chemistry

Ritodrine

Ritodrine 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 Ritodrine rather than just read about it. In short: Ritodrine, formerly sold under the brand name Yutopar among others, is a tocolytic drug used to stop premature labor. It was withdrawn from the US market, according to the FDA Orange Book.

Key takeaways

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

Reference excerpt

Ritodrine, formerly sold under the brand name Yutopar among others, is a tocolytic drug used to stop premature labor. It was withdrawn from the US market, according to the FDA Orange Book. It was available in oral tablets or as an injection and was typically used as the hydrochloride salt. The drug acts as a selective β2-adrenergic receptor agonist. It was first approved for medical use in the United States in 1984.

Medical uses Ritodrine is used to treat preterm labor.

Contraindications Possible contraindications of ritodrine include type 2 diabetes, high blood pressure, and migraines.

Side effects Most side effects of β2-adrenergic receptor agonists result from their concurrent β1-adrenergic receptor agonistic activity, and include increase in heart rate, rise in systolic blood pressure, decrease in diastolic blood pressure, chest pain secondary to myocardial infarction, and arrhythmia. β-Adrenergic receptor agonists may also cause fluid retention secondary to decrease in water clearance, which when added to the tachycardia and increased myocardial work, may result in heart failure. In addition, they increase gluconeogenesis in the liver and muscle resulting in hyperglycemia, which increases insulin requirements in diabetic patients. The passage of β-adrenergic receptor agonists through the placenta does occur and may be responsible for fetal tachycardia, as well as hypoglycemia or hyperglycemia at birth. It has also been associated with postpartum bleeding. Ritodrine has been reported rarely to cause serious side effects including rhabdomyolysis, hepatotoxicity, leukopenia, pulmonary edema, and psychiatric symptoms, among others.

Pharmacology

Pharmacodynamics Ritodrine is a short-acting β2-adrenergic receptor agonist – a class of medication used for smooth muscle relaxation (other similar drugs are used in asthma or other pulmonary diseases such as salbutamol [albuterol]). Since ritodrine has a bulky N-substituent, it has high β2-adrenergic receptor selectivity. Also, the 4-hydroxy group on the benzene ring is important for activity as it is needed to form hydrogen bonds. Since the drug is β2-selective, it is used for premature labor.

Pharmacokinetics The 4-hydroxy group of ritodrine makes it susceptible to metabolism by catechol-O-methyl transferase (COMT).

Chemistry Ritodrine, also known as 4-hydroxy-β-hydroxy-N-(4-hydroxyphenylethyl)amphetamine or as N-(4-hydroxyphenylethyl)-4-hydroxynorephedrine, is a substituted phenethylamine and amphetamine derivative. The experimental log P of ritodrine is 2.4 and its predicted ranges from 1.53 to 2.3.

History Ritodrine was first approved for medical use in the United States in 1984.

Society and culture

Names Ritodrine is the generic name of the drug and its INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name, BANTooltip British Approved Name, and DCFTooltip Dénomination Commune Française. In the case of the hydrochloride salt, its generic name is ritodrine hydrochloride and this is its USANTooltip United States Adopted Name and BANMTooltip British Approved Name. It is also known by its developmental code name DU-21220. The drug has been sold under brand names including Pre-Par, Utopar, and Yutopar, among others.

See also Hexoprenaline Isoxsuprine Terbutaline Bedoradrine

References

Illustrations

Worked examples

Example 1 — a first encounter with Ritodrine

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

In research: Ritodrine 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 Ritodrine 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: Ritodrine is common in secondary-school and first-year university syllabi. It links to neighbouring topics 4-Hydroxyphenyl compounds, Beta-Hydroxyamphetamines, Beta2-adrenergic agonists, so understanding it makes those chapters shorter.
In everyday life: Look for Ritodrine 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 Ritodrine in 20 minutes

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

Frequently asked questions

What is Ritodrine in simple terms?

Ritodrine, formerly sold under the brand name Yutopar among others, is a tocolytic drug used to stop premature labor. It was withdrawn from the US market, according to the FDA Orange Book.

Why does Ritodrine 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 Ritodrine?

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 Ritodrine.