biology

Isosorbide dinitrate

Isosorbide dinitrate is a biology 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 Isosorbide dinitrate rather than just read about it. In short: Isosorbide dinitrate is a medication used for heart failure, esophageal spasms, and to treat and prevent angina pectoris. It has been found to be particularly useful in heart failure due to systolic dysfunction together with hydralazine.

Key takeaways

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

Reference excerpt

Isosorbide dinitrate is a medication used for heart failure, esophageal spasms, and to treat and prevent angina pectoris. It has been found to be particularly useful in heart failure due to systolic dysfunction together with hydralazine. It is taken by mouth or under the tongue. Common side effects include headache, lightheadedness with standing, and blurred vision. Severe side effects include low blood pressure. It is unclear if use in pregnancy is safe for the baby. It should not be used together with PDE5 Inhibitors. Isosorbide dinitrate is in the nitrate family of medications and works by dilating blood vessels. Isosorbide dinitrate was first written about in 1939. It is on the World Health Organization's List of Essential Medicines. Isosorbide dinitrate is available as a generic medication. A long-acting form exists. In 2023, isosorbide was the 125th most commonly prescribed medication in the United States, with more than 5 million prescriptions.

Medical uses It is used for angina, in addition to other medications for congestive heart failure, and for esophageal spasms. It is available as an oral tablet both in extended release and slow release. The onset of action for Isosorbide Dinitrate is thirty minutes and the onset of action for oral extended release is 12–24 hours. Long-acting nitrates can be more useful as they are generally more effective and stable in the short term.

Side effects

Tolerance After long-term use for treating chronic conditions, tolerance may develop in patients, reducing its effectiveness. The mechanisms of nitrate tolerance have been thoroughly investigated in the last 30 years and several hypotheses have been proposed. These include:

Impaired biotransformation of isosorbide dinitrate to its active principle NO (or a NO-related species) Neurohormonal activation, causing sympathetic activation and release of vasoconstrictors such as endothelin and angiotensin II which counteract the vasodilation induced by isosorbide dinitrate Plasma volume expansion The oxidative stress hypothesis The last hypothesis might represent a unifying hypothesis, and an isosorbide dinitrate-induced inappropriate production of oxygen free radicals might induce a number of abnormalities which include the ones described above. Furthermore, nitrate tolerance is shown to be associated with vascular abnormalities which have the potential to worsen patients prognosis: these include endothelial and autonomic dysfunction.

Mechanism of action Similar to other nitrites and organic nitrates, isosorbide dinitrate is converted to nitric oxide (NO), an active intermediate compound which activates the enzyme guanylate cyclase (atrial natriuretic peptide receptor A). This stimulates the synthesis of cyclic guanosine 3',5'-monophosphate (cGMP) which then activates a series of protein kinase-dependent phosphorylations in the smooth muscle cells, eventually resulting in the dephosphorylation of the myosin light chain of the smooth muscle fiber. The subsequent sequestration of calcium ions results in the relaxation of the smooth muscle cells and vasodilation.

Society and culture Isosorbide dinitrate is sold in the US under the brand names Dilatrate-SR by Schwarz and Isordil by Valeant, according to FDA Orange Book. It is sold under the trade name Isoket in the United Kingdom, Argentina, and Hong Kong. It is also a component of BiDil.

References

Illustrations

Worked examples

Example 1 — a first encounter with Isosorbide dinitrate

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

In research: Isosorbide dinitrate appears in biology 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 Isosorbide dinitrate 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: Isosorbide dinitrate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antianginals, Drugs developed by Pfizer, Drugs developed by Wyeth, so understanding it makes those chapters shorter.
In everyday life: Look for Isosorbide dinitrate 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 Isosorbide dinitrate in 20 minutes

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

Frequently asked questions

What is Isosorbide dinitrate in simple terms?

Why does Isosorbide dinitrate matter?

Because it connects several biology 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 Isosorbide dinitrate?

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 Isosorbide dinitrate.