science

Paricalcitol

Paricalcitol 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 Paricalcitol rather than just read about it. In short: Paricalcitol (chemically it is 19-nor-1,25-(OH)2-vitamin D2. Marketed by Abbott Laboratories under the trade name Zemplar) is a drug used for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic kidney failure.

Key takeaways

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

Reference excerpt

Paricalcitol (chemically it is 19-nor-1,25-(OH)2-vitamin D2. Marketed by Abbott Laboratories under the trade name Zemplar) is a drug used for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic kidney failure. It is an analog of 1,25-dihydroxyergocalciferol, the active form of vitamin D2 (ergocalciferol). It was patented in 1989 and approved for medical use in 1998.

Medical uses Its primary use in medicine is in the treatment of secondary hyperparathyroidism associated with chronic kidney disease. However a 2016 systematic review did not find evidence sufficient to demonstrate an advantage of paricalcitol over non-selective vitamin D derivatives for this indication.

Adverse effects Adverse effects by frequency: Very common (>10% frequency):

Nausea Common (1-10% frequency):

Uncommon (0.1-1% frequency):

‡ These are adverse effects only seen in patients with grade 3 or 4 chronic kidney disease. † These are adverse effects only seen in patients with grade 5 chronic kidney disease.

Contraindications Contraindications include:

Vitamin D intoxication Hypercalcaemia Hypersensitivity to paricalcitol or any of its excipients whereas cautions include:

Impaired liver function It is also advised that physicians regularly monitor their patients' calcium and phosphorus levels.

Interactions Drugs that may interact with paricalcitol include:

Overdose Electrolyte abnormalities (e.g. hypercalcaemia and hyperphosphataemia) are common overdose symptoms. Treatment is mostly supportive, with particular attention being paid to correcting electrolyte anomalies and reducing intake of calcium in both the form of supplementation and diet. As it is so heavily bound to plasma proteins haemodialysis is unlikely to be helpful in cases of overdose. Early symptoms of overdose can include:

However, many of these symptoms are also indicative of kidney failure and hence may be masked by the patient's condition. Late symptoms of overdose include:

Mechanism of action

Like 1,25-dihydroxyergocalciferol, paricalcitol acts as an agonist at the vitamin D receptor and thereby lowers parathyroid hormone levels in the blood.

Pharmacokinetics The plasma concentration of paricalcitol decreases rapidly and log-linearly within two hours after initial intravenous administration. Therefore, it is not expected to accumulate with multiple dosing, since paricalcitol is usually given no more frequently than every other day (3 times per week).

References

Illustrations

Worked examples

Example 1 — a first encounter with Paricalcitol

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

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

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

Frequently asked questions

What is Paricalcitol in simple terms?

Why does Paricalcitol 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 Paricalcitol?

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 Paricalcitol.