About Antiparasitics


Antiparasitics are antimicrobial medicines used for to treat infections and diseases caused by parasites. It is estimated that 2 billion people are affected by various forms of diseases caused by parasites. A parasite can be defined as an organism that lives on or in and relies on another organisms, known as host for nutrients and survival. Parasites include protozoa, helminths, parasitic fungi, amoeba and protozoa, among others.

Antiparasitics are designed to either inhibit the growth of the parasitic agents or destroy them as a measure of protecting the host against diseases they transmit. They are available in different forms and can be administered topically, intravenously or orally. There are many classes of parasites. To fight them, antiprasitics are formulated to target different classes of parasites or specific parasites.


The early developments of anti-parasitic medications had a number of challenged. They were not effective, had high levels of toxicities and difficult to administer due to challenges of establishing the difference between the parasite and the host. As at the late 1990, only a paltry 13 new drugs were antiparasitics against a total of 1, 3000 total drugs in the world. Public private partnership initiatives with the backing of the Bill and Melinda Gates Foundation saw the development of about 20 new antiparasitics.

However, the costs were still high ($300 million for an antimalarial) but with a high failure rate of about 50%. Today, with more partnerships, research and innovation, there are different antiparasitics for specific classes of parasites. These medicines are readily available with or without prescription.

Types of Antiparasitics

1. Broad-Spectrum: These are antiparasitics that have been developed to treat a wide array of infections caused by wide range of parasites from various classes. They are effective in multi-parasite infections and are highly recommended for treatment of diseases such as malaria. They include Nitazoxinade.

2. Antiprotozoals: The complex nature of protozoans makes it difficult to treat protozoal infections, considering their varied phylogenetic groups. To guarantee effectiveness in treatment, they have been grouped based on the organisms or mechanisms. Some recent studies propose using viruses to treat protozoal infections. Common antiprotozoals include:

  • Metronidazole - a drug is used for the treatment of vaginitis that is usually caused by trichomonas.
  • Melarsoprol - a drug is common in treatment of diseases such as sleeping sickness that is caused by the Typanosoma brucei parasite. Their mechanisms closely resemble that of Eflorithine.
  • Tinidazole - a drug treats infections in the intestines that are caused by the Giardia lamblia.
  • Miltefosine - a drug is prescribed for the treatment of leishmaniasis.

3. Anthelminthics: They are used to treat infections caused by helminths or parasitic worms, both flat worms like tapeworms and flukes and round worms such as nematodes. Parasitic worms do not only affect humans, but also livestock and plants. They work by either killing or stunning the worms out of the bodies of the hosts without causing serious damage to the host. There are different classes of anthelminthic drugs: antinematodes, anticestodes and antitrematodes.

4. Antiamoebics: They are used to treat infections caused by amoeba such as amoebiasis, also known as amoebic dysentery that is caused by Entamoeba histolytica. Some common antimoebics include Rifampin and Amphotericin.

Qualities of Good Antiparasitics

Early developments of antiparastics were found to be equally harmful to the host as the parasites they were being used to eliminate. Their administration was also a challenge and they were not as effective as expected. With advanced screening methods, it is now easier to clearly identify active compounds that should be targeted with low toxicity levels. Treatment is based on biochemical knowledge and it is easier to separate the host and the parasite using a number of parameters such as pharmacological properties, essential and unique enzymes.

The best antiparasitic medication should possess the following characteristics:

  • Effectiveness: They can actually get rid of the target parasites in all stages of their development.,
  • Safe: They don't cause discoloration of body fluids, don't cause withdrawal effects and don't interact with other drugs.,
  • Convenience: They are easy to administer and perform best with minimal dosage. ,
  • Affordable: These medicines should be affordable for all in need to manage targeted conditions.,

Doctor's Consultation

Even though it is easy to identify a parasitic infection, it is always advisable to leave the diagnosis to the doctors. A prescription should only be given after carrying out the right tests because that is the only way specific parasites will be determined and treatment decided. The best time to see the doctor is at the onset of the symptoms. Share your medical history, symptoms and any drugs you might be taking and for what conditions. Also remember to point out any allergies because some drugs might cause or worsen allergic reactions.

Common Antiparasitics

  • Aralen (Chloroquin) is used to treat malaria by killing and prevent multiplication of malaria parasites found in the red blood cells. To eliminate parasites in other body tissues, other drugs such as primaquine may be used.
  • Lariam (Mefloquine) is also used in the prevention and treatment of malaria.
  • Elimite (Permethrin) serves as both medicine and insecticide that used to treat scabies and kill lice. It is topically applied and comes in form of lotion or cream.
  • Vernox (Mebendazole) is mostly used in treating infections caused by or more of the following works; pinworm, roundworm, whipworm and hookworm.
  • Albenza (Albenzadole) is a prescription anthelmintic used to treat cystic hydatid and neurocysticercosis that are caused by dog and pork tapeworm respectively.

Side Effects and Precautions

While everything has been done to ensure that antiparasitics are safe for use, there is need to be cautious when using them. Some known drugs such as Albenza though effective in the treatment of varies parasitic infections, they can cause abdominal pain, headache, nausea and dizziness. Always report severe side effects to your doctor for timely attention.