Pethidine’s story starts in the late 1930s, when German chemists set out to synthesize new antispasmodics. By accident, they landed on a compound with powerful pain-relieving effects, which quickly caught the eye of doctors desperate for alternatives to morphine. In post-war clinics and hospitals, pethidine—often called meperidine in the United States—became the go-to option for pain relief. The timing aligned with the search for non-opioid painkillers, yet early experiences glossed over concerns about toxicity and dependence. Over the decades, clinicians found its relatively short action and unique side-effect profile both helpful and challenging, as pethidine replaced morphine in many obstetric suites yet brought new safety concerns to the fore.
Pethidine stands apart as a synthetic opioid, not derived from the poppy plant. Its reputation comes from ease of synthesis and a clinical profile promising less constipation and muscle spasm compared to morphine. Decades ago, it was among the few injectable narcotics available; as such, it found a place on every crash cart and delivery room shelf. The rush to use pethidine rarely slowed for a closer look at its byproducts—or its potential for dependence—until years of practical experience could point out its limitations.
Under harsh hospital lights, pethidine appears as white, crystalline powder with a faint bitter taste. Its molecular identity centers on a piperidine ring bearing an ethyl ester and a methylated nitrogen, C15H21NO2. With a melting point from 186°C to 189°C, it dissolves well in water and alcohol, ideal for formulations needing rapid absorption. The basic nitrogen atom ensures it binds quickly to opioid receptors, creating both promise and pitfalls in its use.
Any reputable supplier provides pethidine with clear labeling: chemical name (pethidine hydrochloride), dosage form (usually 50mg/mL ampoules for injection), and batch information for traceability. Storage instructions require a cool, dry place away from light, and expiration dates reflect concerns about both potency and breakdown products turning toxic. Regulations demand each shipment carries precise data for clinicians, pharmacists, and regulators to check against, reducing the risk of dosing errors or counterfeit shipments. The Drug Enforcement Administration and local health authorities rigorously monitor supply chains for compliance and public safety.
Synthesizing pethidine involves several well-characterized reactions. The starting material, benzyl cyanide, undergoes alkylation to add the piperidine ring. Chemists introduce an ethyl ester to the structure through a strategic condensation step and then convert the product to its hydrochloride salt for stability and solubility. This multi-step route, while established and scalable, still presents hazards; strong acids, bases, and organic solvents require experienced hands and tight controls. In actual industrial practice, safety measures and rigorous purification minimize the risks that trace contaminants could slip into finished batches.
Pethidine’s structure allows easy chemical modification. Small tweaks, like swapping out the ester group or the nitrogen’s substitution, have created analogues with wildly different effects. Some derivatives have greater antitussive or antispasmodic potential, though most never left the lab bench because of side effects or lackluster pain relief. Researchers in recent decades explored converting pethidine to norpethidine, its toxic metabolite, realizing this pathway underpins both safety concerns and clinical dosing limitations. For all its hazards, these metabolic insights shaped how doctors approach safe prescribing of any synthetic opioid.
Walk into hospitals from Berlin to Boston and you’ll hear pethidine referred to by a patchwork of names—meperidine, Demerol, Dolantin among them. Pharmacists and regulators track a tangled list of synonyms to keep supply chains and medication records straight. Each naming convention developed alongside regulatory efforts to stamp out confusion and curb illicit diversion, but still, older clinicians will recognize this drug by whatever name they learned in medical school.
Manufacturers and healthcare professionals can’t afford to ignore pethidine’s potential dangers. Norpethidine, the drug’s primary metabolite, builds up in the bodies of patients with kidney damage, risking seizures. Strict guidelines now warn against repeated or excessive dosing, especially in elderly or pediatric patients. Hospitals put locked cabinets, double-checks, and electronic records in place to keep supplies secure and dosing precise. Training programs for nurses and physicians spell out these rules, as even a single error can mean life-altering toxicity. Laws require pethidine be scheduled as a controlled substance, demanding full accountability from production floor to patient bedside.
Today’s use of pethidine looks very different from its heyday. Doctors still turn to it for relief during childbirth or to control post-operative pain in specific cases, influenced by hospital traditions as much as up-to-date evidence. It holds a shrinking place in pain management, eclipsed by other opioids or entirely different painkillers considered safer for regular use. In veterinary medicine, pethidine still finds a foothold, especially for short surgical procedures. Outside the clinic, regulators flag it as high-risk: reports of abuse and illicit manufacture keep enforcement teams vigilant.
