Periodic blood smears are required after initiating therapy to monitor disease progression. The most appropriate course of action when percent parasitemia is < 1% on a peripheral blood smear is completion of an oral antimalarial regimen, which may be done as an outpatient, provided that the patient is clinically stable enough for discharge following the completion of IV therapy.
There are several appropriate options. The following regimens and dosages are for adults with uncomplicated infection with P falciparum or unknown species acquired from regions with chloroquine resistance or where resistance is unknown. For all other scenarios, consult the CDC treatment table.
Artemether-lumefantrine (Coartem): two doses (80 mg artemether and 480 mg lumefantrine) daily over 3 days
Atovaquone-proguanil (Malarone): one dose (250 mg atovaquone and 100 mg proguanil) daily for 3 days
Quinine sulfate: one dose (542 mg base/650 mg salt) daily for 3 days
PLUS
Doxycycline: two doses (100 mg) daily for 7 daysMefloquine: One-time 750-mg dose followed by a single 500-mg dose given 6-12 hours later
Of these options, artemether-lumefantrine is preferred, followed by atovaquone-proguanil and quinine sulfate plus doxycycline. Mefloquine may cause neuropsychiatric effects and thus should be used only when other options are not available or tolerated.
Special Considerations
Treatment of malaria caused by P vivax or P ovale requires special consideration. These species can remain dormant in the liver of an infected patient and lead to a relapse of clinical disease if not treated effectively. Primaquine and tafenoquine, a newly approved drug, are the only approved drugs capable of killing these dormant liver stages and preventing relapse. As such, treatment of P vivax or P ovale infections requires the addition of either primaquine or tafenoquine to a therapeutic regimen targeting the parasitic forms infecting red blood cells.
Chloroquine is most frequently the first-line drug used to kill blood-stage parasites of both P vivax and P ovale, though other options may be required for patients with drug resistance or severe clinical presentations. Of note, tafenoquine should be used only when added to a regimen of chloroquine; thus, patients requiring a drug other than chloroquine (including those requiring IV artesunate for severe presentations) should receive primaquine to prevent relapse.
Both primaquine and tafenoquine are capable of causing hemolytic anemia in individuals with abnormal glucose-6-phosphate dehydrogenase (G6PD) activity. As such, G6PD activity must be measured with a quantitative G6PD test and confirmed to be within acceptable limits before prescribing primaquine or tafenoquine.
Prevention
The patient returns for follow-up with no complaints after completing his oral regimen. He asks what he can do to prevent this from happening again the next time he visits family in Nigeria.
Public Information from the CDC and Medscape
Cite this: A Man With Fever, Fatigue, and a Trip to Nigeria - Medscape - Mar 04, 2021.
