Chloroquine treatment regimen

Knowledge of local resistance patterns is important to determine the treatment regimen. There is increasing chloroquine and pyrimethamine-sulfado-xine (Fansidar) resistance in Africa and in some areas at the border of Thailand there is resistance for almost all antimalarial drugs including halofantrine, mefloquine and quinine. In these areas only the artemisinin derivatives (artemether, arteether, arte-sunate, dihydroartemisinin) are effective. 

Other oral treatment regimens for infections with chloroquine-resistant P. vivax and drug-resistant strains o/P. falciparum... 

When advising potential travelers on prophylaxis for malaria, be aware of the incidence of chloroquine-resistant P. falciparum malaria and the countries where it is prevalent. In patients who have P. vivax or P. ovale malaria (note that some patients can have P. falciparum and one of these species), following the treatment of the acute phase of malaria and screening for glucose-6-phosphate dehydrogenase deficiency, patients should receive a regimen of primaquine for 14 days to ensure eradication of the hypnozoite stage of P. vivax or P. ovale. For detailed recommendations for prevention of malaria go to www.cdc.gov/travel/. 

Sulfonamides, such as sulfadiazine, in combination with pyrimethamine, are considered the treatment of choice of symptomatic toxoplasmosis. Patients should be well hydrated to prevent crystalluria this problem may be reduced with the use of triple sulfas (trisulfapyrimidine). Some regimens have included a sulfonamide (sul-fadoxine) in combination with pyrimethamine (Fansidar) for the treatment of chloroquine-resistant malaria caused by P. falciparum. 

Chloroquine can cause seizures in patients with epilepsy. The mechanism is uncertain, but it may include reductions in inhibitory neurotransmitters and pharmacokinetic interactions that alter anticonvulsant concentrations. Tonic-clonic convulsions were reported in four patients in whom chloroquine was part of a prophylactic regimen. Antiepileptic treatment was required to control the seizures. None had further seizures after withdrawal of the antimalarial drugs (9). 

In P. falciparum (chloroquine-resistant) infections, a dose of 750 mg mefloquine followed by 500 mg 12 hours later is recommended. The pediatric dose of mefloquine is 15 mg/kg (<45 kg) followed by 10 mg/kg 8 to 12 hours later.Intravenous quinidine gluconate followed by oral quinine should be administered for severe illness, as already indicated.A second drug needs to be administered in chloroquine-resistant P. falciparum, and this second drug should follow the oral quinidine regimen either a single dose of three tablets of pyrimethamine-sulfadoxine (Fansidar) on the last day of intravenous quinidine or clindamycin 900 mg three times daily for 3 to 5 days. An alternative oral treatment for chloroquine-resistant P falciparum infection in adults, especially in those with a history of seizures or psychiatric disorders, is the combination of atovaquone 250 mg and proguanil 100 mg (Malarone) (4 tablets daily... 

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