Rectal artemisinins for malaria: a review of efficacy and safety from individual patient data in clinical studies.
BACKGROUND
Rectal administration of artemisinin derivatives has potential for early treatment for severe malaria in remote settings where injectable antimalarial therapy may not be feasible. Preparations available include artesunate, artemisinin, artemether and dihydroartemisinin. However each may have different pharmacokinetic properties and more information is needed to determine optimal dose and comparative efficacy with each another and with conventional parenteral treatments for severe malaria.


METHODS
Individual patient data from 1167 patients in 15 clinical trials of rectal artemisinin derivative therapy (artesunate, artemisinin and artemether) were pooled in order to compare the rapidity of clearance of Plasmodium falciparum parasitaemia and the incidence of reported adverse events with each treatment. Data from patients who received comparator treatment (parenteral artemisinin derivative or quinine) were also included. Primary endpoints included percentage reductions in parasitaemia at 12 and 24 hours. A parasite reduction of >90% at 24 hours was defined as parasitological success.


RESULTS
Artemisinin and artesunate treatment cleared parasites more rapidly than parenteral quinine during the first 24 hours of treatment. A single higher dose of rectal artesunate treatment was five times more likely to achieve >90% parasite reductions at 24 hours than were multiple lower doses of rectal artesunate, or a single lower dose administration of rectal artemether.


CONCLUSIONS
Artemisinin and artesunate suppositories rapidly eliminate parasites and appear to be safe. There are less data on artemether and dihydroartemisinin suppositories. The more rapid parasite clearance of single high-dose regimens suggests that achieving immediate high drug concentrations may be the optimal strategy.
Gomes
Melba
M
UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, 20 Avenue Appia, Geneva 27, Switzerland. gomesm@who.int
Ribeiro
Isabela
I
Warsame
Marian
M
Karunajeewa
Harin
H
Petzold
Max
M
D000285:Administration, Rectal; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000962:Antimalarials / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use*; D037621:Artemisinins / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008288:Malaria / Q000188:drug therapy*; D008875:Middle Aged; D018512:Parasitemia / Q000188:drug therapy; D010963:Plasmodium falciparum
D000962:Antimalarials; D037621:Artemisinins