science

Pemoline

Pemoline is a science 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 Pemoline rather than just read about it. In short: Pemoline, formerly sold under the brand name Cylert among others, is a stimulant medication which was used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It has since been discontinued in most countries due to rare but serious liver toxicity.

Key takeaways

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

Reference excerpt

Pemoline, formerly sold under the brand name Cylert among others, is a stimulant medication which was used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy. It has since been discontinued in most countries due to rare but serious liver toxicity. The medication was taken by mouth. Common side effects include insomnia, decreased appetite, abdominal pain, irritability, and headaches, while rare cases of serious liver damage requiring liver transplantation or causing death have been reported. As a stimulant, pemoline acts as a selective dopamine reuptake inhibitor and releasing agent via indirect agonism of dopamine receptors. In addition, it shows little activity with respect to norepinephrine, thus minimal to no cardiovascular or sympathomimetic effects in comparison to many other stimulants. Pemoline was first synthesized in 1913, but its stimulant activity was not discovered until the 1930s, nor used for ADHD until 1975. Between 1997 and 2005, many countries, including the United States, withdrew the drug due to liver toxicity. However, it remains available in Japan for the treatment of narcolepsy at lower doses than those used for ADHD. Pemoline is a schedule IV controlled substance in the United States due to structural and functional similarity to other stimulants, and potential for misuse. However, it is noted to have less misuse potential than other stimulant drugs.

Medical uses Pemoline has been used in the treatment of ADHD and narcolepsy. It has also been used in the treatment of excessive daytime sleepiness. The medication was typically used at doses of 18.75 to 112.5 mg once per day in the treatment of ADHD, with the effective dose for most people being in the range of 56.25 to 75 mg. The onset of action of pemoline is gradual and therapeutic benefits may not occur until the third or fourth weeks of use. This may be due to a cautious low initial starting dose of 37.5 mg and gradual titration in dose upwards over several weeks.

Available forms Pemoline was available in the form of 18.75, 37.5, and 75 mg oral immediate-release tablets (Cylert) as well as 37.5 mg oral immediate-release chewable tablets. It was provided mainly in the form of the free base but also as the magnesium salt.

Side effects Side effects of pemoline include insomnia, decreased appetite, abdominal pain, irritability, and headaches. It has minimal cardiovascular or sympathomimetic side effects. Pemoline is described as a lower-efficacy/milder stimulant than classical stimulants like amphetamines and methylphenidate and is said to have fewer side effects than them.

Liver toxicity Rarely, pemoline is implicated in causing hepatotoxicity. Because of this, the FDA recommended that regular liver tests be performed in those treated with it. Since being introduced, it has been linked with at least 21 cases of liver failure, of which 13 resulted in liver replacement or death. Approximately 1–2% of patients taking the drug show elevated levels of liver transaminase enzymes, a marker for liver toxicity, though serious cases are rare. Over 200,000 children with ADHD were prescribed pemoline in the United States and Canada alone during the approximate 25 years that it was available, plus a smaller number of adults prescribed it for other indications (and not including prescriptions in the rest of the world). As such, the number of liver failure cases was statistically not that large. However the reactions proved idiosyncratic and unpredictable, with patients sometimes taking the drug with no issue for months or even years, before suddenly developing severe liver toxicity. There was no clear exposure–toxicity relationship, and no characteristic liver pathology findings. Some patients showed as little as one week between first appearance of jaundice and complete liver failure, and some of the patients that developed liver failure had not showed elevated liver transaminase levels when tested previously. On the other hand, there are no cases of liver failure associated with pemoline in Japan, although it is used at lower doses and is only prescribed for the niche indication of narcolepsy in this country.

Overdose Overdose of pemoline may present with choreoathetosis symptoms.

Interactions Other stimulants and monoamine oxidase inhibitors are contraindicated with pemoline.

Pharmacology

Pharmacodynamics The pharmacodynamics of pemoline are poorly understood and its precise mechanism of action hasn't been definitively determined. However, pemoline has similar activity and effects to those of other psychostimulants, and in animals the medication appears to act as a dopamine reuptake inhibitor and releasing agent. By increasing dopamine levels in the brain, it functions as an indirect agonist of dopamine receptors. In contrast to most other stimulants, pemoline appears to produce no significant central or peripheral noradrenergic effects. As a result, it has minimal or no cardiovascular or sympathomimetic effects. Pemoline is described as a selective dopamine reuptake inhibitor that only weakly stimulates dopamine release. While drugs like dextroamphetamine and methylphenidate are classified as schedule II and have considerable misuse potential, pemoline is listed as schedule IV (non-narcotic). In studies conducted on primates, pemoline fails to demonstrate a potential for self-administration. It is thought to have little potential for abuse and dependence. Nonetheless, misuse may theoretically occur owing to its similarity to other psychostimulants.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Pemoline

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

In research: Pemoline appears in science 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 Pemoline 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: Pemoline is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aminorexes, Drugs developed by AbbVie, Hepatotoxins, so understanding it makes those chapters shorter.
In everyday life: Look for Pemoline 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 Pemoline in 20 minutes

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

Frequently asked questions

What is Pemoline in simple terms?

Why does Pemoline matter?

Because it connects several science 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 Pemoline?

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 Pemoline.