*Antiprotozoal Agents

Chapter: Antiprotozoal Agents
McMaster Section Editor(s): Mark Loeb
Section Editor(s) in Interna Szczeklika: Piotr Zaborowski, Jerzy Stefaniak, Miłosz Parczewski, Weronika Rymer, Agnieszka Wroczyńska
McMaster Author(s): Bahareh Ghadaki, Marek Smieja, Shariq Haider
Author(s) in Interna Szczeklika: Jerzy Stefaniak, Szymon Nowak
Additional Information

1. Antibiotics: Metronidazole, tinidazole, sulfamethoxazole/trimethoprim, clindamycin, spiramycin. For details, please see Antibacterial Agents.

2. Atovaquone:

1) Spectrum of activity: Used as an alternative therapy for prophylaxis or treatment of Pneumocystis jirovecii (formerly carinii) pneumonia in patients who do not tolerate sulfamethoxazole/trimethoprim. It also shows activity against toxoplasmosis and is used in combination therapy with azithromycin for the treatment of babesiosis.

2) Adverse reactions: Hypersensitivity reaction. Gastrointestinal effects, such as vomiting and diarrhea. Use with caution in patients with severe liver impairment as rare cases of cholestatic hepatitis and liver failure have been reported. Methemoglobinemia.

3) Pregnancy risk: C (Table 1 in Antimicrobial Agents).

3. Benznidazole (oral):

1) Spectrum of activity: Primary therapy for American trypanosomiasis (Chagas disease).

2) Adverse reactions: Angioedema. Cutaneous effects (rash, photosensitivity, exfoliative dermatitis, Stevens-Johnson syndrome). Peripheral neuropathy (dose-dependent). Hematologic effects, such as bone marrow suppression. A disulfiram-like reaction can occur with concomitant alcohol use (nausea, vomiting, flushing, headache).

3) Pregnancy risk: Not classified. Avoid in pregnancy.

4. Furazolidone:

1) Spectrum of activity: A nitrofuran derivative. It is used as alternative therapy for the treatment of resistant Giardia lamblia infection and also considered as alternative therapy for Vibrio cholera infection.

2) Adverse reactions: Hypersensitivity reaction. Gastrointestinal effects, such as vomiting and diarrhea. A disulfiram-like reaction can be seen when taken with alcohol.

3) Pregnancy risk: Safety in the childbearing age has not been established.

5. Iodoquinol:

1) Spectrum of activity: Iodoquinol is used predominantly for the treatment of noninvasive Entamoeba histolytica infection, Dientamoeba fragilis infection, and considered an alternative treatment for Balantidium coli infection.

2) Adverse reactions: Hypersensitivity reaction. Because iodoquinol contains iodine, caution should be used in patients with thyroid disease. Prolonged use may result in optic neuritis and peripheral neuropathy.

3) Pregnancy risk: Safety in the childbearing age has not been established.

6. Miltefosine (oral):

1) Spectrum of activity: Miltefosine is indicated for the treatment of visceral and cutaneous leishmaniasis.

2) Adverse reactions: Gastrointestinal adverse effects (nausea, vomiting, and diarrhea). Central nervous system effects include headache and vertigo.

3) Pregnancy risk: D (Table 1 in Antimicrobial Agents).

7. Nitazoxanide:

1) Spectrum of activity: Nitazoxanide is used for the treatment of Cryptosporidium infection. It also has activity against E histolytica and G lamblia.

2) Adverse reactions: Hypersensitivity reaction. Gastrointestinal effects, such as abdominal pain, vomiting, and diarrhea.

3) Pregnancy risk: B (Table 1 in Antimicrobial Agents).

8. Nifurtimox (oral):

1) Spectrum of activity: Primary therapy for American trypanosomiasis (Chagas disease).

2) Adverse reactions: Gastrointestinal adverse effects are common and include abdominal pain, nausea, vomiting, and diarrhea. Central nervous system effects are also common and include insomnia, irritability, depression, tremors, and peripheral neuropathy. Cutaneous effects (erythema, pruritus). Avoid alcohol use during treatment as it may increase the risk of adverse effects.

3) Pregnancy risk: Not classified. Avoid use in pregnancy.

9. Paromomycin (oral, topical):

1) Spectrum of activity: Paromomycin is an aminoglycoside antibiotic showing no gastrointestinal absorption. It is used in the treatment of noninvasive E histolytica and to eliminate luminal cysts after treatment of invasive disease. It also has activity against D fragilis, Cryptosporidium parvum, and G lamblia. As topical therapy, it has been used for the treatment of cutaneous leishmaniasis.

2) Adverse reactions: Hypersensitivity reaction. Gastrointestinal effects, such as abdominal pain, vomiting, and diarrhea.

3) Pregnancy risk: B (Table 1 in Antimicrobial Agents).

10. Pentamidine (IV, inhaled):

1) Spectrum of activity: Inhaled and parenteral pentamidine is used for prophylaxis and treatment of P jirovecii pneumonia. It is also active against Leishmania spp, Trypanosoma brucei gambiense (West African sleeping sickness), and free-living amoebas (Acanthamoeba and Balamuthia).

2) Adverse reactions: Hypersensitivity reaction. Because pentamidine may cause QT prolongation, avoid it in patients with underlying risk factors for prolonged QT; other cardiac effects include hypotension and arrhythmias. Reversible nephrotoxicity and electrolyte abnormalities, including hyponatremia, hyperkalemia, hypomagnesemia, and hypocalcemia. Hematologic effects (neutropenia, thrombocytopenia). Pentamidine can be toxic to pancreatic islet beta cells, causing hypoglycemia and pancreatitis.

3) Pregnancy risk: C (Table 1 in Antimicrobial Agents).

11. Pentavalent antimonials: Sodium stibogluconate (IV, IM) and meglumine antimoniate (IV, IM):

1) Spectrum of activity: These agents are indicated for the treatment of visceral and cutaneous leishmaniasis.

2) Adverse reactions: Gastrointestinal effects, such as nausea and vomiting, hepatitis, and pancreatitis. Arthralgias and myalgias. Cardiotoxicity including QT prolongation. Bone marrow suppression.

3) Pregnancy risk: Not classified.

12. Pyrimethamine:

1) Spectrum of activity: Pyrimethamine in combination therapy is used for the treatment of toxoplasmosis (pyrimethamine/sulfadiazine) and prophylaxis of Pneumocystis pneumonia (pyrimethamine/dapsone). It also has activity against Cystoisospora belli.

2) Adverse reactions: Hypersensitivity reaction. Hematologic effects, such as hemolytic anemia (especially in patients with glucose-6-phosphate dehydrogenase deficiency), megaloblastic anemia (in those with folate deficiency), neutropenia, and thrombocytopenia. In patients receiving high doses of pyrimethamine, administer concomitant folinic acid.

3) Pregnancy risk: C (Table 1 in Antimicrobial Agents).

13. Antifungal agents: Fluconazole and amphotericin B. For details, please see Antifungal Agents.

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