chemistry

Neostigmine

Neostigmine 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 Neostigmine rather than just read about it. In short: Neostigmine, sold under the brand name Bloxiverz, among others, is a medication used to treat myasthenia gravis, Ogilvie syndrome, and urinary retention without the presence of a blockage. It is also used in anaesthesia to end the effects of non-depolarising neuromuscular blocking medication.

Key takeaways

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

Reference excerpt

Neostigmine, sold under the brand name Bloxiverz, among others, is a medication used to treat myasthenia gravis, Ogilvie syndrome, and urinary retention without the presence of a blockage. It is also used in anaesthesia to end the effects of non-depolarising neuromuscular blocking medication. It is given by injection either into a vein, muscle, or under the skin. After injection effects are generally greatest within 30 minutes and last up to 4 hours. Common side effects include nausea, increased saliva, crampy abdominal pain, and slow heart rate. More severe side effects include low blood pressure, weakness, and allergic reactions. It is unclear if use in pregnancy is safe for the fetus. Neostigmine is in the cholinergic family of medications. It works by blocking the action of acetylcholinesterase and butyrylcholinesterase and therefore increases the levels of acetylcholine. Neostigmine was patented in 1931. It is on the World Health Organization's List of Essential Medicines. The term is from Greek neos, meaning "new", and "-stigmine", in reference to the alkaloid, physostigmine, which inspired its design. It is available as a generic medication.

Medical uses It is used to improve muscle tone in people with myasthenia gravis, and also to reverse the effects of non-depolarizing muscle relaxants such as rocuronium and vecuronium at the end of an operation. Another indication for use is the conservative management of acute colonic pseudo-obstruction, or Ogilvie's syndrome, in which patients get massive colonic dilatation in the absence of a true mechanical obstruction. Neostigmine is often prescribed for underactive urinary bladder. Hospitals sometimes administer a solution containing neostigmine intravenously to delay the effects of envenomation through snakebite. Some promising research results have also been reported for administering the drug nasally in order to buy time if anti-venom is not immediately available.

Side effects Neostigmine has a wide variety of side-effects due to its action that increases acetylcholine (ACh) binding muscarinic receptors on exocrine glandular cells throughout the body, cardiac muscle cells, and smooth muscle cells. These effects include: salivation, lacrimation, diarrhea, bradycardia, and bronchoconstriction. Gastrointestinal symptoms occur earliest. For this reason, it is usually given along with an anti-cholinergic drug such as atropine or glycopyrrolate which act only on muscarinic receptors while permitting neostigmine action at nicotinic receptors. Neostigmine can also induce generic ocular side effects including: headache, brow pain, blurred vision, phacodonesis, pericorneal injection, congestive iritis, various allergic reactions, and rarely, retinal detachment.

Pharmacology Acetylcholine is metabolized by either the enzyme acetylcholinesterase or butyrylcholinesterase that cleaves acetylcholine in the neuromuscular junction into acetate and choline. Neostigmine is an inhibitor of both. Neostigmine binds to the anionic and ester site of acetylcholinesterase, which blocks the enzyme from breaking down the acetylcholine molecules before they reach the postsynaptic membrane receptors. Its action leads to the accumulation of acetylcholine in the neuromuscular junction that compete with the non-depolarizing blocker agent bound to the acetylcholine receptors. By interfering with the breakdown of acetylcholine, neostigmine indirectly stimulates both nicotinic and muscarinic receptors. Unlike physostigmine, neostigmine has a quaternary nitrogen; hence, it is more polar. It does not cross the blood–brain barrier and enter the CNS. Neostigmine is administered intravenously. The drug should be administered when a peripheral nerve stimulator shows a second twitch is present or when the first twitch response is considerably above 10% of baseline. Peak effect is at 7 to 10 minutes. Neostigmine has moderate duration of action – usually two to four hours. It is metabolized by enzymes in the liver and excreted in the urine.

Chemistry Neostigmine, which can be viewed as a simplified analog of physostigmine, is made by reacting 3-dimethylaminophenol with N-dimethylcarbamoyl chloride, which forms the dimethylcarbamate, and its subsequent alkylation using dimethyl sulfate forming the desired compound.

Spectral data Neostigmine shows notable UV/VIS absorption at 261 nm, 267 nm, and 225 nm. Neostigmine's 1H NMR Spectroscopy reveals shifts at: 7.8, 7.7, 7.4, 7.4, 3.8, and 3.1 parts per million. The higher shifts are due to the aromatic hydrogens. The lower shifts at 3.8 ppm and 3.1 ppm are due to the electronic withdrawing nature of the tertiary and quaternary nitrogen, respectively.

History Neostigmine was first synthesized by Aeschlimann and Reinert in 1931 and was patented by Aeschlimann in 1933. Neostigmine is made by first reacting 3-dimethylaminophenol with N-dimethylcarbamoyl chloride, which forms a dimethylcarbamate. Next, that product is alkylated using dimethyl sulfate, which forms neostigmine.

References

External links "Neostigmine". Drug Information Portal. U.S. National Library of Medicine. 16 August 2022. Archived from the original on 28 June 2019. "Neostigmine methylsulfate". Drug Information Portal. U.S. National Library of Medicine. 16 August 2022. Archived from the original on 28 June 2019. "Neostigmine bromide". Drug Information Portal. U.S. National Library of Medicine. 16 August 2022. Archived from the original on 29 October 2020.

Illustrations

Worked examples

Example 1 — a first encounter with Neostigmine

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

In research: Neostigmine 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 Neostigmine 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: Neostigmine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Acetylcholinesterase inhibitors, Aromatic carbamates, Dimethylamino compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Neostigmine 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 Neostigmine in 20 minutes

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

Frequently asked questions

What is Neostigmine in simple terms?

Why does Neostigmine 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 Neostigmine?

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 Neostigmine.