Chemoprophylaxis & Treatment - Malaria

CHEMOPROPHYLAXIS & TREATMENT

When patients are counseled on the prevention of malaria, it is imperative to emphasize measures to prevent mosquito bites (eg, with insect repellents, insecticides, and bed nets), because parasites are increasingly resistant to multiple drugs and no chemoprophy-lactic regimen is fully protective. Current recommendations from the Centers for Disease Control and Prevention (CDC) include the use of chloroquine for chemoprophylaxis in the few areas infested by only chloroquine-sensitive malaria parasites (princi-pally the Caribbean and Central America west of the Panama Canal), mefloquine or Malarone^∗ for most other malarious areas, and doxycycline for areas with a very high prevalence of multidrug-resistant falciparum malaria (principally border areas of Thailand) (Table 52–2). CDC recommendations should be checked regularly (Phone: 770-488-7788; Internet: http://www.cdc.gov/malaria), because these may change in response to changing resistance patterns and increasing experience with new drugs. In some circumstances, it may be appropriate for travelers to carry supplies of drugs with them in case they develop a febrile illness when medical attention is unavailable. Regimens for self-treatment include new artemisinin-based combination therapies ,which are widely available internationally (and, in the case of Coartem^∗∗, in the USA); Malarone; mefloquine; and quinine. Most authorities do not recommend routine terminal chemopro-phylaxis with primaquine to eradicate dormant hepatic stages of P vivax and P ovale after travel, but this may be appropriate insome circumstances, especially for travelers with major exposure to these parasites.

Multiple drugs are available for the treatment of malaria that presents in the USA (Table 52–3). Most nonfalciparum infections and falciparum malaria from areas without known resistance should be treated with chloroquine. For vivax malaria from areas with suspected chloroquine resistance, including Indonesia and Papua New Guinea, other therapies effective against falciparum malaria may be used. Vivax and ovale malaria should subsequently be treated with primaquine to eradicate liver forms. Uncomplicated falciparum malaria from most areas is typically treated with Malarone or oral quinine, but new artemisinin-based combina-tions are increasingly the international standard of care, and one combination, Coartem, is now available in the USA. Other agents that are generally effective against resistant falciparum malaria include mefloquine and halofantrine, both of which have toxicity concerns at treatment dosages. Severe falciparum malaria is treated with intravenous artesunate, quinidine, or quinine (intravenous quinine is not available in the USA).