chloroquine in vitro is very high in South Vietnam where all three types of resistance (RI, RII and RIII) occur in vivo. The minimum inhibitory concentration (MIC) of quinidine is two to four times lower than that of quinidine (Bunnag and Harinasuta 1987) and in vivo data collected by the authors showed that the parasite's clearance time of quinidine is shorter than that of quinine (Axmann et al. 1989). This means that quinidine seems to be a good alternative therapeutic agent in drug-resistant P.f. malaria. When quinidine alone is used as antimalarial agent at a
