Linda Matthews fell in love with a man who was charming and funny and, like her, loved rugby and true crime. Brad Liefvoort was her soulmate. She could see herself raising a family with him. 

Then came the drugs.

Liefvoort became addicted to oxycodone, prescribed for stomach ulcers. With each refill, he would return to their home in Victoria, Australia, cheerful and energetic. When the drugs ran out, he would go into withdrawal — sweats, exhaustion, anxiety. Desperate for relief, he would call an ambulance to take him to the hospital to get more opioids. 

Somehow, the couple fought through. Liefvoort weaned himself off oxycodone. It was almost miraculous. Life was better. They made it, Matthews thought. And for nearly a year, she was right. 

Then came Liefvoort’s chronic headaches — and a doctor’s prescription for a drug they weren’t familiar with: tapentadol. 

Another opioid. 

Liefvoort trusted his doctor. Matthews worried. 

In the last five years, prescriptions of this lesser-known opioid have surged, propelled by some of the same sorts of misleading assertions about its addictive properties that ignited an opioid crisis that now claims more than 100,000 lives each year worldwide.

Grünenthal, the family-owned German company that developed tapentadol, has marketed the drug as a safer alternative to traditional opioids, downplaying the risk of addiction to doctors and influencing regulation governing how it can be prescribed, an investigation by The Examination and news outlets across six countries has found. 

In a medical journal, Grünenthal employees touted the drug’s supposed “low level of abuse,” a misleading claim repeated in a video posted on the company’s educational website for Latin American doctors. The video also minimizes the drug’s risk of respiratory depression — or slower breathing — even though this is a well-known side effect of opioids acknowledged by health officials across the globe. 

Grünenthal took down the educational website at the end of February following The Examination’s inquiries. 

Seven former Grünenthal employees who worked in the marketing, science and sales divisions also said in interviews for this story that tapentadol causes less dependence than other opioids. 

Grünenthal and other opioid sellers have funded tapentadol-related studies and articles in peer-reviewed journals that suggested tapentadol was less likely to cause dependence or lead to abuse than other opioids. Six independent experts who reviewed this research on behalf of The Examination and its partners reached a unanimous conclusion: There is no convincing evidence to support such claims.

“I have tried to find evidence — solid, impartial evidence — of tapentadol’s less addictive properties, and I have not been able to find this,” said Eveline van Dorp, an anaesthesiologist and epidemiologist with a specific interest in opioid research at Leiden University Medical Center in the Netherlands. 

In Germany, Grünenthal also has promoted tapentadol to doctors as “highly effective” for chronic pain, marketing materials show. The recommendation conflicts with guidance from the World Health Organization, and from regulators in the United States and the United Kingdom. Former sales representatives said they also promoted the drug for chronic pain.

Addiction specialists have called Grünenthal’s promotion misleading and dangerous. “There is a feeling among doctors, nursing staff, but also patients that these are harmless substances,” said Dominikus Bönsch, medical director at the District Hospital Lohr am Main in Bavaria.

“It’s pure nonsense,” he said. “A myth.”

Grünenthal wields wide-ranging influence through funding doctors, medical organizations, patient groups and educational initiatives across Latin America and Europe. In the last decade, Grünenthal has paid more than $9 million to help support at least 900 European patient groups and medical organizations, according to a data analysis by The Examination. One company-funded association lobbied the Mexican Congress to loosen regulations around prescribing tapentadol.

Grünenthal acknowledged in a statement that a “few” company documents previously mischaracterized tapentadol’s addiction risks.

Grünenthal hired an independent auditor to review its opioid-related promotional and educational materials in 2019, the statement said. “We found in some instances that tapentadol was characterized in such documents as having the potential to be less addictive than other strong opioids … this claim was not backed up by sufficient scientific references,” the company said. “We do not promote any opioid medicines as less addictive, causing less dependence, or as less frequently abused than other opioids.”

The risks of abuse and addiction are included in every pack of pills and in product information for doctors, the statement said. And, it said, tapentadol is approved for moderate to severe chronic pain in some countries and the labels vary depending on the regulations.

The World Health Organization, the U.S. Food and Drug Administration and independent doctors have warned that tapentadol, like any other opioid, causes dependence and has potential for addiction, misuse and abuse.

