If cortisone won a Nobel in 1950, why does my bottle say prednisolone 5 mg?
September 1948, before anyone said prednisolone
The first human page is an injection, not a 5 mg oral chip.
Philip Hench had watched rheumatoid joints ease in pregnancy and in jaundice. He guessed an adrenal 'substance X'. Edward Kendall already had Compound E on the bench from 1930s adrenal isolates. Merck's Lewis Sarett had made enough synthetic material to try. On 21 September 1948, Charles Slocumb gave a 29-year-old woman at Mayo 100 mg of Compound E intramuscularly. Within three days she was markedly better. They later named the compound cortisone.
That was the first drug that shut inflammation itself down, not just the pain. Word left Rochester faster than a monograph. I still write in the margin: the walk came first, the chemistry lecture second. Anyone who starts this story with a modern 5 mg tablet has skipped the shot that made the class famous.
Hench did not invent a receptor theory that morning. He tested a hunch with a scarce crystal. The hunch held. The hangover - oedema, pressure, potassium loss - arrived as soon as doses stayed high. That hangover is why the 5 mg prednisolone tablet exists.
A Nobel in 1950, while the salt bill was still being written
The 1950 Nobel Prize in Physiology or Medicine went to Hench and Kendall at Mayo and Tadeus Reichstein in Switzerland for adrenal-cortex hormones, their structures, and their effects. Two years after the first ward shot. Unusual speed. The committee already knew the benefit and the toxicity shared one source: flooding a person with a systemic hormone does more than quiet a joint.
I file the Nobel as a date, not a halo. Cortisone earned the medal. It did not earn a free pass for lifelong high-dose use. Clinicians who lived through the early 1950s watched faces round and ankles swell while the joints improved. Enthusiasm and alarm grew on the same ward round. The 1950 Nobel summary still reads as a chemistry prize. The margin on this desk adds the fluid chart.
Reichstein's isolation work and Kendall's structures made the later edit possible. You cannot add a double bond to a molecule you have not drawn. That is the only reason I keep the Swiss name on a prednisolone 5 mg page.
Cortisone worked. The mineralocorticoid overlap capped the dose
Two adrenal jobs live in one cortex: sugar-and-immune, and salt-and-potassium.
Glucocorticoids move glucose and turn down inflammatory genes. Mineralocorticoids, aldosterone first, hold sodium and dump potassium. Cortisone and hydrocortisone do both. At the anti-inflammatory doses Hench needed, patients retained fluid, blood pressure climbed, and potassium fell. You could undertreat the joints or overload the circulation. That was the daily choice, not a footnote.
Once the structures were known, chemists asked a narrower question: keep the glucocorticoid punch, strip the salt. Hydrocortisone (cortisol) is the native ligand. Cortisone is one oxidation step away and still carries a mineralocorticoid tax. Neither was a comfortable once-daily outpatient tablet at inflammatory doses. The 5 mg prednisolone chip is the answer that stuck.
I still meet readers who think 'steroid' means one salt-heavy 1950s injection. Write the class split in the margin before you praise the modern tablet. The prednisolone 5 mg medicine note keeps the receptor page. This file keeps the reason the tablet looks the way it does.
One double bond, a bacterium, and a 1955 paper
Arthur Nobile and colleagues at Schering in Bloomfield, New Jersey, published a microbiological 1,2-dehydrogenation of ring A in 1955. Corynebacterium simplex did the oxidation more cleanly than the chemical routes then on the bench. The products were first called metacortandracin and metacortandralone. The names that stuck are prednisone and prednisolone.
The edit raised glucocorticoid potency about three- to fourfold versus cortisone or cortisol and cut mineralocorticoid activity sharply. A smaller milligram could do the anti-inflammatory job with less oedema. That is the whole industrial reason a prednisolone 5 mg tablet became the outpatient unit. Not marketing. Arithmetic on salt versus punch.
Bunim's 1955 rheumatoid series on the new compounds read like a second Mayo moment - joints moving again, this time on an oral tablet that did not flood the ankles as fast. I write 'second moment' in pencil. The first moment was 1948. The second was a usable daily dose. Peer-line that distinction before you call prednisolone a discovery. It is an edit of a discovery.
