Years into America’s opioid epidemic, as the death toll climbed into the hundreds of thousands, the US Food and Drug Administration (FDA) held a hearing to consider a drug company application to approve a new high-strength painkiller.

The FDA assembles advisory committees of doctors and scientists to weigh the arguments for and against new drugs. In 2012, an opioid 10 times more powerful than regular painkillers, Zohydro ER, was on the agenda. By then, no one was in any doubt about the ravages of the worst drug epidemic in US history. So far, it has claimed at least 350,000 lives. Around 150 people a day are dying in a crisis with roots in the push for the mass prescribing of opioid painkillers that took off two decades ago.

The toll was very much on the minds of the doctors on the committee. They peppered the drug maker’s experts with questions about why another pill was needed when the market was flooded with opioids. An anaesthetist wondered if the relatively small number who would benefit from Zohydro was worth the “huge risk” of unleashing another powerful and highly addictive drug. The doctors asked if the pills would end up ruining more lives than they improved.

If one company was making money from a dangerous drug then others were entitled to too

The senior FDA representative on the committee told the doctors they had no business asking such questions. He admonished the committee, saying that there had to be “a level playing field for industry”. In other words, if one company was making money from a dangerous drug then others were entitled to too, even if it was killing people. Some of the doctors were incredulous. One exclaimed that “the primary thing has to be the public health”, not profits. The committee voted 11-2 against approving Zohydro. A majority of members also said it was not safe even for those it was prescribed to. But the FDA decided it didn’t like the committee’s advice and approved the drug for sale on the grounds that it would benefit a narrow set of patients.

How did it come to this, at a federal agency that built a global reputation in the early 1960s for exacting standards by withholding approval for thalidomide, even as the morning sickness drug was deforming the unborn babies of women across Europe? How did the FDA and other federal agencies fail in their singular purpose of protecting the US public, as the opioid epidemic grew for two decades? The answer carries a warning to the NHS about the risk that creeping privatisation and tangled financial relationships between public health services and big business poses, by opening the door to unwarranted corporate influence over medical policies, practices and standards.

America’s opioid epidemic has complex roots, including an almost evangelical campaign by a group of doctors to overcome what they saw as unreasoned resistance to the use of morphine to treat chronic pain, not just the dying, because of misplaced fears about addiction.

In the end, it was driven by drug makers and their thirst for profits. They used their considerable financial muscle to push the wide prescribing of opioids, until doctors were writing more than 200m prescriptions a year – enough for every adult in the country to take a month’s worth of “heroin in a pill”. They, in effect, wrote pain policies and the training manuals for doctors, because cash-strapped public agencies and medical authorities let them. Within the FDA, some officials pushed for the agency to consider the impact of the epidemic in deciding whether to approve new opioids and whether to limit the prescribing of pills already on the market. But there, too, the industry’s views prevailed, with the drug approval division largely parroting its claim that it was those who became addicted, not the pills and prescribing practices, who were to blame.

The Food and Drug Administration campus

in Silver Spring, Maryland. Photograph: Andrew Harnik/AP

Since a change to the FDA’s funding in the 1990s, it has become so reliant on fees by pharmaceutical manufacturers for the approval of their drugs that it has increasingly treated the industry as a client or a business partner. At the time the fees were introduced, the head of the FDA’s Center for Drug Evaluation and Research, Dr Carl Peck, warned that the new setup shifted some power from the agency to the drug companies. And so it proved.

Former officials say a culture developed inside the agency of avoiding conflict with drug makers. It reiterated the false claims of Purdue Pharma, maker of the powerful OxyContin opioid that kickstarted the epidemic, that the drug was less addictive and more effective than other drugs without requiring proper clinical trials. In the 1990s, the agency faced accusations of covering for the industry over the danger of antidepressants inducing suicide, particularly in teenagers.

The industry’s money also buys access. For more than a decade, big pharma was paying tens of thousands of dollars at a time to have its officials sitting at the same table as FDA officials deciding opioid policies. That was possible in part because the line between regulator and regulated had become increasingly blurred. A former head of the US Centers for Disease Control and Prevention, which first declared the opioid crisis an epidemic, told me that key federal health agencies “had lots of industry money” and that influenced their position on the mass prescribing of opioids.

The Zohydro hearing was a turning point, at least in waking up the FDA to growing public anger at what was widely regarded as its indifference to the epidemic. Dr Margaret Hamburg, who was head of the agency when the drug was approved, acknowledged to me that within the FDA “there had been an under-appreciation of just how serious a problem this was”.

But little has really changed in a healthcare system that is primarily an industry, not a service.

• Chris McGreal is the author of American Overdose