Vomiting, poor general health, poor compliance, erratic G.I. absorption due to splanchnic vasculopathy etc. make oral therapy less reliable. Therefore, use only parenteral antimalarials. This also means that oral only antimalarials like Mefloquine and Halofantrine have no place in treating severe falciparum malaria. In all cases of P. falciparum malaria, the antimalarial drugs should be chosen depending on the severity of the illness and the sensitivity pattern in the locality. Changing the drugs or adding the drugs in between is not advisable.
Most antimalarial drugs have a long plasma half-life.
Therefore, adding similar drugs half way through the treatment will only add to the adverse effects and not to the therapeutic benefit. Both sulpha and primaquine can precipitate hemolytic crisis in patients with Glucose 6-phoshate dehydrogenase deficiency. Do not exceed the maximum recommended dose of antimalarial drugs . All antimalarial drugs have a narrow safety range and excess dose may lead to adverse effects. Moreover, larger dose does not offer any superior antimalarial effect.