Decades of research have unpacked pethidine’s pharmacology. New studies explore ways to use its chemical backbone for improved painkillers with less dependence or toxicity. Medicinal chemists have logged variant after variant, seeking that elusive opioid with perfect pain relief but minimal side effects. Lately, researchers examine drug-target interactions more closely with computational chemistry and high-throughput screening, betting modern science can wring out hidden value from old molecules. Despite tough competition from newer synthetic opioids, pethidine’s legacy as a research scaffold persists in labs worldwide.
Studies dating back decades flagged norpethidine, pethidine’s main metabolite, as a cause of convulsions and neurotoxicity, especially with prolonged use. Modern health warnings draw from both population data and animal models, which show the metabolite lingers dangerously in patients with impaired kidney function. Research confirms that even therapeutic doses can become hazardous over time, especially in low-weight, elderly, or chronically ill patients. The push to monitor and limit pethidine exposure now draws on a body of peer-reviewed studies, urging clinicians to prioritize alternatives and strictly monitor its use.
Pethidine’s golden era has passed, but bits of its legacy remain. In pain clinics and obstetric wards where rapid, reliable pain relief is needed and long-term dosing isn’t a concern, practitioners may still choose it with caution. The pipeline for novel opioids draws lessons from pethidine’s metabolic and clinical fate, guiding the design of future compounds. Researchers turn to pethidine as a model for testing ideas about opioid signaling and side-effect management. The ongoing opioid crisis forces policymakers to balance therapeutic need with responsible control, prompting ongoing revisions to guidelines and supply monitoring. As science and medicine search for safer pain treatments, pethidine’s story offers both a warning and a road map for progress.
Pethidine, also known as meperidine, stands out as a medicine doctors often turn to for managing moderate to severe pain. Over the years, it has carved out a clear place in surgeries, trauma care, and for pain relief during childbirth. Pethidine is different from over-the-counter painkillers because it acts fast and brings significant relief when pain becomes overwhelming. Unlike medicines such as acetaminophen or ibuprofen, which handle everyday aches, pethidine takes on more intense challenges—broken bones, post-surgical pain, or the struggle of labor pains.
A patient leaving the operating room, wincing in pain, needs something stronger than what’s stocked in the family medicine cabinet. Pethidine delivers that quick hit of relief. Its popularity really soared in the mid-20th century, especially for women in labor who needed help without the grogginess or muscle spasms some other drugs brought along. Unlike morphine, which often triggers vomiting or slows breathing too much, pethidine once seemed like the gold standard for getting pain under control swiftly. In real hospitals and clinics, though, nobody uses it blindly. Trained professionals weigh doses, watch for side effects, and pay close attention to history of addiction or liver issues, because pethidine carries its own risks.
Pethidine brings a sense of relief, but nothing is ever that simple. It can sometimes confuse or agitate patients, especially older ones. Mixing pethidine with other medications, like MAO inhibitors (taken by people with mental health challenges), sometimes leads to dangerous reactions—a risk not everyone realizes until it’s too late. Doctors and nurses watch for twitching, odd mood swings, or shallow breathing, rarely letting their guard down when pethidine enters the plan. People with kidney or liver trouble feel the side effects more, since the medicine and its breakdown products linger, building up to toxic levels. As a result, pethidine now sees less use in many clinics, replaced in part by newer drugs that stick around for less time or carry fewer complications.
Hospitals don’t operate under a single rule book. Every patient shows up with their own story and reactions to painkillers. Health agencies, like the World Health Organization, have stepped back from recommending pethidine as the painkiller of choice. Many hospitals moved toward morphine, fentanyl, or patient-controlled devices that help avoid overdose. Pethidine still plays a part, yet it’s almost always a last resort, kept for people who have trouble with other painkillers or for shorter procedures where its fast-acting nature gives it the edge. For safety, more doctors check kidney and liver function before prescribing it and steer clear of long-term use. Keeping up with training helps providers spot side effects early, respond before bigger problems bubble up, and teach patients about warning signs they might face at home.
Pain relief doesn’t take a one-size-fits-all approach, and real stories from hospitals and clinics highlight why decisions matter. Regulators push for more research, tracking side effects, misuse, and any sign of dependence. Doctors who speak up about confusing side effects from pethidine help shape new rules, share knowledge across their networks, and encourage more conversations about managing pain wisely. Patients who wonder about their choices get the best answers from professionals who not only trust their training, but who also rely on fresh, accurate evidence from around the world.
