Chapter 48: Antimalarial, Antiprotozoal & Anthelmintic Drugs

falciparum and P. vivax) and primarily transmitted by the Anopheles mosquito. Malaria treatment targets the asexual life cycle stages within the human host—the liver (exoerythrocytic) phase and the blood (erythrocytic) phase—using drugs like chloroquine, hydroxychloroquine (4-aminoquinolines), and primaquine phosphate (an 8-aminoquinoline, effective in the tissue phase). Because of increasing drug resistance, combination therapies such as atovaquone/proguanil are frequently used. The text then addresses non-malarial protozoal infections, including amoebiasis, giardiasis, and trichomoniasis, and notes that pneumocystosis (Pneumocystis jirovecii), although now classified as a fungal infection, is still treated with historically related antiprotozoals like pentamidine isethionate. The broad-spectrum drug metronidazole is highlighted for its efficacy against protozoa, anaerobic bacteria, and some worms, but requires caution due to its potential for a severe disulfiram-like reaction when combined with alcohol. Finally, the chapter covers helminthic infections, caused by multicellular parasitic worms (cestodes, nematodes, and trematodes). Anthelmintic drugs must be highly specific to the causative worm; examples include praziquantel, which treats flukes and tapeworms by increasing calcium influx, and pyrantel pamoate, which paralyzes intestinal roundworms. Throughout all three drug categories, the nursing process is emphasized, requiring detailed assessment of travel history, screening for key contraindications like liver dysfunction and G6PD deficiency (which can lead to drug-induced hemolytic anemia), and educating patients on strict adherence to the regimen and the importance of taking many oral doses with food to minimize gastrointestinal adverse effects.