Antiparasitics are a class of

medications Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, treat, or preventive medicine, prevent disease. Drug therapy (pharmaco ...

which are indicated for the treatment of parasitic diseases, such as those caused by helminths, amoeba, ectoparasites, parasitic fungi, and protozoa, among others. Antiparasitics target the parasitic agents of the infections by destroying them or inhibiting their growth; they are usually effective against a limited number of parasites within a particular class. Antiparasitics are one of the antimicrobial

drug A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...

s which include

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

that target

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

, and antifungals that target

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

. They may be administered orally, intravenously or topically. Overuse or misuse of antiparasitics can lead to the development of

antimicrobial resistance Antimicrobial resistance (AMR or AR) occurs when microbes evolve mechanisms that protect them from antimicrobials, which are drugs used to treat infections. This resistance affects all classes of microbes, including bacteria (antibiotic resista ...

. Broad-spectrum antiparasitics, analogous to broad-spectrum antibiotics for bacteria, are antiparasitic drugs with efficacy in treating a wide range of parasitic infections caused by parasites from different classes.

Types

Broad-spectrum

Nitazoxanide Nitazoxanide, sold under the brand name Alinia among others, is a broad-spectrum antiparasitic and broad-spectrum antiviral medication that is used in medicine for the treatment of various helminthic, protozoal, and viral infections. It is ...

Antiprotozoals

* Melarsoprol (for treatment of sleeping sickness caused by '' Trypanosoma brucei'') * Eflornithine (for sleeping sickness) *

Metronidazole Metronidazole, sold under the brand name Flagyl and Metrogyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vagino ...

(for vaginitis caused by Trichomonas) * Tinidazole (for intestinal infections caused by '' Giardia lamblia'') * Miltefosine (for the treatment of visceral and cutaneous

leishmaniasis Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus ''Leishmania''. It is generally spread through the bite of Phlebotominae, phlebotomine Sandfly, sandflies, ''Phlebotomus'' an ...

, currently undergoing investigation for Chagas disease)

Antihelminthic

Antinematodes

* Mebendazole (for most nematode infections) * Pyrantel pamoate (for most nematode infections) *

Thiabendazole Tiabendazole (International Nonproprietary Name, INN, British Approved Name, BAN), also known as thiabendazole (Australian Approved Name, AAN, United States Adopted Name, USAN) or TBZ and the trade names Mintezol, Tresaderm, and Arbotect, is a pr ...

(for roundworm infections) * Diethylcarbamazine (for treatment of Lymphatic filariasis) * Ivermectin (for prevention of river blindness) *

Fenbendazole Fenbendazole is a broad-spectrum benzimidazole anthelmintic used against gastrointestinal parasites including: roundworms, hookworms, whipworms, the tapeworm genus '' Taenia'' (but not effective against '' Dipylidium caninum'', a common dog ...

Anticestodes

* Niclosamide (for tapeworm infections) * Praziquantel (for tapeworm infections) * Albendazole (broad spectrum)

Antitrematodes

* Praziquantel

Antiamoebics

* Rifampin * Amphotericin B

Antifungals

* Fumagillin (for microsporidiosis)

Medical uses

Antiparasitics treat parasitic diseases, which impact an estimated 2 billion people.

Administration

Antiparastics may be given via a variety of routes depending on the specific medication, including oral, topical, and intravenous. Resistance to antiparasitics has been a growing concern, especially in veterinary medicine. The Egg hatch assay can be used to determine whether a parasite causing an infection has become resistant to standard drug treatments.

Drug development history

Early antiparasitics were ineffective, frequently toxic to patients, and difficult to administer due to the difficulty in distinguishing between the host and the parasite. Between 1975 and 1999 only 13 of 1,300 new drugs were antiparasitics, which raised concerns that insufficient incentives existed to drive development of new treatments for diseases that disproportionately target low-income countries. This led to new public sector and public-private partnerships (PPPs), including investment by the Bill and Melinda Gates Foundation. Between 2000 and 2005, twenty new antiparasitic agents were developed or in development. Metal-containing compounds are the subject of another avenue of approach.

Research

In the last decades, triazolopyrimidines and their metal complexes have been looked at as an alternative drug to the existing commercial antimonials, searching for a decrease in side effects and the development of parasite drug resistance.

References

{{Authority control Biocides