The Untold Story of Panadol: How Paracetamol Became the World’s Painkiller

You have almost certainly swallowed it. A fever at 2am, a throbbing tooth, the dull ache after a long day at a screen. In Pakistan the word people reach for is not “paracetamol” or “acetaminophen”. They say Panadol, the way some say “Surf” for any detergent. The brand has become the drug.

What almost nobody knows is how strange the road to that little white tablet really was. Paracetamol spent decades sitting unused on a shelf while doctors handed out a cousin compound that was slowly poisoning people. The history of panadol is a story of a near miss, a lucky piece of detective work, and a medicine so ordinary that we forget it was once a genuine discovery.

A chemical born in 1877 that nobody wanted

The first person to make paracetamol was an American chemist named Harmon Northrop Morse, working in Baltimore in 1877. He produced it in the lab and described it in a paper. Then he moved on. There was no clinical trial, no pharmacy shelf, no patient. The compound was a curiosity, one of thousands of molecules being cooked up as the synthetic chemistry boom took off in Europe and the United States.

This was normal for the era. Chemists made new substances faster than anyone could test what they did inside a body. Many promising molecules were filed away in journals and simply forgotten, waiting for someone to ask the right question. Paracetamol’s moment would not come for another two generations, and when it did, it arrived through the back door rather than through any deliberate search for a better painkiller.

The dye factories that became drug factories

The painkillers of the late 1800s came out of the same German and British factories that made fabric dyes. Coal tar was the raw material for both. Out of that industry came two fever-reducing compounds that doctors actually used: acetanilide (sold as Antifebrin from 1886) and later phenacetin, which became one of the most widely used painkillers in the world for decades.

Both worked. People with fever cooled down, people in pain felt relief. That was enough for the time. The problem was hiding in the chemistry, and it would take fifty years to surface.

The hidden danger in the old painkillers

The most uncomfortable part of the history of panadol is what came before it. Acetanilide had a nasty habit. In some people it turned the iron in their blood into a form that could not carry oxygen, a condition called methaemoglobinaemia. Lips and fingertips would go blue. Phenacetin had its own slow problem: heavy long-term use was eventually linked to kidney damage and, in the worst cases, kidney cancer. By the 1970s and 1980s many countries pulled phenacetin off the market entirely.

So here is the irony at the heart of this story. For decades, people were taking drugs that worked partly because their bodies were quietly converting them into something else. That something else was paracetamol.

The active painkiller people had been swallowing for fifty years was a metabolite they had never heard of, masked inside a drug that was harming them.

Two scientists who followed the trail

In 1948, two pharmacologists at the New York City Department of Health, Bernard Brodie and Julius Axelrod, set out to understand why acetanilide caused the blood problem. They tracked what the body did to it. They found that acetanilide broke down into two things: one piece caused the methaemoglobinaemia, and the other piece, paracetamol, was doing the actual pain and fever work without the toxic side effect.

Their conclusion was elegant. If you skipped the parent drug and gave paracetamol directly, you got the benefit and dropped the danger. It was the kind of insight that looks obvious only in hindsight. For half a century the medical world had been treating the wrapper as the gift. Axelrod went on to win a Nobel Prize years later for separate work on neurotransmitters, but this early study quietly rewrote the future of the medicine cabinet.

From discovery to the Panadol brand

The next chapter in the history of panadol is about commerce, not chemistry. Knowing a compound is safe and useful is not the same as selling it. That step took the 1950s.

Paracetamol reached the market for general use around 1953 to 1955. In the United States it appeared as Tylenol for children in 1955. In Britain, the firm Frederick Stearns and Company, then a subsidiary of Sterling Drug, introduced Panadol in 1956. It was sold at first to doctors rather than over the counter, marketed as gentler on the stomach than aspirin.

Why the same drug has so many names

This trips people up constantly. Paracetamol and acetaminophen are the same molecule. The two words are just different shortenings of the chemical name (para-acetylaminophenol). “Paracetamol” is the standard name across the UK, Pakistan, India, Australia and most of the world. “Acetaminophen” is the name used in the United States and Japan.

On top of the generic name sit the brands. Panadol, Tylenol and Calpol (the children’s syrup) are all the identical active ingredient. The brand on the box does not change the chemistry inside it.

The timeline at a glance

Year	What happened
1877	Harmon Northrop Morse first synthesises paracetamol in Baltimore. It is ignored.
1886	Acetanilide enters use as Antifebrin, a fever reducer.
1890s	Phenacetin becomes a leading painkiller across Europe.
1948	Brodie and Axelrod show paracetamol is the safe active metabolite.
1953-1955	Paracetamol reaches the market for general use; Tylenol launches for children in the US.
1956	Frederick Stearns introduces Panadol in the UK.
1980s	Phenacetin banned in many countries over kidney harm.
2022	The Panadol brand sits within GSK’s consumer arm, spun off as Haleon.