Why the blotter still files 5 mg, not 20
Equivalence cards print hydrocortisone 20 mg as the cortisol-like reference and prednisolone 5 mg as the intermediate workhorse. Same anti-inflammatory idea, one-quarter the milligram, far less salt. Once-daily morning dosing became realistic because the biological window sits in the 12-36 hour band, not the short 8-12 hour cortisol band that wants split doses.
I keep 5 mg as the SERP lock on this site because that is the labelled chip most desks still count. Inflammatory bursts use many chips. Physiologic replacement lives near one chip. The number is not a slogan. It is the unit that survived the 1950s edit. If a page talks prednisolone without naming 5 mg, the reader cannot place the dose on a chart.
Later cousins - methylprednisolone, dexamethasone - tuned potency and duration further. They did not retire the 5 mg prednisolone tablet. Rheumatology, chest, dermatology, and transplant still reach for it when they want an oral glucocorticoid that a patient can take at breakfast. That continuity is the development story, not a brand timeline.
Prednisone and prednisolone: near twins, not a worldwide 1:1 law
The names swap in speech. The bottles do not always swap by the milligram stamp.
| Margin item | Prednisone | Prednisolone 5 mg |
|---|---|---|
| What it is | 11-keto prodrug | Active 11-OH ligand |
| Needs a working liver | Yes, 11-beta-HSD1 | No conversion step |
| US ward habit | Common oral script | Used, often as liquid or if liver is frail |
| UK / AU / NZ habit | Uncommon on the chart | Usual oral glucocorticoid |
| Healthy-liver mg card | Often printed 1:1 with prednisolone | Reference 5 mg chip |
| Do not assume | A foreign 5 mg bottle is the same drug | A US prednisone 5 mg is a global twin |
Prednisone is the 11-keto prodrug. A healthy liver reduces it to prednisolone, the 11-hydroxy ligand that actually sits on the glucocorticoid receptor. US conversion cards often print 5 mg prednisone = 5 mg prednisolone. That is a healthy-liver approximation, and it is the line most American wards use. It is not a statute that travels.
The United Kingdom, Ireland, Australia, and New Zealand write prednisolone as the oral workhorse. Prednisone is uncommon on those charts. Several EU and Japanese desks stock different preferred chips and different labelled strengths. Severe hepatic disease can stall the conversion, so the active tablet is the safer pick there even if a US card says 1:1. A traveller matching '5 mg' on two bottles may be matching a strength, not proving the same active molecule in the same body.
I do not invent a secret 4:5 national ratio. I refuse the other error too: telling every reader the names are interchangeable everywhere because a US table said so. Ask the local product and the liver, then the milligram. The table below is a margin, not a passport.
What the 1955 tablet unlocked - and what it did not cure
1930s
Kendall and Reichstein isolate and draw adrenal-cortex steroids. Compound E sits on a bench before it has a ward.
1948
21 September: Slocumb injects Compound E at Mayo. The patient improves within days. Cortisone gets its name.
1950
Hench, Kendall, and Reichstein share the Nobel. Benefit and toxicity are already travelling together.
1955
Nobile's group publishes the microbial 1,2-dehydrogenation. Prednisone and prednisolone enter the clinic with more punch and less salt.
After 1955
The prednisolone 5 mg tablet becomes the outpatient unit. Specialties adopt it. Bone, infection, and HPA suppression join the margin.
Once a drier oral glucocorticoid existed, specialties borrowed it. Asthma flares, skin disease, nephritis, transplant rejection, autoimmune cytopenias, emergency airway oedema. Few classes crossed that many doors that fast. The 5 mg tablet made chronic outpatient steroid therapy possible. Possible is not the same as wise.
The same receptor that calms a joint also thins bone, raises glucose, and hushes the HPA axis if the course runs past about two weeks. Infection risk climbs because useful immunity is on the same switch. Those harms were mapped within a decade of the Nobel. None of them are modern surprises. The development story ends in a caution, not a parade.
For where the 5 mg chip still earns a burst, read the ward reviews of prednisolone 5 mg. For the stop rule, read the taper file before anyone bins the bottle. This page only explains how the chip got onto the blotter.
What I still pencil beside the 5 mg chip
Three holds stay in this history file. First: cortisone was the proof, prednisolone 5 mg is the usable edit. Do not flatten them into one fairy tale. Second: prednisone is a prodrug of prednisolone, and a US 1:1 card does not bind a UK or Japanese chart. Third: the power that walked the 1948 patient is the same power that suppresses cortisol, bone, and infection defence if the course never ends.