Pethidine shows up in hospitals and clinics for one clear reason: it blocks pain. People with injuries, those who just had surgery, even women in labor, may hear the doctor talk about pethidine as a way to dial down pain fast. The effect feels obvious to anyone who’s tried it—you feel a heavy relief, a numbness, and for a while, pain no longer hogs your attention. But there’s a lot more packing in with every dose.
Head-spinning dizziness belongs on the top of the list. You sit up in bed after a dose and the room might feel like it tilts. I saw this play out with older adults after hip surgeries. They’d insist on walking before they should, not realizing how wobbly the medicine left them.
Nausea rides close behind. People start with a wave of sickness in their gut, feeling as if they ate something rotten, sometimes needing to keep a bucket handy. Vomiting becomes more than a nuisance after surgery when the stomach wants to stay calm so repairs can heal.
Constipation creeps in quickly, much like other opioid painkillers. A few days in, patients sometimes end up more focused on their stomach than their sore hip or knee. The body gets stubborn with letting go, and this slows things down even weeks after the last shot.
Anxiety or unusual mood swings sometimes show up, surprising people who expect only physical changes. Sleeplessness hits some, while others find themselves more confused than usual—especially people prone to delirium, like older adults or folks with a history of mental health issues.
Pethidine can cause the heart to speed up or the blood pressure to drop. I’ve watched nurses run to catch someone falling or fainting in the recovery room. For people with heart problems, this isn’t a small risk. Seizures can happen too. The risk climbs with higher doses or with longer use, especially if kidneys don’t flush the drug out quickly.
Respiratory depression sits in the warning labels for a reason. Breathing slows down, sometimes dangerously. The risk increases in people with lung conditions, or in babies when pethidine crosses through during labor. Most people won’t feel this at low doses, but in a hospital, the alarms become critical if someone slips into a slow-breathing crisis. I watched a colleague act fast when a patient’s oxygen numbers dropped— giving oxygen and a medicine to reverse the pethidine made all the difference.
Pethidine, like most opioids, attracts the brain in a way that craving can kick in. After just a few doses, some people notice a powerful urge for more. Sometimes withdrawal pops up—an achiness, sweats, or restlessness—once the shots stop. This risk goes up the longer someone stays on the medicine. Nurses and doctors worry about this enough that they monitor and limit doses, and rarely let pethidine linger on a prescription list once the pain eases.
Pain care teams now lean on other medicines to limit pethidine. Ibuprofen, paracetamol, or less risky opioids often compete for first-line treatment. Some hospitals use nerve blocks or local anesthetics instead of heavy hitting painkillers. Better training for staff to spot side effects early cuts down on complications. Regularly asking patients about dizziness, tummy troubles, or confusion keeps the surprises to a minimum.
Nobody wants to face pain left untreated. At the same time, every shot or tablet comes with its own balance of relief and risk, and knowing these side effects makes all the difference in spotting trouble before it takes root. Asking questions and staying honest with doctors creates a safer path—every single time.
Pethidine—sometimes known by its American brand name Demerol—often finds its way into conversations about pain relief, especially in hospitals. It’s not something you pick up at the local pharmacy without serious reason. Pethidine carries a reputation: fast-acting, heavy-duty, and surrounded by a lot of policy. The whole process of giving this drug shows how seriously healthcare workers treat pain control.
Watching a nurse or doctor offer pethidine makes a few things clear. They reach for it when pain screams louder than what other pills or milder injectables can touch. You’ll see them prepare vials or ampoules—tiny glass bottles that keep the medication sterile and ready. Pethidine comes as a clear liquid, and most hospitals keep it tightly controlled in locked boxes because of its addictive potential.
The most common way you’ll see pethidine used is by injection. Sometimes a shot goes into the muscle—what the medical crowd calls intramuscular. Sometimes it's a small needle right under the skin, known as subcutaneous. In emergencies, or for patients who need fast relief, a doctor might inject it straight into a vein—intravenous. Each way changes how quickly the patient feels relief, and also how much nursing care they’ll need right after. The nurse checks blood pressure, breathing, and overall reaction, because things like dizziness or slowed breathing can happen fast.
Oral tablets exist, but in my years around hospitals, I rarely see them handed out. It’s not just about speed. Oral forms take longer to kick in, don’t always settle well on the stomach, and some patients just can’t swallow pills. In pain crises or labor wards, no one wants to wait half an hour for relief. Quick injections fit those moments better.
