Antiprotozoal agents is a class of pharmaceuticals used in treatment of protozoan infection

Protozoan infection

Protozoan infections are parasitic diseases organisms formerly classified in the Kingdom Protozoa. They include organisms classified in Amoebozoa, Excavata, and Chromalveolata....

.

Protozoans have little in common with each other (for example, Entamoeba histolytica

Entamoeba histolytica

Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide...

is less closely related to Naegleria fowleri

Naegleria fowleri

Naegleria fowleri is a free-living excavate form of protist typically found in warm bodies of fresh water, such as ponds, lakes, rivers, and hot springs. It is also found in soil, near warm-water discharges of industrial plants, and unchlorinated swimming pools in an amoeboid or temporary...

than it is to Homo sapiens) and so agents effective against one pathogen may not be effective against another. However, metronidazole

Metronidazole

Metronidazole is a nitroimidazole antibiotic medication used particularly for anaerobic bacteria and protozoa. Metronidazole is an antibiotic, amebicide, and antiprotozoal....

 is selective for anaerobic organisms, and so it is effective against many (though not all) of these pathogens.

They can be grouped by mechanism or by organism.

Examples

• Eflornithine
  Eflornithine
  Eflornithine is a drug found to be effective in the treatment of facial hirsutism as well as in African trypanosomiasis...
  
  
• Furazolidone
  Furazolidone
  Furazolidone is a nitrofuran antibacterial. It is marketed by Roberts Laboratories under the brand name Furoxone and by GlaxoSmithKline as Dependal-M.-Uses:It is used to treat diarrhoea and enteritis caused by bacteria or protozoan infections....
  
  
• Melarsoprol
  Melarsoprol
  Melarsoprol is a medicinal drug used in the treatment of human African trypanosomiasis. It is also sold under the trade names “Mel B” and “Melarsen Oxide-BAL.”...
  
  
• Metronidazole
  Metronidazole
  Metronidazole is a nitroimidazole antibiotic medication used particularly for anaerobic bacteria and protozoa. Metronidazole is an antibiotic, amebicide, and antiprotozoal....
  
  
• Ornidazole
  Ornidazole
  Ornidazole is a drug that cures some protozoan infections. It is used by the poultry industry.It has been investigated for use in Crohn's disease after bowel resection.-References:...
  
  
• Paromomycin sulfate
  Paromomycin sulfate
  Paromomycin is an aminoglycoside antibiotic, first isolated from Streptomyces krestomuceticus in the 1950s. It is also called monomycin and aminosidine;-Uses:...
  
  
• Pentamidine
  Pentamidine
  Pentamidine is an antimicrobial medication given for prevention and treatment of Pneumocystis pneumonia caused by Pneumocystis jirovecii , a severe interstitial type of pneumonia often seen in patients with HIV infection...
  
  
• Pyrimethamine
  Pyrimethamine
  Pyrimethamine is a medication used for protozoal infections. It is commonly used as an antimalarial drug , and is also used in the treatment of Toxoplasma gondii infections in immunocompromised patients, such as HIV-positive individuals.-Mechanism of action:Pyrimethamine interferes with...
  
  
• Tinidazole
  Tinidazole
  Tinidazole is an anti-parasitic drug used against protozoan infections. It is widely known throughout Europe and the developing world as treatment for a variety of amoebic and parasitic infections...