Oxamniquine

Key takeaways

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

Reference excerpt

Oxamniquine, sold under the brand name Vansil among others, is a medication used to treat schistosomiasis due to Schistosoma mansoni. Praziquantel, however, is often the preferred treatment. It is given by mouth and used as a single dose. Common side effects include sleepiness, headache, nausea, diarrhea, and reddish urine. It is typically not recommended during pregnancy, if possible. Seizures may occur and therefore caution is recommended in people with epilepsy. It works by causing paralysis of the parasitic worms. It is in the anthelmintic family of medications. Oxamniquine was first used medically in 1972. It is on the World Health Organization's List of Essential Medicines. It is not commercially available in the United States. It is more expensive than praziquantel.

Medical uses Oxamniquine is used for treatment of schistosomiasis. According to one systematic review, praziquantel is the standard treatment for S. mansoni infections and oxamniquine also appears effective.

Side effects It is generally well tolerated following oral doses. Dizziness with or without drowsiness occurs in at least a third of patients, beginning up to three hours after a dose, and usually lasts for up to six hours. Headache and gastrointestinal effects, such as nausea, vomiting, and diarrhoea, are also common. Allergic-type reactions, including urticaria, pruritic skin rashes, and fever, may occur. Liver enzyme values have been raised transiently in some patients. Epileptiform convulsions have been reported, especially in patients with a history of convulsive disorders. Hallucinations and excitement have occurred rarely. A reddish discoloration of urine, probably due to a metabolite of oxamniquine, has been reported. Oxamniquine is not recommended during pregnancy.

Pharmacokinetics Peak plasma concentrations are achieved one to three hours after a dose, and the plasma half-life is 1.0 to 2.5 hours. It is extensively metabolised to inactive metabolites, principally the 6-carboxy derivative, which are excreted in the urine. About 70% of a dose of oxamniquine is excreted as the 6-carboxy metabolite within 12 hours of a dose; traces of the 2-carboxy metabolite have also been detected in the urine.

Mechanism of action It is an anthelmintic with schistosomicidal activity against Schistosoma mansoni, but not against other Schistosoma spp. Oxamniquine is a potent single-dose agent for treatment of S. mansoni infection, and it causes worms to shift from the mesenteric veins to the liver, where the male worms are retained; the female worms return to the mesentery, but can no longer release eggs. Oxamniquine is a semisynthetic tetrahydroquinoline and possibly acts by DNA binding, resulting in contraction and paralysis of the worms and eventual detachment from terminal venules in the mesentery, and death. Its biochemical mechanisms are hypothesized to be related to an anticholinergic effect, which increases the parasite's motility, as well as inhibiting the synthesis of nucleic acids. Oxamniquine acts mainly on male worms, but also induces small changes on a small proportion of females. Like praziquantel, it promotes more severe damage of the dorsal tegument than of the ventral surface. The drug causes the male worms to shift from the mesenteric circulation to the liver, where the cellular host response causes its final elimination. The changes caused in the females are reversible and are due primarily to the discontinued male stimulation rather than the direct effect of oxamniquine.

History Oxamniquine was first described by Kaye and Woolhouse in 1972 as a metabolite of the compound UK 3883 (2-isopropylaminomethyl-6-methyl-7-nitro-1,2,3,4-tetrahydroquinoline). Initially, it was prepared by enzymatic hydroxylation via the fungus Aspergillus sclerotiorum. In 1979, Pfizer at Sandwich was presented with the Queen's Award for Technological Achievement in recognition of the outstanding contribution made to tropical medicine by MANSIL (oxamniquine).

Brand names Vansil; (Pfizer) 250 mg capsules, syrup 250 mg/5 mL Mansil; 250 mg Tablets

Stereochemistry Oxamniquine contains a stereocenter and consists of two enantiomers. This is a racemate, i.e. a 1: 1 mixture of ( R ) - and the ( S ) - form:

References

External links "Oxamniquine". Drugs.com. Archived from the original on 5 March 2016. Retrieved 23 January 2018. "Schistosomiasis treatment". Institute of Tropical Medicine. Antwerp. Archived from the original on 22 November 2004.

Illustrations

Worked examples

Example 1 — a first encounter with Oxamniquine

Start with the simplest possible case. Write down what Oxamniquine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Oxamniquine 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 Oxamniquine 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 Oxamniquine

In research: Oxamniquine appears in biology 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 Oxamniquine 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: Oxamniquine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antiparasitic agents, Nitroarenes, Primary alcohols, so understanding it makes those chapters shorter.
In everyday life: Look for Oxamniquine 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.

How to study Oxamniquine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Oxamniquine 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 Oxamniquine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Oxamniquine in simple terms?

Oxamniquine, sold under the brand name Vansil among others, is a medication used to treat schistosomiasis due to Schistosoma mansoni. Praziquantel, however, is often the preferred treatment.

Why does Oxamniquine matter?

Because it connects several biology 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 Oxamniquine?

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 Oxamniquine.