Escalating harms

Grünenthal, headquartered in Aachen, Germany, gained notoriety in the late 1950s after the company introduced thalidomide, branded as Contergan. Aimed at helping pregnant women manage morning sickness, the drug instead caused thousands of miscarriages, stillbirths, infant deaths and children born with stunted or missing limbs. 

In 1977, Grünenthal pivoted to making opioids and introduced tramadol, a blockbuster drug for pain. Tramadol, now off patent and also produced by generic manufacturers, has led to a global wave of abuse and addiction in the past decade. In regions like West Africa, illicit manufacturers have flooded the market, and tramadol is often called “poor man’s cocaine.” Experts estimate that thousands of people die every year from tramadol-related overdoses.

As patents on tramadol expired, Grünenthal developed a sibling drug, tapentadol, which was approved in 2008 in the U.S., and 2010 in Europe and Australia. Branded as Palexia or Nucynta depending on the country, the drug soon became Grünenthal’s top-selling product. Sales accounted for nearly 20% of Grünenthal’s total revenue from 2019 to 2022, before dropping to 9% in 2024 after it came off patent in some regions. 

Grünenthal sells tapentadol in Europe and Latin America, and collects royalties from companies it licenses to sell the drug elsewhere.

Tapentadol sales and prescriptions have risen around the globe in recent years in at least 10 countries, including Germany, the U.S. and Mexico, according to data collected by The Examination. 

In Spain, tapentadol prescriptions have now surpassed oxycodone. In Australia, tapentadol has become the most prescribed opioid. CSL Seqirus, which holds a license to sell the drug, boasted last year that tapentadol has been the “only opioid with consistent growth.” In Colombia, sales of tapentadol rose by nearly 50% between 2022 and 2023.

As prescriptions have increased, so have reports of addiction and death.

In Victoria, Australia, coroners recently reported dozens of previously unseen tapentadol-related overdose deaths. In India, psychiatrists are warning of a troubling increase in teenage boys buying tapentadol from dealers and injecting it. And in the U.S., doctors from addiction clinics told The Examination they are seeing an uptick in patients dependent on the drug.

Many countries are not tracking tapentadol-related addictions or overdoses, leaving the scope of the problem largely unknown and unchecked, the investigation found.

Rob Poole, a psychiatrist who ran a clinic in Wales to help patients come off opioids, said many pain doctors are enthusiastic about tapentadol, prescribing it as a “wonder drug” and “miracle cure.”

Poole described Grünenthal’s promotion of tapentadol as “a classic drug company disinformation campaign.”

Simon Gill, a pharmacist and independent prescriber in Wales, said he’s seeing the fallout from the growth  of prescriptions. He said people who aren’t addicts and are taking the medication as prescribed are becoming dependent and suffering life-changing side effects. 

Many patients are finding it extremely difficult and distressing to come off the drug, he said. 

Lucas Trautman, medical director at Oxford Treatment Center in Etta, Mississippi, said that in the past three years his center has gone from seeing hardly any patients dependent on tapentadol to regularly treating such clients. 

“This is a medication that should be treated as an opioid, and doctors do not always communicate that to the patient,” he said. 

In Australia, tapentadol overdose deaths are not counted separately on a national level, but a report by the Coroners Court of Victoria noted an increase from zero to 118 overdose deaths over a seven-year stretch ending in 2023. 

“The rise in tapentadol-involved overdose deaths is reminiscent of what happened when other analgesic products (such as extended release oxycodone …) were introduced,” the report states. “Like these products, tapentadol was initially promoted with claims that it is safer, has lower abuse potential and less risk of adverse events than similar existing drugs. … Regardless of its relative ‘safety’ tapentadol still presents risks to those who use it.”

CSL Seqirus said in a statement that the report’s findings show that, as with all opioids, there is an “ongoing need to ensure all health care professionals are aware that tapentadol has potential for harm.” 

A company spokesperson pointed to a study that found tapentadol was not the sole drug involved in any overdose death in Australia prior to 2021.

‘Completely destroyed’

The spark was back in Liefvoort and Matthews’ life. They hosted game nights, took weekend trips. Liefvoort felt excited to be alive.  

