Introduction Drugs pyrimethamine sulfadiazine suramin melarsoprol nifurtimox sodium stibogluconate metronidazole amphotericin B benznidazole nitazoxanide Clinical use protozoa treatment see anti-malarials topic for malaria-specific treatments Anti-Protozoal Medications Drug Mechanism of Action Adverse Effects Indications Pyrimethamine + sulfadiazine Pyrimethamine: folic acid antagonist Sulfadiazine: competitive antagonism with para-aminobenzoic acid (also anti-folate) Gastrointestinal upset Drug rash Pancytopenia Folate deficiency co-administer with leucovorin Toxoplasma gondii Suramin Unknown but inhibits trypanosomal energy metabolism Gastrointestinal upset Peripheral neuropathy Renal toxicity Trypanosoma brucei, blood-borne disease Melarsoprol Inhibits pyruvate kinase Brain dysfunction Renal toxicity Hepatic toxicity Trypanosoma brucei, central nervous system disease Nifurtimox Causes breakdown of DNA via radical metabolite formation Gastrointestinal upset Headache Weight loss Trypanosoma cruzi Sodium stibogluconate Unknown but may inhibit citric acid cycle and glycolysis in the protozoa Loss of appetite Gastrointestinal upset Myalgias Fatigue Pancreatitis Leishmania donovani Metronidazole Causes breakdown of DNA via free radical metabolite formation Disulfiram-like reaction with alcohol Headache Metallic taste Giardia lamblia Entamoeba histolytica Trichomonas vaginalis treat the partner too Amphotericin B Binds ergosterol and allows leakage of electrolytes from the membrane Fevers and chills Hypotension Renal toxicity Arrhythmias Anemia Phlebitis Leishmania donovani Naegleria fowleri Benznidazole Causes breakdown of DNA via free radical metabolite formation Rash Peripheral neuropathy Myalgias Loss of appetite Bone marrow suppression Trypanosoma cruzi Nitazoxanide Disrupts anaerobic energy metabolism Gastrointestinal upset Rash Fever Cryptosporidium