To define the frequency of the early rising of parasitemia in falciparum malaria
patients treated with artemisinin derivatives, a retrospective chart review of
497 patients admitted to the Hospital for Tropical Diseases, Bangkok in 1996 was
carried out. Early rising parasitemia, defined as an increase in the parasite
count over the baseline pretreatment level during the first 24 hours of
treatment, was found in 59/229 episodes (25.8%) of uncomplicated, and 111/268
episodes (41.3%) of complicated falciparum malaria. All uncomplicated cases were
successfully treated without developing any complications. There were 2 deaths
and 13 changes of drug regimen in the complicated group. Only one of these
unfavorable responses was due to parasite response. Early rising parasitemia was
very common in falciparum malaria treated with artemisinin derivatives, despite
their ability to clear the parasitemia, and did not indicate failure of the drug used.