But the tapentadol prescription for his severe headaches triggered a relapse. His addiction raged, and he began alternating tapentadol and oxycodone, shopping for doctors who would prescribe them. Unable to keep a job, he became increasingly secluded. 

After Matthews gave birth to triplets, Liefvoort was on such high doses of medication that he was constantly drowsy and could hardly help with the children. He stole pain medication she had been prescribed after her cesarean section. 

An otherwise peaceful person, during withdrawal, Liefvoort became irritable and aggressive. During one fight, he threw a showerhead, smashing a ceramic soap holder to pieces. He would vomit and shake so severely Matthews didn’t feel it was safe for him to hold the babies.

“There was no trace of him left,” Matthews said. “The drugs had completely destroyed him.”

When Liefvoort skipped the triplets’ first Christmas, Matthews, seeing no hope, asked him to move out. He would be welcome to visit the children. 

Claims about tapentadol being less likely to be abused or cause addiction also are contradicted by experiences unfolding in India, where generic pharmaceutical companies rather than Grünenthal sell the drug. The number of teenage boys becoming addicted to tapentadol has risen sharply since 2017, according to psychiatrists at a major addiction center who asked to remain anonymous after receiving threats to their safety for talking publicly about tapentadol addiction. Other centers have reported a similar rise.

The patients presenting with tapentadol addiction are usually from impoverished areas and buy the tablets to crush, mix with water and inject. The psychiatrists said the hospital now treats around 30 young men a month, the same number they treat for alcoholism. The men usually come for treatment only when the cost of buying tapentadol becomes too high. Coming off the drug, they experience nausea, vomiting and loss of appetite, and suffer severe irritability and cravings.

One 21-year-old patient who became addicted in high school said he experienced insomnia, feeling ill and weak and tired all the time when he withdrew from the drug. “When I’d wake up in the morning, I wouldn’t have the energy to even brush my teeth, wash my face, do anything at all,” he said in an interview with one of the psychiatrists. “If someone spoke to me, I would just respond with ‘hmm’ or a nod. I would not even respond to them. I would always be sad.”

India’s burgeoning addiction problem should serve as a warning to other countries, the psychiatrists said.

Industry-funded studies

So where did the notion that tapentadol is a safer opioid originate? A 2017 lawsuit by the state of Oklahoma against opioid manufacturers offers insight. 

Documents from the lawsuit suggest that in 2009, when Johnson & Johnson held a license to sell the drug, the company’s “tapentadol team” ghostwrote at least a dozen academic manuscripts. Many were written by the company and shopped around to various academics to sign off on them, according to Bristol University researchers who reviewed the files. Some papers were fully drafted before the “primary authors” were even chosen, the researchers found. 

One of the theories for the drug’s supposed less-addictive properties: a so-called dual mechanism, relieving pain without relying solely on the body’s opioid receptors.

A 2012 email exchange between coauthors of a paper about tapentadol’s abuse potential, documented in the lawsuit, shows that even at the time, researchers were casting doubt on the claim. Writing to an individual from a medical communications agency called MedErgy, Theodore Cicero, psychiatry professor at Washington University in St Louis, admitted he had no evidence that the drug’s dual mechanism made it less likely to cause dependence than other opioids. “I don’t know of any evidence to support that, but I can live with the people at J&J … believing this to be true,” he said, and asked that his concerns be forwarded to all coauthors.

Richard Dart, executive director of Rocky Mountain Poison and Drug Safety and lead author on the paper, replied, “I don’t completely get it either,” in an email sent to his coauthors and three Johnson & Johnson employees.

Still, the claim made it into the final publication.

Dart told The Examination in an email that the paper was not influenced by Johson & Johnson or MedErgy. Cicero did not respond to a request for comment.

Johnson & Johnson was ordered to pay a $465 million fine in 2019 for intentionally overstating the benefits and understating the risks of prescription opioids. This judgment was later overturned by the Oklahoma Supreme Court, which ruled the district court judge had relied on a law that did not apply. In 2022, the company agreed to pay $5 billion in a nationwide settlement, without admitting wrongdoing. Johnson & Johnson, which no longer sells prescription opioids in the U.S., did not respond to requests for comment.

