The substance praziquantel is effective against worm infestation in both humans and animals. It fights various types of worms and kills them. The duration of intake depends individually on the strength and type of worm infestation.
What is praziquantel?
The substance praziquantel is effective against worm infestation in both humans and animals. Praziquantel is a so-called anthelmintic (anthelmintic) that is effective against flatworms and tapeworms, as well as against sucking worms 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 used as the drug of choice against worm infestations in both human and veterinary medicine.
Pharmacological action
Praziquantel causes calcium channels in the skin to open in worms. This results in hyperexcitation of the muscles and spastic paralysis of the worms. This eventually leads to the death of the parasite. Furthermore, the active ingredient attacks the skin of the worms and disturbs their metabolism, so that they can be more easily recognized and attacked by the immune system. The killed parasites are finally excreted via the digestive system in the case of an internal infestation. Because the active ingredient penetrates all the way to the brain, praziquantel is well suited as a medicine to combat diseases in which worms have taken up residence in the brain (e.g., dwarf tapeworm, bovine tapeworm, fish tapeworm, or pork tapeworm).
Medical application and use
The active ingredient ‘praziquantel is administered by swallowing (peroral), and the dose in each case depends individually on the type of worm infestation and also on its distribution in the affected organism. There are tapeworms for which the administration of a single and low dose (about 10 to 25 milligrams per kilo of body weight) of the substance is already sufficient for killing. In other cases, for example when internal organs or the central nervous system are infested by worms, a therapy of up to two weeks with a maximum dose (up to 50 milligrams per kilogram of body weight) must be consistently carried out to kill the parasites. The active substance against worms is also approved for treatment of children with a body weight of 20 kilograms or more. It crosses the blood–brain barrier and is therefore considered particularly effective. So far, no resistance to praziquantel has been demonstrated in worms either. Praziquantel has also been used by the WHO (World Health Organization) since 2007 specifically to eradicate the dangerous worm disease schistosomiasis. Bilharzia is an infection caused by flukes, in which the flukes’ 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. The free use of praziquantel has so far made it possible to treat more than 27 million children in the affected regions. If a worm infestation is suspected, it is generally very important to see a doctor, because only he or she can determine the exact type of worm, the location of infestation and the density of infestation, and then determine the individually appropriate dose and duration of intake of a drug such as praziquantel.
Risks and side effects
The risks and side effects of praziquantel depend firstly on the amount of the dose, and secondly on the duration of intake and the infected 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 are very rare with use of the drug. In case of simultaneous use of the antimalarial drug chloroquine or antiepileptic drugs, the concentration of the substance in the blood may decrease, so that the effect is limited. Patients with impaired liver or kidney function and with cardiac arrhythmias should take praziquantel only with careful monitoring.