I file this as a development note, not a museum card. The chemistry is settled. The prescribing error that survives is treating the 5 mg tablet as a harmless vitamin because it is small and old. Small and old is why it is everywhere. Everywhere is why the taper and the infection question still belong in the same folder as the Nobel.
Helena peer-lines history pages the way she peer-lines doses: name the hold, then the milligram. If you came here to shop a bottle, you are in the wrong building. If you came to see why a 5 mg prednisolone tablet is not 1948 cortisone, this file is the margin.
Reader mail
Reader questions on this article
Answered by Dr. Helena Vasquez, PharmD · Clinical pharmacology & drug safety
Mail after the history note. Helena answered in the margin - teaching, not a script.
Cortisone proved a systemic hormone could shut inflammation down. It also held salt. At the doses that moved joints, ankles swelled and potassium fell. Schering's 1955 1,2-double bond made prednisolone: about four times the glucocorticoid punch, much less mineralocorticoid tax. The 5 mg tablet is that later unit, not cortisone with a new label. I still honour the Nobel. I do not pretend the 1948 injection is what you swallow at breakfast.
My US chart says prednisone 5 mg equals prednisolone 5 mg. A cousin in Manchester got prednisolone only. Who is right?
Both desks can be right and still not be a passport. A healthy liver converts prednisone to prednisolone, so many US cards print 1:1. The UK writes prednisolone as the oral workhorse and barely stocks prednisone. Severe liver disease can stall the conversion. Match the local product and the liver, not the milligram stamp on a traveller's photo. I will not bless a swap from this thread.
Was the first cortisone patient really walking in days, or is that ward folklore?
The Mayo record is specific. 21 September 1948, Compound E 100 mg intramuscularly, a young woman with crippling rheumatoid arthritis, marked improvement within three days. Hench had chased a pregnancy-and-jaundice clue for years before that shot. Folklore grew around a real morning. I file the date. I also file that the same patient class later taught us oedema and the need for a drier tablet.
Did a bacterium really manufacture a steroid people still take?
Corynebacterium simplex added the C1-C2 double bond more cleanly than 1950s glassware. Nobile's 1955 JACS note is the paper I keep. Microbial dehydrogenation is ordinary now. Then it was the step that made an oral, less salty glucocorticoid manufacturable. The 5 mg prednisolone chip on a modern blister is downstream of that fermentation, not of a plant extract.
Is prednisolone a natural hormone or a lab cousin?
Lab cousin of cortisol (hydrocortisone). One deliberate double bond. Same receptor family, stronger anti-inflammatory effect per milligram, less fluid retention. Because it is still a glucocorticoid, a course past about two weeks can hush your own cortisol. That is why the taper file exists. Natural-versus-synthetic is the wrong comfort. Receptor occupancy is the hold.
Are dexamethasone and methylprednisolone just later versions of the same 1955 trick?
Same scaffold, further edits - potency, duration, even less salt. Dexamethasone is far stronger milligram-for-milligram and almost mineralocorticoid-silent, which is why it shows up for brain oedema and single-dose croup. Methylprednisolone sits near 4 mg for a 5 mg prednisolone equivalent. They are descendants, not synonyms. Do not convert them by matching tablet counts.
Why did doctors turn cautious if the 1950s called this a miracle?
The miracle was real on a flare. Months and years then wrote the other ledger: bone loss, infection, high glucose, HPA suppression, cataracts. Efficacy did not vanish. Strategy changed - lowest dose, shortest time, a steroid-sparing plan if the disease is chronic. Caution is the inheritance, not a fashion. See the taper file on prednisolone 5 mg before anyone calls a long course harmless because the chip is small.
Can I treat a UK prednisolone 5 mg as the same as a US prednisone 5 mg on holiday?
Not from a photograph of two blisters. Healthy-liver US practice often treats them as equivalent. Holiday livers, holiday brands, and holiday labelled strengths are not the study that card was drawn from. Bring both names to a local clinician. I will not convert your suitcase from Aberdeen mail.
Where should I read the receptor and dose page after this history?
The medicine note for prednisolone 5 mg holds the receptor, the equivalence row, and the safety holds. This library page only explains how the chip was built. If you want service-by-service evidence, use the ward reviews. History is the left margin. It is not your taper.
General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.
Last Updated