Studies and articles in medical journals written by employees of Grünenthal, its licensees or researchers that received funding from the company, also have suggested that tapentadol causes less dependence or addiction and is less likely to be abused than other opioids. 

In a 2014 article published in the peer-reviewed journal CNS Drugs, Grünenthal employees claimed that “the reduced dependence seen with tapentadol” might be due to its dual mechanism. “Furthermore, a low level of abuse and diversion is beginning to emerge” from initial data, the authors said. 

In 2015, a study sponsored by Janssen, a division of Johnson & Johnson, said “tapentadol abuse was seen infrequently in this study and, on a prescription basis, was less likely to be abused than most of the examined Schedule II analgesics.” 

Medical experts who reviewed these and other studies for The Examination identified a variety of shortcomings. For example, one was not designed to measure dependence; another was carried out when tapentadol had been on the market for only a short time, making it impossible to compare abuse potential with drugs that had been on the market for decades.

“The studies do NOT permit the conclusion that tapentadol leads to less dependence with any certainty,” Kyla Thomas, professor of public health medicine at Bristol Medical School, wrote in an email to The Examination. 

U.S. regulators have agreed. When reviewing the application for tapentadol’s approval, the FDA concluded that “tapentadol displays high abuse potential.” 

The World Health Organization in 2014 also raised concerns about tapentadol, noting its short-lasting pleasant effects could encourage more frequent use.

French and Canadian health authorities have issued recommendations against reimbursing prescriptions for slow-release tapentadol, citing its high cost, lack of evidence the drug is beneficial for chronic pain, and concerns about abuse.

Promoted as less addictive

Despite the flawed studies and growing evidence documenting the dangers of tapentadol, Grünenthal employees continued to make misleading claims about the drug — in conversations with doctors and, after they left the company, in interviews for this story. 

At least seven former Grünenthal employees in Germany and the U.K. said they promoted tapentadol as less likely to cause dependence or as suitable for chronic pain. 

Brigitte Gäng worked as a sales representative for Grünenthal Germany between 2002 and 2020, according to her LinkedIn profile. Gäng told The Examination via the platform that “dependence/addiction was never an issue” with tapentadol. 

Another German pharmaceutical representative who left Grünenthal in 2023 after six years and did not want to be named out of fear for her career, said she marketed the drug to doctors as less likely to cause dependence. Grünenthal taught sales representatives to promote the drug this way using study data, written materials and seminars, she said.

When The Examination told her Grünenthal said it doesn’t promote the drug in this way, she expressed surprise. 

Jan-Uwe Claas, a former senior vice president for marketing in Europe, who worked for Grünenthal for two decades until 2022, was responsible for tapentadol’s marketing internationally from the day it was launched. Claas downplayed the possibility of addiction in an interview with The Examination, saying tapentadol, when given in a tablet that slowly releases the drug, does not cause any euphoric feelings like classic opioids do. The argument resembles one made about OxyContin that has been widely debunked. 

He said the drug was suitable for conditions like severe chronic back pain and osteoarthritis, and that the company’s vision was for tapentadol to replace oxycodone globally, adding that the company was “partially successful” in doing so. 

“I can’t see really this kind of risk for addiction and crushing of tablets,” he said. “It has no street value.”

In the last five years in the U.S., customs officials have seized more than 20,000 illicit shipments of tapentadol coming into the country, often from India, destined for addresses across the states, according to U.S. Customs and Border Protection records. Officials estimated the value of pills confiscated in one six-month period at $1.3 million. 

In October, London police seized 730 kilograms (1,609 pounds) of painkillers imported from India, including tapentadol, worth a total of $1.3 million. 

A BBC investigation in February found Indian generic companies had illegally exported millions of tablets containing tapentadol to Ghana and other West African countries, fueling an addiction crisis in the region.

‘Income for everyone’

A video on Grünenthal’s educational site for Latin American health care professionals featured Silvia Allende Pérez, head of a public pain clinic in Mexico and former Grünenthal employee. In it, she promoted tapentadol and its “advantages over other opioids,” and included a Grünenthal-branded slide claiming tapentadol has a “minimum potential of abuse.” 

The slide also said “respiratory depression, not reported” despite this condition being a well-known side effect of opioids and listed as such by Mexican health officials. 

