Active Ingredients

Praziquantel – Effect, Application & Risks


The substance praziquantel is effective against worm infestation in both humans and animals. It fights and kills different types of worms. The duration of intake depends on the severity and type of worm infestation.

What is praziquantel?

Praziquantel is a so-called anthelmintic (antiworm agent) that is effective against flatworms and tapeworms as well as against flukes and some flukes.

The active ingredient was developed in the 1970s by Bayer AG in cooperation with Merck and has been on the market since the 1980s. Today, praziquantel is the drug of choice in both human and veterinary medicine against infestation with worms.

Pharmacological action

In the worms, praziquantel ensures that calcium channels in the skin open. The muscles become overexcited and the worms become spastic. This eventually leads to the death of the parasite

Furthermore, the active ingredient attacks the skin of the worms and disrupts their metabolism so that they can be more easily recognized and attacked by the immune system. The killed parasites are finally excreted through the digestive system in the event of an internal infestation.

Since the active ingredient penetrates into the brain , praziquantel is a good drug to combat diseases in which worms have lodged in the brain (eg tapeworm, beef, fish or pork).

Medical Application & Use

The active substance ‘ praziquantel ‘ is administered by swallowing (perorally), with the respective dose depending on the type of worm infestation and also on its distribution in the infested organism. There are tapeworms for which the administration of a single, low dose (about 10 to 25 milligrams per kilogram of body weight) of the substance is sufficient to kill them.

In other cases, for example, if internal organs or the central nervous system are infested with worms, a therapy of up to two weeks with a maximum dose (up to 50 milligrams per kilogram of body weight) must be carried out consistently to kill the parasites. The active ingredient against worms is also approved for the treatment of children with a body weight of 20 kg or more. It crosses the blood-brain barrier and is therefore considered to be particularly effective. Resistance to praziquantel in worms has not yet been demonstrated.

Praziquantel has also been used by the WHO (World Health Organization) since 2007 to eradicate the dangerous worm disease schistosomiasis . This is an infection caused by paired flukes, in which the fluke larvae spread through the intestines , liver and lungs to the brain. The disease is spread by snails as intermediate hosts in warm inland waters, especially in Africa, South America, the Arabian Peninsula and the Caribbean.

So far, more than 27 million children in the affected regions have been treated thanks to the free use of praziquantel. If a worm infestation is suspected, going to the doctor is generally very important, because only he can determine the exact type of worm, the location of the infestation and the density of the infestation and then determine the individually appropriate dose and duration of administration of a drug such as praziquantel.

Risks & side effects

The risks and side effects of praziquantel depend on the one hand on the amount of the dose, on the other hand on the duration of intake and the affected organism (human or animal).

In humans, abdominal pain , nausea , and vomiting are very common side effects, especially at higher doses. Furthermore, weakness and fatigue as well as the formation of wheals on the skin and itching can occur as very common side effects.

Dizziness , fatigue , loss of appetite , and muscle pain are also common. Hypersensitivity reactions and cardiac arrhythmias when using the active substance are very rare. If the antimalarial drug chloroquine or antiepileptic drugs are taken at the same time, the concentration of the substance in the blood can be reduced, limiting the effect. Patients with impaired liver or kidney function and with cardiac arrhythmias should only take praziquantel if they are carefully monitored.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.