Drug-Resistant Malaria - libdoc.who.int - World Health Organization

v.
Recent Research Results Related to the
Chemotherapy of Malaria
MECHANISM OF DRUG RESISTANCE
Among the biological phenomena of the malaria parasite,
resistance to antimalarial drugs is probably the one which is
causing the most important interference with the control of the
disease. It helps the parasite to overcome the challenge posed by
antimalarial drugs. However, knowledge of the biological basis of
drug resistance and of the mode of action and the pharmacokinetics
of antima1aria1s may help to overcome the resourcefulness of the
parasite and through a well-planned tactical deployment of antimalarial
measures, it may be possible to limit the spread and to
eliminate or at least reduce the impact of drug-resistant
P.falciparum in exposed popu1ations and antima1aria programmes.
Antimalarial drugs directed against human-pathogenic
plasmodia show marked stage-specific and often also speciesspecific
action. There are moreover important natural strain
differences in the drug sens1t1v1ty of particular species and
stages, without necessarily implying natural drug resistance in
less susceptible strains. In the case of P. fa1ciparum, a natural
parasite population is composed of individuals showing different
susceptibility to the drug, within a relatively limited range if
the isolate is sensitive, within a wider range if it is resistant.
In order to be effective, a drug has to interfere with one or
several essential life functions, usually metabolic functions, of
the parasite. To do so, the drug has to be available at the place
of action for a long enough time and in an adequate quantity/
concentration to ensure damage to the parasite. Pharmacokinetic