Grünenthal said in a statement that it agreed that its video did not reflect current evidence and that following The Examination’s inquiry it has removed the video and taken the website offline while it reviews its content. Allende Pérez did not respond to requests for comment.

Grünenthal also has helped fund the Mexican Association for the Study and Treatment of Pain, according to Angel Juárez, president of the organization until last year. The association, established in the 1980s, hosts conferences and diploma courses for health care professionals.

Another of the association’s past presidents, María del Rocío Guillén Núñez, has lobbied lawmakers to make it easier to prescribe tapentadol. 

During a forum in the Mexican Senate in 2021 Guillén Núñez spoke out in favor of loosening regulations around tapentadol prescriptions, highlighting its “safety profile.”

A 2017 article on pain states that Guillén Núñez has sat on Grünenthal’s board and received speakers’ fees from the company.

Guillén Núñez said in an interview with The Examination that she believes tapentadol should be treated more like an antidepressant. 

Colombia approved tapentadol for inclusion among state-funded medicines in 2021. Two doctors involved in one of the reviews that led to the decision were past and current presidents of a pain association that has received funding from Grünenthal. The team considered Grünenthal-funded articles in their review. 

In Peru, Enrique Orrillo, a neurologist and president of the Peruvian Association for the Study of Pain, launched in 1995, told a room of doctors at a Grünenthal-sponsored conference in Lima last year that tapentadol is “less addictive than traditional opioids” and heralded the drug as a means to generate profits for doctors.

Satisfied patients can attract more patients, Orrillo said. “This, in the end, generates income for everyone.” 

Orrillo works as a consultant for Grünenthal and runs a company-sponsored class on chronic pain at the prestigious National University of San Marcos in Lima.  

In an interview, Orrillo defended tapentadol’s benefits and pointed to international studies.

“I did not invent those,” he said.

Grünenthal said in response that it operates with the “highest ethical standards” when partnering with health care professionals and organizations.

The claim that tapentadol is a safer opioid has been repeated by doctors across the globe. 

In Wales, the Abertawe Bro Morgannwg University Health Board raised warnings in an internal report about Grünenthal’s marketing of tapentadol in 2019 after discovering the area had more prescriptions than anywhere else in the country.

“Tapentadol is extremely similar to tramadol which was also launched (by the same pharmaceutical company) with similar claims of safety, tolerability and lack of ‘addiction’ potential, all of which have subsequently been proven false,” the authors wrote.

Caroline Hildenbrand-Nixdorf, a family doctor in northern Bavaria, said Grünenthal sales representatives encouraged tapentadol’s use for chronic pain, telling her it was “not an opioid” but a “hybrid between an opioid and normal pain medication” that leads to “no or little dependence.” Their claims convinced her to prescribe the drug. One of her patients is now struggling to come off it.

In Australia, five months after Liefvoort and Matthews separated, Liefvoort’s mother called Matthews. Liefvoort wasn’t answering calls or texts. Matthews sent her father to check on him. When nobody answered the door, he called the police.

They found Liefvoort dead, lying on his bed, clutching pills in his hand. A coroner’s report found he had overdosed on tapentadol and oxycodone, both drugs found in life-threatening amounts.

In the six months before Liefvoort’s death, he had been prescribed opioids by more than 10 different doctors.

“Brad made some really, really bad decisions,” Matthews said. “But he shouldn't ever have been able to get the amount of stuff that he was getting.”

This story is part of the World of Pain project, an investigative reporting collaboration involving The Examination, Paper Trail Media, Latin American Center for Investigative Journalism (CLIP), PlatôBR, Salud Con Lupa, El Espectador and Der Spiegel.

Contributing reporting by Susanne Amann, Andrés Bermúdez Liévano, Maria Christoph, Pamela Huerta, Dajana Kollig, Bruna Lima, Jason Martínez, Iván Paredes Tamayo, Brayan Ramos, Ruben Schaar, Elisa Simantke, Sergio Silva Numa, Iván Ruiz, and Fabiola Torres.

Story editing by Raquel Rutledge. Data editing by Mago Torres and analysis by Fer Aguirre. Visual editing by Taylor Turner and Daniel Nass. Illustrations by Alejandra Saavedra Lopez. European payments analysis was done with support from Euros for Docs.