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chemistry

Methaqualone

Methaqualone 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 Methaqualone rather than just read about it. In short: Methaqualone is a sedative-hypnotic medication that was widely prescribed during the mid-20th century. It was marketed under various brand names, including Quaalude ( KWAY-lood) and Sopor, typically containing 300 mg of methaqualone per tablet.

Methaqualone — main illustration
Methaqualone — illustration

Key takeaways

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

Reference excerpt

Methaqualone is a sedative-hypnotic medication that was widely prescribed during the mid-20th century. It was marketed under various brand names, including Quaalude ( KWAY-lood) and Sopor, typically containing 300 mg of methaqualone per tablet. A combination drug known as Mandrax was sold primarily in Europe, containing 250 mg of methaqualone and 20 mg of diphenhydramine in a single tablet. Methaqualone belongs to the quinazolinone class of compounds. Its commercial production was discontinued in many countries during the mid-1980s due to widespread misuse, addiction, and associated public health concerns. However, methaqualone continues to be used as a recreational drug in certain places such as South Africa and elsewhere up to the present. In addition, methaqualone analogues with at least 100-fold greater potency than methaqualone itself such as mephenaqualone have emerged as novel designer drugs in the late 2010s and early 2020s.

Medical use Methaqualone's sedative-hypnotic properties were first identified in 1955. It gained popularity during the 1960s and 1970s for the treatment of insomnia, and as a general sedative and muscle relaxant. However, due to its abuse potential, it was eventually withdrawn from medical use. The drug was classified as pregnancy category D, meaning there was evidence of risk to the human fetus, and it was not recommended during pregnancy. Like other GABAergic substances, prolonged use of methaqualone can lead to drug tolerance, physical dependence, and withdrawal symptoms upon cessation.

Overdose An overdose of methaqualone can lead to coma and death. Additional effects are delirium, convulsions, hypertonia, hyperreflexia, vomiting, kidney failure, and death through cardiac or respiratory arrest. Methaqualone overdose resembles barbiturate poisoning, but with increased motor difficulties and a lower incidence of cardiac or respiratory depression. The standard single tablet adult dose of Quaalude brand of methaqualone was 300 mg when made by Lemmon. A dose of 8000 mg is lethal and a dose as little as 2000 mg could induce a coma if taken with an alcoholic beverage.

Pharmacology

Pharmacodynamics Methaqualone acts primarily as a sedative, reducing anxiety and inducing sleep. It binds to GABAA receptors, where it functions as a positive allosteric modulator at many receptor subtypes, enhancing the inhibitory effects of the neurotransmitter GABA. It shows negligible affinity for a wide array of other potential targets, including other receptors and neurotransmitter transporters. This action is similar to that of benzodiazepines like diazepam. Unlike most benzodiazepines, however, methaqualone may also act as a negative allosteric modulator at certain GABAA receptor subtypes, producing excitatory effects in neurons expressing those receptors. As such, methaqualone is considered a mixed GABAA receptor modulator. The binding site for methaqualone on the GABAA receptor complex is distinct from those of benzodiazepines, barbiturates, and neurosteroids, though it may partially overlap with the etomidate binding site.

Pharmacokinetics Methaqualone reaches peak plasma concentrations within a few hours of administration. Its elimination half-life ranges between 20 and 60 hours, contributing to its sedative effects and potential for accumulation with repeated dosing.

Chemistry

Analogues

Analogues of methaqualone with at least 100-fold greater potency such as mephenaqualone have been described.

History Methaqualone was first synthesized in India in 1951 by Indra Kishore Kacker and Syed Husain Zaheer, who were conducting research on finding new antimalarial medications. In 1962, methaqualone was patented in the United States by Wallace and Tiernan. By 1965, it was the most commonly prescribed sedative in Britain, where it has been sold legally under the names Malsed, Malsedin, and Renoval. In 1965, a methaqualone/antihistamine combination was sold as the sedative drug Mandrax in Europe, by Roussel Laboratories (now part of Sanofi S.A.). In 1972, it was the sixth-bestselling sedative in the US, where it was legal under the brand name Quaalude. Sold in the United States under the brand name Quaalude, methaqualone was moved to Schedule I in 1984 after prescription controls failed to curb diversion. Quaalude in the United States was originally manufactured in 1965 by the pharmaceutical firm William H. Rorer, Inc., based in Fort Washington, Pennsylvania. The drug name "Quaalude" is a portmanteau, combining the words "quiet interlude" and shared a stylistic reference to another drug marketed by the firm, Maalox. In 1978, Rorer sold the rights to manufacture Quaalude to the Lemmon Company of Sellersville, Pennsylvania. At that time, Rorer chairman John Eckman commented on Quaalude's bad reputation stemming from illegal manufacture and use of methaqualone, and illegal sale and use of legally prescribed Quaalude: "Quaalude accounted for less than 2% of our sales, but created 98% of our headaches." Both companies still regarded Quaalude as an excellent sleeping drug. Lemmon, well aware of Quaalude's public image problems, used advertisements in medical journals to urge physicians "not to permit the abuses of illegal users to deprive a legitimate patient of the drug". Lemmon also marketed a small quantity under another name, Mequin, so doctors could prescribe the drug without the negative connotations. The rights to Quaalude were held by the JB Roerig & Company division of Pfizer, before the drug was discontinued in the United States in 1985, mainly due to its psychological addictiveness, widespread abuse, and illegal recreational use. A 2024 Hungarian investigative documentary reported on large-scale production and sales of the drug by the Hungarian People's Republic to the United States in the 1970s and 1980s. It asserts that a Hungarian state-owned company utilized connections to Colombian drug cartels to facilitate the sale of extraordinary amounts to the United States.

Brand names Methaqualone was sold under the brand name Quaalude (sometimes stylized "Quāālude" in the United States and Canada), and Mandrax in the UK, South Africa, and Australia.

… excerpt ends here. Continue reading the full article.

Illustrations

Methaqualone illustration
Methaqualone illustration
Methaqualone: A variety of methaqualone pills and capsules
A variety of methaqualone pills and capsules

Worked examples

Example 1 — a first encounter with Methaqualone

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

In research
Methaqualone 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 Methaqualone 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
Methaqualone is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2-Tolyl compounds, Amidines, GABAA receptor positive allosteric modulators, so understanding it makes those chapters shorter.
In everyday life
Look for Methaqualone 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 Methaqualone in 20 minutes

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

Frequently asked questions

What is Methaqualone in simple terms?

Methaqualone is a sedative-hypnotic medication that was widely prescribed during the mid-20th century. It was marketed under various brand names, including Quaalude ( KWAY-lood) and Sopor, typically containing 300 mg of methaqualone per tablet.

Why does Methaqualone 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 Methaqualone?

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 Methaqualone.

Tags

  • 2-Tolyl compounds
  • Amidines
  • GABAA receptor positive allosteric modulators
  • Hypnotics
  • Quinazolinones
  • Sedatives
  • South Africa and weapons of mass destruction
  • Withdrawn drugs

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