No one gets pethidine without a talk about side effects. It impairs alertness, breathing, and can trigger nausea. People with certain health problems shouldn’t get it at all. Medical teams weigh risks every time. The opioid crisis in many countries—backed by statistics from the World Health Organization—shows what happens if these drugs spread unchecked. Hospitals use strict checks, double-signatures on drug registers, and regular audits to prevent misuse or errors.
Technology now plays a bigger role. Modern clinics update records in real time, so every dose has a name attached. This accountability prevents mistakes. For patients, smart education makes a difference: clear conversations about risks, honest talk about alternatives, and the promise of another option if side effects appear. Research keeps searching for painkillers that work as well as pethidine—without the addiction risk—but those answers come slow. For now, careful practice and open eyes keep patients safe, making sure those who truly hurt get relief without opening the door to new problems.
Pethidine, known to many as Demerol, shows up in hospitals and clinics mostly to manage severe pain. Often, it gets used during labor when moms ask for relief they can actually feel. It’s quick, and nurses have relied on it for decades, but new research has nudged us to rethink some old habits.
Years ago, doctors wrote up prescriptions for pethidine during childbirth as a routine step. Today, more health practitioners hesitate before giving it out to pregnant or breastfeeding patients. One big reason—pethidine crosses the placenta. So, when a pregnant woman receives it, her baby gets exposed too.
The World Health Organization and several national obstetric associations published warnings about this drug's possible effects. Significant research links pethidine to newborn drowsiness, trouble feeding, and reduced breathing effort, especially when given close to delivery. That’s not a small concern. Newborns breathe and feed on their own within minutes after birth. Anything that blunts those instincts can lead to extra time in the neonatal care unit and distress for new families.
In my own family, we faced a decision about pain relief options during labor. Reading hospital materials and talking to a few nurses shaped my perspective. They talked about alternatives now offered more regularly—epidurals, nitrous oxide, short-acting opioids. Each comes with its own risks and benefits, but pethidine’s reputation for causing side effects in babies kept popping up.
Parents want to protect their babies from risk, but tough labor sometimes leaves folks feeling desperate for help. That’s where honest conversations can change outcomes. I’ve seen relatives encouraged by their doctors to voice every worry and get involved in these medical decisions. Moms often need real answers, not just medical jargon tossed around in a busy delivery ward.
Mothers who choose to breastfeed also face questions about pethidine. The drug shows up in breast milk. The American Academy of Pediatrics warns that babies might get sleepy and have less energy to suckle as a result. Since those first few days make such a difference for long-term breastfeeding, making a cautious choice matters.
Research offers better clarity now. Hospitals try to give the smallest possible dose, or switch to alternatives that clear out of the mother’s system faster. Postpartum rooms echo with talk about baby-friendly methods: skin-to-skin contact, good latching techniques, lactation consultants on hand. Pain relief needs often get balanced with the goal of smooth, successful breastfeeding.
Modern medicine doesn’t stand still. Midwives and OBs know about options that limit risk for both mother and newborn. Short-acting pain relief, such as fentanyl or epidurals, lets mothers stay in control and avoids lingering effects for babies. Hospitals now focus on continuous monitoring so changes in a baby’s breathing or feeding show up early.
Some families ask about non-drug routes—massage, water immersion, focused breathing. Those don’t solve every problem, but they play a bigger role in hospitals aiming for healthier deliveries. Choosing a birth team that values honest discussion helps families decide what feels safest.
Medical safety, especially during childbirth and breastfeeding, means listening to real people and weighing facts. Addiction, breathing problems, and feeding troubles force us to question long-held traditions. Trust grows when families get clear answers and time to think about the tradeoffs. Ultimately, those moments shape the first memories new parents make with their babies.
Pethidine makes its way into emergency rooms and clinics because it eases pain quickly. In the scramble to manage someone’s discomfort, people may not always stop to ask if it works well with everything else that patient is taking. Doctors, nurses, and pharmacists spot problems with mixing medications almost every shift. Just because a drug works doesn’t mean it works well with others.
Pethidine, sometimes branded as meperidine, dampens a person’s response to pain by changing signals in the brain. It sounds simple, but in reality, many things can go sideways due to how the body breaks it down and how it interacts with other medications. Folks often assume that only “new” or “strong” drugs interact, but decades-old painkillers can complicate matters just as much as any modern prescription.
When people use pethidine with some antidepressants, especially drugs called monoamine oxidase inhibitors (MAOIs), they risk a serious reaction. Putting these two together just once has sent patients into medical crisis, sometimes with fatal outcomes. The risk isn’t about a slow build-up — problems can show up after a single dose. For anyone with a detailed medical history or multiple prescriptions, a conversation about those medications could literally be life-saving.
