chemistry

Losartan

Losartan 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 Losartan rather than just read about it. In short: Losartan, sold under the brand name Cozaar among others, is a medication used to treat high blood pressure (hypertension). It is in the angiotensin receptor blocker (ARB) family of medication, and is considered protective of the kidneys.

Key takeaways

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

Reference excerpt

Losartan, sold under the brand name Cozaar among others, is a medication used to treat high blood pressure (hypertension). It is in the angiotensin receptor blocker (ARB) family of medication, and is considered protective of the kidneys. Besides hypertension, it is also used in diabetic kidney disease, heart failure, and left ventricular enlargement. It comes as a tablet that is taken by mouth. It may be used alone or in addition to other blood pressure medication. Up to six weeks may be required for the full effects to occur. Common adverse effects include muscle cramps, stuffy nose, dizziness, cough, high blood potassium, and anemia. Severe adverse effects may include angioedema, low blood pressure, and kidney problems. Use during pregnancy may result in harm to the baby. Use is not recommended during breastfeeding. It works by blocking angiotensin II. Losartan was patented in 1986, and approved for medical use in the United States in 1995. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2023, it was the eighth most commonly prescribed medication in the US, with more than 56 million prescriptions. A version combined with hydrochlorothiazide as a diuretic is available which, in 2023, was the 65th most commonly prescribed medication in the United States, with more than 9 million prescriptions.

Chemistry Losartan potassium is chemically described as 2-butyl-4-chloro-1-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt. Its empirical formula is C22H23ClN6O, and its molecular weight is 422.9. Losartan is generally marketed as the (basic) potassium salt of the aromatized negatively charged tetrazole, called "losartan potassium". The molecule has an extended biphenyl group with a tetrazole which is being used in place of the carboxylic acid as a bioisostere.

Medical uses Losartan is used for hypertension, including in people with left ventricular hypertrophy (enlarged heart muscle), and kidney dysfunction among type II diabetics. It may also delay progression of diabetic nephropathy. It is a suitable pharmacological agent for the reduction of kidney (renal) disease progression in patients with type 2 diabetes, hypertension, and microalbuminuria (>30 mg/24 hours) or proteinuria (>900 mg/24 hours). Although evidence shows calcium channel blockers and thiazide-type diuretics are preferred first-line treatments for most people (due to both efficacy and cost), an angiotensin II receptor antagonist such as losartan is recommended as first-line treatment in people under the age of 55 who cannot tolerate an ACE inhibitor. One study demonstrated losartan was superior to atenolol in the primary prevention of adverse cardiovascular events (myocardial infarction or stroke), with a reduction in cardiovascular morbidity and mortality for a comparable reduction in blood pressure. The maximal effects on blood pressure usually occur within 3–6 weeks of starting losartan.

Adverse effects The most common adverse effects for losartan in adults are upper respiratory infections, dizziness, and back pain. People with type 2 diabetes and kidney disease may experience diarrhea, fatigue, low blood pressure, low blood glucose, elevated potassium, chest pain, or allergic reaction. Losartan should not be taken by people who are diabetic and taking aliskiren. Anemia may occur, due to inhibition of the renin–angiotensin system. As with other angiotensin receptor blockers, losartan may injure the liver, although this effect appears to be rare. Electrolyte imbalances may occur in people with kidney problems who take losartan. Adverse outcomes do not differ by sex, age, or race.

Pregnancy In October 2014, the US Food and Drug Administration (FDA) issued a black box warning that losartan can cause fetal toxicity and should be discontinued as soon as pregnancy is detected. Using losartan while pregnant could result in fetal injury or death.

Overdose Overdosing would most likely result in decreased blood pressure, which could manifest as an increased heart rate, dizziness, feeling lightheaded, or loss of consciousness. Mice studies showed that lethality occurred at about 44 to 170 times the maximum recommended dose after the mice weights were taken into account.

Interactions Losartan may have adverse interactions with phenobarbital, rifampin, or fluconazole, possibly inhibiting its blood pressure-lowering effects.

Contamination

Between November 2018 and September 2019, the FDA announced multiple recalls of tablets containing losartan by Sandoz, Torrent Pharmaceuticals, Hetero Labs, Camber Pharmaceuticals, Legacy Pharmaceutical Packaging, Teva Pharmaceuticals, Vivimed Life Sciences, and Macleods Pharmaceutical Limited due to detection of one of the possible carcinogens N-nitrosodiethylamine, N-methylnitrosobutyric acid, or N-nitroso-N-methyl-4-aminobutyric acid in the active pharmaceutical ingredient (API).

Mechanism of action

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Losartan

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

In research: Losartan 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 Losartan 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: Losartan is common in secondary-school and first-year university syllabi. It links to neighbouring topics 5-(2-phenylphenyl)-2H-tetrazole derivatives, Butyl compounds, Chloroarenes, so understanding it makes those chapters shorter.
In everyday life: Look for Losartan 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 Losartan in 20 minutes

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

Frequently asked questions

What is Losartan in simple terms?

Why does Losartan 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 Losartan?

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 Losartan.