Pharmacokinetics and pharmacodynamics of qinghaosu derivatives: how do they impact on the choice of drug and the dosage regimens?
The critical decisions of which artemisinin derivative(s) to use and by which route(s) of administration for falciparum malaria are complex scientifically and politically. Despite the need for additional pharmacokinetic, pharmacodynamic and toxicokinetic data, these drugs are too important to delay concise, rational recommendations any longer. These types of decisions must be made now, implemented on a multinational level with WHO leadership, and revised as new findings emerge. For acute, uncomplicated disease, per os dosing of artesunate or artemether for three days is recommended, but only in combination with other antimalarial drugs like mefloquine. For severe falciparum malaria, intravenous administration is the preferred route, yet current formulations for intravenous dosing are not optimal and should be an area for future development emphasis. Clearly intramuscular administration of artemether has proven effective for severe disease, yet dosing regimens shouldn't be designed with ultimate parasitological cure as the aim and the problem of bioavailability of the sesame oil formulations must be examined further. Once the life-saving reduction in parasitemia and pathophysiological sequelae have been achieved, the patient can be given oral medication to affect radical cure. Much more data will be required to define the role of per rectum dosing for the treatment of severe malaria, yet this approach holds great promise as a life-saving intervention in rural areas where this disease has it most dramatic impact.
Kyle
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Department of Parasitology, Walter Reed Army Institute of Research, Washington DC, USA. kyled@wrsmtp-ccmail.army.mil
Teja-Isavadharm
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Li
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Leo
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D000284:Administration, Oral; D000285:Administration, Rectal; D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use*; D037621:Artemisinins; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical; D003657:Decision Making; D016903:Drug Monitoring; D006801:Humans; D007262:Infusions, Intravenous; D007273:Injections, Intramuscular; D016778:Malaria, Falciparum / Q000188:drug therapy*; D051379:Mice; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D051381:Rats; D012717:Sesquiterpenes / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use*
D000962:Antimalarials; D037621:Artemisinins; D012717:Sesquiterpenes; C031327:artemisinin