Certain anti-anxiety drugs like benzodiazepines, or even other opioid painkillers, amplify sedation. I’ve watched family members nod off or become unresponsive because nobody checked how the effects stacked up. Pethidine shifts normal reflexes into dangerous territory when used alongside these sedatives. In the worst situations, breathing slows so much that emergency intervention becomes the only hope.
A common scenario involves folks with chronic illness — often older adults — who have medications for their heart, blood pressure, and mood. Antidepressants called SSRIs, antipsychotic medications, and muscle relaxants all shuffle how pethidine is metabolized in the liver. This means more or less of the drug in the bloodstream. As someone who’s helped care for grandparents, I saw how one new pain prescription could upset months of careful balancing, sometimes sending older relatives straight back to the emergency room with confusion or shakiness.
The World Health Organization warned about specific interactions involving pethidine, highlighting its role in cases of serotonin syndrome when paired with antidepressants. A rush of serotonin can cause sweating, fever, or seizures, which is a high price to pay for pain relief. The FDA and many other national agencies have flagged combinations that lead to respiratory depression, which barely gets enough attention outside the medical world.
Checking for interactions should not only be a doctor’s job. Pharmacists have tools to spot red flags and can talk plainly about which combinations pose extra danger. Anyone starting pethidine ought to discuss their medicine cabinet with a healthcare professional who sees the big picture. Keeping an up-to-date list of everything taken — even over-the-counter pills or herbal supplements — stops many close calls.
Pain brings fear, and in those moments, people want quick relief more than anything. Yet a few extra questions and a careful look at all medications can keep that relief from turning into a crisis. No one should feel ashamed to double-check; it’s a sign of taking control, not distrust.
| Names | |
| Preferred IUPAC name | ethyl 1-methyl-4-phenylpiperidine-4-carboxylate |
| Other names |
Meperidine Demerol Dolantine Pethilorfan |
| Pronunciation | /ˈpɛθɪdiːn/ |
| Identifiers | |
| CAS Number | 57-42-1 |
| Beilstein Reference | 1362080 |
| ChEBI | CHEBI:7897 |
| ChEMBL | CHEMBL1407 |
| ChemSpider | 14184 |
| DrugBank | DB00947 |
| ECHA InfoCard | echa.infocard.100.007.944 |
| EC Number | 3.1.3.81 |
| Gmelin Reference | 8207 |
| KEGG | D08344 |
| MeSH | D003032 |
| PubChem CID | 4565 |
| RTECS number | PV6210000 |
| UNII | KB5RKS0697 |
| UN number | UN2733 |
| Properties | |
| Chemical formula | C15H21NO2 |
| Molar mass | 247.338 g/mol |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Density | 0.025 g/cm³ |
| Solubility in water | Soluble |
| log P | 0.86 |
| Acidity (pKa) | 8.63 |
| Basicity (pKb) | 8.73 |
| Magnetic susceptibility (χ) | -77.2×10^−6 cm³/mol |
| Refractive index (nD) | 1.503 |
| Dipole moment | 4.28 Debye |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 321.3 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -91.1 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -3940 kJ mol⁻¹ |
| Pharmacology | |
| ATC code | N02AB02 |
| Hazards | |
| Main hazards | May cause respiratory depression, dependence, drowsiness, nausea, and hypotension. |
| GHS labelling | GHS02, GHS07, GHS08 |
| Pictograms | GHS06, GHS08 |
| Signal word | Danger |
| Hazard statements | H302: Harmful if swallowed. H312: Harmful in contact with skin. H332: Harmful if inhaled. |
| Precautionary statements | Keep out of reach of children. If medical advice is needed, have product container or label at hand. Avoid release to the environment. Dispose of contents/container in accordance with local/regional/national/international regulations. |
| NFPA 704 (fire diamond) | 1-2-1 |
| Flash point | 88°C |
| Autoignition temperature | 323 °C |
| Lethal dose or concentration | LD50 (mouse, IP): 77 mg/kg |
| LD50 (median dose) | LD50 98 mg/kg (intravenous, mouse) |
| NIOSH | NT8050000 |
| PEL (Permissible) | Not established |
| REL (Recommended) | 100 mg |
| IDLH (Immediate danger) | Not established |
| Related compounds | |
| Related compounds |
Morphine Fentanyl Alfentanil Sufentanil Remifentanil Methadone Tramadol Hydrocodone Oxycodone Levorphanol |
