Therefore severe toxicity, which is due to unbound quinine, is not common in patients with malaria, though the same doses given to a healthy volunteer would be highly toxic. Quinine is well absorbed by intramuscular injection, though it is irritant. Abscesses may form at the sites of injection, though the risk of this is reduced by observing scrupulously sterile technique and by using the anterior thigh rather than the buttock, to avoid injection into fat. Resistance to quinine is increasing in S-E Asia. These compounds are extracts of the Chinese herb Artemisia annua, and are rapidly-acting antimalarial compounds which have now been used in over 1.5 million patients with falciparum malaria.
Artemisinin suppositories are ideal for paediatric use or use in remote areas.
Artemisinin derivatives are active against the early stages of P. Falciparum and reduce the duration of fever and clear parasites faster than other antimalarials. One problem with artemisinin derivatives is that, until recently, none satisfied the requirements of good manufacturing practice in the west. Those that now do, namely artemether and arteether, may not be the most effective and the latter compound is virtually unevaluated in clinical trials. The second problem is that both artmether and arteether, given in high doses and for prolonged periods, have caused brain damage in dogs. The final issue of controversy is availability.