Hydrocortisone

Key takeaways

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

Reference excerpt

Hydrocortisone is the name for the hormone cortisol when supplied as a medication. It is a corticosteroid and works as an anti-inflammatory and by immune suppression. Uses include conditions such as adrenocortical insufficiency, adrenogenital syndrome, high blood calcium, thyroiditis, rheumatoid arthritis, dermatitis, asthma, and COPD. It is the treatment of choice for adrenocortical insufficiency. It can be given by mouth, topically, rectally or by injection. Stopping treatment after long-term use should be done slowly. Common side effects may include mood changes, increased appetite, hyperglycemia, hypertension, and edema (swelling). With long-term use, common side effects include osteoporosis, adrenal insufficiency, upset stomach, physical weakness, easy bruising, and candidiasis (yeast infections). It is unclear if it is safe for use during pregnancy. Hydrocortisone was patented in 1936 and approved for medical use in 1941. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2023, it was the 182nd most commonly prescribed medication in the United States, with more than 2 million prescriptions.

Medical uses Hydrocortisone is the pharmaceutical term for cortisol used in oral administration, intravenous injection, or topical application. It is used as an immunosuppressive drug, given by injection in the treatment of severe allergic reactions such as anaphylaxis and angioedema, in place of prednisolone in patients needing steroid treatment but unable to take oral medication, and perioperatively in patients on long-term steroid treatment to prevent an adrenal crisis. It may also be injected into inflamed joints resulting from diseases such as gout. It may be used topically for allergic rashes, eczema, psoriasis, itching, and other inflammatory skin conditions. Topical hydrocortisone creams and ointments are available in most countries without prescription in strengths ranging from 0.05% to 2.5% (depending on local regulations) with stronger forms available by prescription only. It may also be used rectally in suppositories to relieve the swelling, itch, and irritation in hemorrhoids. It may be used as an acetate form (hydrocortisone acetate), which has slightly different pharmacokinetics and pharmacodynamics.

Side effects Side effects of hydrocortisone include hypertension, salt and water retention, hypokalemia, adrenal suppression, immunosuppression, increased risk of infections and infectious reactivation, Cushingoid symptoms, and neuropsychiatric symptoms such as depression, among many others. The side effects of hydrocortisone are dose-dependent, with many of them occurring only at higher doses. Hydrocortisone has been found to suppress rapid eye movement sleep (REM sleep) and to enhance slow wave sleep (SWS). In addition, it has been found to increase nighttime awakenings and time spent awake. The effects of hydrocortisone on sleep may be dose-dependent and different or even opposite at low versus high doses. It is thought that the glucocorticoid activity of hydrocortisone is responsible for REM sleep suppression, while its mineralocorticoid activity mediates its SWS enhancement.

Pharmacology

Pharmacodynamics Hydrocortisone is a corticosteroid, acting specifically as both a glucocorticoid and as a mineralocorticoid. That is, it is an agonist of the glucocorticoid and mineralocorticoid receptors. Hydrocortisone has low potency relative to synthetic corticosteroids. Compared to hydrocortisone, prednisolone is about 4 times as potent and dexamethasone about 40 times as potent in terms of anti-inflammatory effect. Prednisolone can also be used as cortisol replacement, and at replacement dose levels (rather than anti-inflammatory levels), prednisolone is about 8 times more potent than cortisol. The equivalent doses and relative potencies of hydrocortisone compared to various other synthetic corticosteroids have also been reviewed and summarized. The endogenous production rate of cortisol is approximately 5.7 to 9.9 mg/m2 per day, which corresponds to an oral hydrocortisone dose of approximately 15 to 20 mg/day (for a 70-kg person). One review described daily cortisol production of 10 mg in healthy volunteers and reported that daily cortisol production could increase up to 400 mg in conditions of severe stress (e.g., surgery). The total and/or free concentrations of cortisol/hydrocortisone required for various glucocorticoid effects have been determined. In addition to its corticosteroid receptor agonism, hydrocortisone has been reported to be a highly potent biphasic regulator of the GABAA receptor, acting as a positive allosteric modulator at low concentrations (1–10 pM) and as a negative allosteric modulator at high concentrations (10–1,000 nM).

Pharmacokinetics

Absorption The bioavailability of oral hydrocortisone is about 96% ± 20% (SD). The pharmacokinetics of hydrocortisone are non-linear. The peak level of oral hydrocortisone is 15.3 ± 2.9 (SD) μg/L per 1 mg dose. The time to peak concentrations of oral hydrocortisone is 1.2 ± 0.4 (SD) hours. The topical percutaneous absorption of hydrocortisone varies widely depending on experimental circumstances and has been reported to range from 0.5 to 14.9% in different studies. Some skin application sites, like the scrotum and vulva, absorb hydrocortisone much more efficiently than other application sites, like the forearm. In one study, the amount of hydrocortisone absorbed ranged from 0.2% to 36.2% depending on the application site, with the ball of the foot having the lowest absorption and the scrotum having the highest absorption. The absorption of hydrocortisone by the vulva has ranged from 4.4 to 8.1%, relative to 1.3 to 2.8% for the arm, in different studies and subjects.

Distribution Most cortisol in the blood (all but about 4%) is bound to proteins, including corticosteroid binding globulin (CBG) and serum albumin. A pharmacokinetic review stated that 92% ± 2% (SD) (92–93%) of hydrocortisone is plasma protein-bound. Free cortisol passes easily through cellular membranes. Inside cells it interacts with corticosteroid receptors.

Metabolism Hydrocortisone is metabolized by 11β-hydroxysteroid dehydrogenases (11β-HSDs) into cortisone, an inactive metabolite. It is additionally 5α-, 5β-, and 3α-reduced into dihydrocortisols, dihydrocortisones, tetrahydrocortisols, and tetrahydrocortisones.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Hydrocortisone

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

In research: Hydrocortisone 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 Hydrocortisone 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: Hydrocortisone is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alcohols, Antipruritics, CYP3A4 inducers, so understanding it makes those chapters shorter.
In everyday life: Look for Hydrocortisone 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.

How to study Hydrocortisone in 20 minutes

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

Frequently asked questions

What is Hydrocortisone in simple terms?

Hydrocortisone is the name for the hormone cortisol when supplied as a medication. It is a corticosteroid and works as an anti-inflammatory and by immune suppression.

Why does Hydrocortisone 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 Hydrocortisone?

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 Hydrocortisone.