Which drug is the treatment of choice for severe malaria?
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Clinical Pharmacology · Antifungal and Antiparasitic Medications
Antimalarial Medications
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Malaria drugs are chosen by where the parasite is hiding: blood, liver, or a dormant liver reservoir. Artemisinin combination therapy is first-line for uncomplicated falciparum malaria, and IV artesunate is the treatment of choice for severe disease. Chloroquine has faded due to resistance but survives in rheumatology; primaquine and tafenoquine clear dormant liver forms but require G6PD testing first, since they can trigger dangerous hemolysis. For travelers, fever after visiting a malarious region is malaria until proven otherwise, a true emergency.
The college version
Life Cycle Drives Drug Choice
A mosquito injects sporozoites, which mature silently in the liver (liver stage) before rupturing into the bloodstream to invade red blood cells (blood stage), where replication causes the classic fever pattern. P. vivax and P. ovale can also form hypnozoites, dormant liver forms persisting for months or years and causing relapse long after the original infection seemed resolved. Since drugs act on different stages, treatment must match parasite location: blood-stage drugs treat active illness, but only liver-stage-active drugs achieve radical cure.
ACT and Severe Disease
Artemisinin derivatives kill blood-stage parasites fast but act briefly, so they are paired with a longer-acting partner drug to prevent recrudescence and resistance; this pairing, ACT, is first-line for uncomplicated falciparum malaria. For severe malaria (impaired consciousness, severe anemia, organ dysfunction), IV artesunate is the treatment of choice, having replaced quinine because it lowers mortality and is easier to administer.
Chloroquine and Hydroxychloroquine
Once the backbone of malaria therapy, chloroquine's usefulness has eroded with widespread resistance, especially in falciparum malaria, though it can still suit susceptible strains regionally. Hydroxychloroquine shares its structure and is now used more for autoimmune disease, such as lupus and rheumatoid arthritis, than for malaria. Both carry a risk of irreversible retinal toxicity with long-term use, requiring periodic eye screening, and both can prolong the QT interval, a concern with cardiac risk factors or other QT-prolonging drugs.
Prophylaxis for Travelers
No single drug fits every traveler; choice depends on destination resistance, trip length, and patient factors. Atovaquone-proguanil is well tolerated with a short lead-in and follow-through period. Doxycycline is inexpensive but causes photosensitivity and is unsuitable in pregnancy and young children. Mefloquine suits long trips but carries neuropsychiatric risk, including vivid dreams and anxiety, and rarely more severe disturbance, so it is avoided with a history of psychiatric or seizure disorders.
Radical Cure
Because vivax and ovale malaria can relapse from hypnozoites, curing them requires an added liver-stage-active drug, primaquine or the newer, longer-acting tafenoquine, known as radical cure. Both cause dose-related oxidative hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked enzyme deficiency common across Africa, Asia, and the Mediterranean; hemolysis can be severe and life-threatening, so G6PD testing is an absolute prerequisite.
Quinine and Quinidine
These older cinchona alkaloids were once central to treatment and remain available where newer agents are not, but use is limited by cinchonism: tinnitus, headache, visual disturbance, and gastrointestinal upset, plus cardiac conduction effects requiring monitoring.
Pre-Travel Counseling and the Returned Traveler
A pre-travel visit matches the prophylactic regimen to itinerary and person, stressing two equally important pillars: strict adherence before, during, and after the trip, since liver-stage parasites may still be developing when the traveler returns; and consistent bite prevention (repellents, protective clothing, treated bed nets), since no drug is fully protective. Any fever during or after travel to an endemic area must be treated as malaria until proven otherwise through prompt testing, because delayed diagnosis of falciparum malaria can progress rapidly to severe, life-threatening disease.
Eli explains
The same idea, in plain words
Explain it like I’m 10
Imagine the malaria parasite is a burglar sneaking in through a window (a mosquito bite). First he hides in the attic (the liver) copying himself, then creeps into the living room (the blood) and starts making you sick. Some burglars leave a hidden twin sleeping in the attic that can wake up months later and start the break-in again — that's what vivax and ovale hypnozoites do. Fast medicines clear the living room quickly, but only special attic-clearing medicines get the sleeping twin, and before using those, doctors check a blood test first, since some people's blood cells react badly to them. If you've traveled somewhere with malaria and come home with a fever, you go to the doctor right away, no waiting.
Check yourself
2 review questions from the chapter. Try each one, then open the answer.
A patient who took chloroquine for years for lupus reports new night vision trouble and blurred peripheral vision. What should be suspected, and what happens next?
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Retinal toxicity should be suspected, and the patient needs urgent ophthalmologic evaluation.
Long-term chloroquine or hydroxychloroquine use can quietly damage the retina, and vision changes are a red flag needing an eye specialist right away, since the damage can become permanent if not caught early.
A traveler returns from a malaria-endemic region and develops fever two weeks later. What is the essential first step, and why does timing matter?
Show answer
Treat the fever as malaria until proven otherwise and pursue immediate testing and evaluation.
Because falciparum malaria can turn severe within a short time, delay in diagnosis is dangerous, so returned travelers with fever need prompt testing and treatment rather than a wait-and-see approach.
Quick check
3 questions here. Answers stay hidden until you check.
Why must G6PD testing happen before giving primaquine or tafenoquine?
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Which prophylactic antimalarial is most associated with photosensitivity?
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