The brand has changed hands over the years. The consumer health business that owns Panadol was part of GlaxoSmithKline (GSK) and in 2022 was spun off into a standalone company called Haleon. The tablet in your drawer has a longer corporate lineage than most family businesses.

How paracetamol actually works (and what we still don’t know)

Here is something that surprises people. After nearly 150 years, we still cannot fully explain how paracetamol relieves pain. We know what it does. We are fuzzy on the precise machinery.

What is reasonably clear is that it works mainly in the central nervous system, the brain and spinal cord, rather than at the site of an injury. This is the opposite of how anti-inflammatory drugs work, and it explains a lot about paracetamol’s strengths and limits. If you want the bigger picture of how the body generates and processes discomfort, our piece on the science of pain goes deeper.

Weak on inflammation, good on the brain’s pain signals

Drugs like ibuprofen and aspirin block enzymes called COX-1 and COX-2 strongly, throughout the body, including at swollen joints and torn muscle. That is why they reduce inflammation. Paracetamol touches the COX system only weakly and mostly inside the brain, which is why it brings down pain and fever but does little for the swelling of, say, a sprained ankle.

The endocannabinoid and TRPV1 clues

Newer research points to paracetamol’s breakdown products acting on the body’s own endocannabinoid system and on a receptor called TRPV1, the same receptor that responds to the heat of chillies. One metabolite, AM404, seems to be part of the pain-relieving effect. This is genuinely active research, not settled fact, so treat it as a promising direction rather than the final answer. The honest position, stated plainly by sources including the Cleveland Clinic and others, is that the full mechanism is still being worked out.

Why it lowers fever

Fever is set by the brain’s thermostat in the hypothalamus, which is pushed up by chemical signals during infection. Paracetamol acts on that thermostat to bring the set point back down, which is why it is a workhorse for fevers. If you have ever wondered why your body bothers to run a fever in the first place, we explain the logic in why we get fever.

Why it is sold over the counter

Most painkillers strong enough to matter need a prescription. Paracetamol does not, in nearly every country. There is a solid reason for that.

A clean safety profile at the correct dose

At normal doses, paracetamol is gentle. It does not irritate the stomach lining, it does not cause the gut bleeding that long-term NSAID use can, and it is generally safe in pregnancy and for young children when dosed correctly. The NHS lists it as suitable for most people, including during pregnancy, which is a high bar for any drug.

That combination, real relief plus a clean safety record at the right dose, is exactly why regulators allow it on supermarket shelves rather than behind a pharmacist’s counter.

Paracetamol versus ibuprofen versus aspirin

People mix these up all the time, often because all three live in the same drawer. They are not interchangeable. A quick comparison helps.

	Paracetamol	Ibuprofen	Aspirin
Drug class	Analgesic / antipyretic	NSAID	NSAID
Reduces inflammation?	No, barely	Yes	Yes
Easy on the stomach?	Yes	Can irritate / bleed	Can irritate / bleed
Main risk in overdose	Liver damage	Kidney and gut	Bleeding, ringing ears
Safe in pregnancy?	Generally yes	Avoid, esp. late	Avoid
Also a blood thinner?	No	Mild	Yes, used for the heart

The serious risk nobody talks about enough

The same property that makes paracetamol safe also makes its overdose deceptive. There is no immediate dramatic warning. Someone can take far too much, feel almost normal for a day, and only fall seriously ill once the liver has already been harmed.

Why the liver is the target

Your liver breaks paracetamol down. A small fraction becomes a toxic byproduct called NAPQI, which the liver normally neutralises using a protective molecule called glutathione. At normal doses there is plenty of glutathione. In an overdose, the supply runs out, and the leftover NAPQI starts destroying liver cells. This is why paracetamol overdose is one of the leading causes of acute liver failure in countries like the UK and the United States, a fact documented across the medical literature on PubMed Central.

The dose ceiling, in plain numbers

For most healthy adults the maximum is 4 grams (4000 mg) in 24 hours, which usually means no more than 8 standard 500 mg tablets across the whole day, spaced out. The Mayo Clinic and other authorities set this ceiling clearly. People with liver disease, those who drink heavily, and the very small need less. The danger often comes not from one obvious overdose but from doubling up: taking Panadol plus a cold-and-flu sachet that also contains paracetamol, without realising.

