Pentoxyverine

Key takeaways

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

Reference excerpt

Pentoxyverine (rINN) or carbetapentane is an antitussive (cough suppressant) commonly used for cough associated with illnesses like common cold. It is sold over-the-counter as Solotuss, or in combination with other medications, especially decongestants. One such product is Certuss, a combination of guaifenesin and pentoxyverine. The drug has been available in the form of drops, suspensions and suppositories. It was formerly available over-the-counter in United States. However, the U.S. Food & Drug Administration ruled in 1987 that pentoxyverine was not generally recognized as safe and effective and ordered it to be removed from the over-the-counter market.

Uses The drug is used for the treatment of dry cough associated with conditions such as common cold, bronchitis or sinusitis. Like codeine and other antitussives, it relieves the symptom, but does not heal the illness. No controlled clinical trials regarding the efficiency of pentoxyverine are available. Pharmacologists use the substance as a selective agonist at the sigma-1 receptor in animal and in vitro experiments.

Contraindications Pentoxyverine is contraindicated in persons with bronchial asthma or other kinds of respiratory insufficiency (breathing difficulties), as well as angle-closure glaucoma. No data are available for the use of pentoxyverine during pregnancy, lactation, or children under two years of age, wherefore the drug must not be used under these circumstances. Antitussive drugs are not useful in patients with extensive phlegm production because they prevent coughing up the phlegm.

Adverse effects The most common side effects (seen in more than 1% of patients) are upper abdominal (belly) pain, diarrhoea, dry mouth, and nausea or vomiting. Allergic reactions of the skin like itching, rashes, hives and angiooedema are rare. The same is true for anaphylactic shock and convulsions.

Overdose Overdosage leads to drowsiness, agitation, nausea and anticholinergic effects like tachycardia (high heart rate), dry mouth, blurred vision, glaucoma, or urinary retention. Especially in children, pentoxyverine can cause hypoventilation, but much more seldom than codeine and other opioid antitussives. The treatment of overdosage aims at the symptoms; there are no specific antidotes available.

Interactions No interactions have been described at usual doses. It is possible that pentoxyverine can increase the potency of sedative drugs like benzodiazepines, some anticonvulsants and antidepressants, and alcohol. Likewise, some consumer informations warn patients from taking the drug in combination with or up to two weeks after monoamine oxidase inhibitors, which are known to cause potentially fatal reactions in combination with the (chemically only distantly related) antitussive dextromethorphan.

Mechanism of action Pentoxyverine is believed to suppress the cough reflex in the central nervous system, but the exact mechanism of action is not known with certainty. The drug acts as an antagonist at muscarinic receptors (subtype M1) and as an agonist at sigma receptors (subtype σ1) with an IC50 of 9 nM. Its anticholinergic properties can theoretically relax the pulmonary alveoli and reduce phlegm production. Spasmolytic and local anaesthetic properties have also been described. The clinical relevance of these mechanisms is uncertain.

Pharmacokinetics The substance is absorbed quickly from the gut and reaches its maximum plasma concentration (Cmax) after about two hours. If applied rectally, Cmax is reached after four hours. The bioavailability of the suppositories, measured as area under the curve (AUC), is about twofold that of oral formulations, due to a first pass effect of over 50%. By far the most important metabolisation reaction is ester hydrolysis, which accounts for 26.3% of the total clearance through the kidneys. Only 0.37% are cleared in form of the original substance. The plasma half life is 2.3 hours for oral formulations and three to 3.5 hours for suppositories. Pentoxyverine is also excreted into the breast milk.

Chemical properties Pentoxyverine dihydrogen citrate, the salt that is commonly used for oral preparations, is a white to off-white, crystalline powder. It dissolves easily in water or chloroform, but not in benzene, diethyl ether, or petroleum ether. It melts at 90 to 95 °C (194 to 203 °F). Other orally available salts are the hydrochloride and the tannate; suppositories contain the free base.

See also Cough syrup Noscapine Codeine; Pholcodine Dextromethorphan; Dimemorfan Racemorphan; Dextrorphan; Levorphanol Butamirate Tipepidine Cloperastine; Levocloperastine

References

Illustrations

Worked examples

Example 1 — a first encounter with Pentoxyverine

Start with the simplest possible case. Write down what Pentoxyverine 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 Pentoxyverine 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 Pentoxyverine 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 Pentoxyverine

In research: Pentoxyverine 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 Pentoxyverine 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: Pentoxyverine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antitussives, Carboxylate esters, Cyclopentanes, so understanding it makes those chapters shorter.
In everyday life: Look for Pentoxyverine 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 Pentoxyverine in 20 minutes

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

Frequently asked questions

What is Pentoxyverine in simple terms?

Pentoxyverine (rINN) or carbetapentane is an antitussive (cough suppressant) commonly used for cough associated with illnesses like common cold. It is sold over-the-counter as Solotuss, or in combination with other medications, especially decongestants.

Why does Pentoxyverine 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 Pentoxyverine?

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 Pentoxyverine.