chemistry

Praziquantel

Praziquantel is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Praziquantel rather than just read about it. In short: Praziquantel, sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat schistosomiasis, clonorchiasis, opisthorchiasis, tapeworm infections, cysticercosis, echinococcosis, paragonimiasis, fasciolopsiasis, and fasciolosis.

Key takeaways

Praziquantel belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Praziquantel to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Praziquantel from memory before moving on to harder problems.

Reference excerpt

Praziquantel, sold under the brandname Biltricide among others, is a medication used to treat a number of types of parasitic worm infections in mammals, birds, amphibians, reptiles, and fish. In humans specifically, it is used to treat schistosomiasis, clonorchiasis, opisthorchiasis, tapeworm infections, cysticercosis, echinococcosis, paragonimiasis, fasciolopsiasis, and fasciolosis. It should not be used for worm infections of the eye. It is taken by mouth. Side effects in humans may include poor coordination, abdominal pain, vomiting, headache, and allergic reactions. While it may be used during pregnancy, it is not recommended for use during breastfeeding. Praziquantel is in the anthelmintic class of medications. It works partly by affecting the function of the worm's sucker. Praziquantel was approved for medical use in the United States in 1982, and in the European Union in April 2025. It is on the World Health Organization's List of Essential Medicines.

Medical uses Praziquantel is used to treat diseases caused by infection with several types of internal/gastrointestinal, and external parasites, including:

Schistosomiasis caused by trematodes of the genus Schistosoma: As of 2005, praziquantel is the primary treatment for human schistosomiasis, for which it is usually effective in a single dose Hydatid disease caused by infection of various organs with larval stages of tapeworms of the genus Echinococcus Cysticercosis caused by infection of the brain and/or muscles with the eggs and larvae of the pork tapeworm Taenia solium (though it has been judged less effective than albendazole in treatment of neurocysticercosis) Taeniasis caused by intestinal infection with Taenia saginata and Taenia solium Diphyllobothriasis caused by intestinal infection with Diphyllobothrium latum Hymenolepiasis caused by Hymenolepis nana and Hymenolepis diminuta Bertielliasis caused by intestinal infection with Bertiella studeri In dogs and cats, whose gastrointestinal tracts are infected with the tapeworms Dipylidium caninum or Taenia taeniaeformis, respectively; praziquantel is also often used in fixed combination with pyrantel embonate against the roundworms (ascarids): Toxocara cati and Toxascaris leonina. Praziquantel is also effective against Echinococcus multilocularis. Clonorchiasis brought on by the Chinese liver fluke Clonorchis sinensis Opisthorchiasis brought on by the liver flukes Opisthorchis viverrini and Opisthorchis felineus Paragonimiasis caused by infection with lung flukes, mostly of the species Paragonimus westermani Fasciolopsiasis caused by the giant intestinal fluke Fasciolopsis buski Echinostomiasis caused by infection with intestinal flukes of the genus Echinostoma Metagonimiasis caused by infection with intestinal flukes of the genus Metagonimus Heterophyiasis caused by the intestinal fluke Heterophyes heterophyes Gastrodiscoidiasis caused by the intestinal fluke Gastrodiscoides hominis

Side effects The majority of side effects develop due to the release of the contents of the parasites as they are killed and the consequent host immune reaction. The heavier the parasite burden, the heavier and more frequent the side effects normally are.

Central nervous system (CNS): Frequently occurring side effects are dizziness, headache, and malaise. Drowsiness, somnolence, fatigue, and vertigo have also been seen. Almost all patients with cerebral cysticercosis experience CNS side effects related to the cell-death of the parasites (headache, worsening of pre-existing neurological problems, seizures, arachnoiditis, and meningism). These side effects may be life-threatening and can be reduced by coadministration of corticosteroids. All patients with cerebral cysticercosis are strongly recommended to be hospitalized during treatment. Gastrointestinal tract: About 90% of all patients have abdominal pain or cramps with or without nausea and vomiting. Diarrhea may develop and may be severe with colic. Sweating, fever, and sometimes bloody stools may occur together with diarrhea. Praziquantel also has a bitter taste that can result in gagging or vomiting. Liver: Asymptomatic and transient increases of liver enzymes (AST and ALT) are noted frequently (up to 27%). No case of symptomatic liver damage has been seen so far. Sensitivity reactions: Urticaria, rash, pruritus and eosinophilia in white blood cell counts Other locations/body as a whole: Lower back pain, myalgia, arthralgia, fever, sweating, various cardiac arrhythmias, and hypotension

Pregnancy The WHO states praziquantel is safe during pregnancy (although does not recommend use during the first trimester). Animal studies have failed to reveal evidence of fetal harm. Praziquantel is effective in reducing schistosomiasis during pregnancy. Another trial found that treatment with praziquantel did not increase the rates of low birthweight, fetal death, or congenital anomalies.

Drug interactions Co-administration of drugs that inhibit the activity of drug metabolizing liver enzymes such as (CYP450), e.g., cimetidine, ketoconazole, itraconazole, erythromycin, and ritonavir, may increase plasma concentrations of praziquantel. The antibiotic rifampicin, a strong CYP450 inducer, decreases plasma concentrations of praziquantel. Carbamazepine and phenytoin are reported to reduce the bioavailability of praziquantel. Chloroquine also reduces its bioavailability.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Praziquantel

Start with the simplest possible case. Write down what Praziquantel claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Praziquantel before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Praziquantel ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Praziquantel

In research: Praziquantel appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Praziquantel in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Praziquantel is common in secondary-school and first-year university syllabi. It links to neighbouring topics Anthelmintics, Antiparasitic agents, Carboxamides, so understanding it makes those chapters shorter.
In everyday life: Look for Praziquantel outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Praziquantel in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Praziquantel means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Praziquantel out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Praziquantel in simple terms?

Why does Praziquantel matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Praziquantel?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Praziquantel.