The antidote that makes timing everything

There is a treatment, a drug called N-acetylcysteine, that restores the liver’s glutathione and can prevent the damage. It is highly effective, but only if given early, ideally within the first several hours. That is why the message from every poison centre is the same: do not wait to see if symptoms appear. By the time someone with a serious paracetamol overdose feels unwell, the window for the easiest rescue may be closing.

Paracetamol in Pakistan

Few drugs are as woven into Pakistani daily life as Panadol. It is the default answer to fever in a country where fever is common, from seasonal flu to dengue to typhoid. Walk into any home and you will likely find a strip of it in a kitchen drawer or a handbag.

A household name, and a household risk

Because it is so familiar, people tend to treat it as harmless. That casual trust is the danger. Self-medicating across multiple combination products, or giving an adult dose to a child, is exactly the pattern that leads to harm. The drug deserves respect, not fear. Pakistan also carries a heavy burden of liver disease from hepatitis, which means many livers are already under strain before any tablet is taken. Our explainer on hepatitis C in Pakistan covers why that matters for any drug the liver has to process.

The shortage episodes

Pakistan has lived through repeated Panadol and paracetamol shortages, where the cheap, price-controlled tablet vanished from pharmacy shelves for stretches at a time. Manufacturers have argued that the government-fixed price sat below the cost of imported raw material, so production stalled. For a medicine this essential, a shortage is not a minor inconvenience. It pushes people toward unfamiliar substitutes or unsafe doses of whatever they can find. It is a reminder that the economics behind a 5 rupee tablet can matter as much as the chemistry inside it.

Overuse of any drug also feeds a wider problem in Pakistan, the casual culture of self-medication. While paracetamol is not an antibiotic, the same habit that has people popping pills without advice is part of what drives antibiotic resistance in Pakistan, one of the country’s most serious slow-burning health threats.

What the history of panadol teaches us

The history of panadol is really the history of a happy accident that took a century to be understood. A molecule made and forgotten in 1877. A pair of curious scientists in 1948 who asked why an old drug was making blood go blue. A British brand in 1956 that turned the answer into a tablet you can buy for pocket change.

Told end to end, the history of panadol is a good reminder that “ordinary” medicines are not simple. Paracetamol is one of the most used drugs on Earth, listed by the World Health Organization among essential medicines, and we are still mapping how it works. Used correctly, it is a small miracle. Used carelessly, it is one of the most common causes of preventable liver failure. Both things are true of the same white pill.

Frequently asked questions

Is Panadol the same as paracetamol?

Yes. Panadol is a brand name for paracetamol, which is the generic chemical. The active ingredient inside Panadol, Calpol and many other boxes is identical paracetamol. In the United States the same chemical is called acetaminophen and sold as Tylenol. The brand affects the price and the packaging, not the drug itself.

Who actually invented paracetamol?

It was first synthesised by the American chemist Harmon Northrop Morse in 1877, but he never used it as a medicine. The two people who turned it into a real drug were Bernard Brodie and Julius Axelrod, who in 1948 proved it was the safe active part of older painkillers. The Panadol brand came later, in 1956.

Why does paracetamol not help with swelling?

Because it works mainly in the brain and spinal cord, not at the injury itself. Anti-inflammatory drugs like ibuprofen block COX enzymes strongly throughout the body, including swollen tissue. Paracetamol touches that system only weakly and mostly in the central nervous system, so it eases pain and fever but does little for inflammation.

How much paracetamol is too much?

For most healthy adults the ceiling is 4 grams, or 4000 mg, in 24 hours, which is usually no more than eight 500 mg tablets spread across the day. People with liver disease or heavy alcohol use need less. The biggest real-world risk is accidentally doubling up by taking Panadol alongside a cold-and-flu remedy that also contains paracetamol.

What makes paracetamol overdose so dangerous?

The liver turns a small amount of paracetamol into a toxic byproduct. In overdose, the liver’s protective reserves run out and that byproduct kills liver cells. The deceptive part is timing: a person can feel fine for a day before serious illness appears, which is why it is a leading cause of acute liver failure in several countries.

Is paracetamol safe during pregnancy?

It is generally considered the preferred painkiller in pregnancy and is listed as suitable by health bodies including the NHS, when taken at the normal dose for the shortest time needed. Anti-inflammatory drugs like ibuprofen are usually avoided, especially later in pregnancy. As with any medicine in pregnancy, it is sensible to check with a doctor first.

Why does Pakistan keep running short of Panadol?

Paracetamol is price-controlled in Pakistan, and during shortages manufacturers have said the fixed retail price fell below the cost of imported raw materials, so they cut production. Because the drug is so widely used for fever, even a short gap on pharmacy shelves pushes people toward unfamiliar substitutes or unsafe doses.