Jonasson and colleagues have published widely on Dextropropoxyphene (Darvon and Darvocet) deaths in Sweden. Following the publication of these reports and the involvement of politicians, the Swedish Medical Products Agency (MPA) held a seminar in spring 1999 focusing on the pharmacological and toxicological aspects of dextropropoxyphene (DXP). The following year, the MPA advised manufacturers to improve summaries of product characteristics, labeling and patient information leaflets to include more specific warnings about overdose and concomitant use of alcohol. Doctors were encouraged to prescribe smaller amounts, and not to prescribe to vulnerable patients.
Stricter prescribing regulations were introduced in June 2001, involving the use of a special prescription form and stringent monitoring of treatment efficacy. The effectiveness of these measures was assessed by Jonasson and Jonasson, who reported that sales of dextropropoxyphene products decreased by 66 percent between 1999 and early 2003, and the number of fatal dextropropoxyphene poisonings decreased by 62 percent between 2000 and early 2003.
Why didn't the FDA follow up on these studies? "Since 1999 we have informed the FDA about our research, and they know about our eight scientific articles about DXP and our two doctorial dissertations (2000 and 2001)," says Jonasson, "but Sweden is a small country and our legal system is different."
Jonasson is referring to the difference between the laws governing medical examiners and coroners. In Sweden, there is one legal system on the federal level, which dictates that every autopsy must be screened for legal drugs—including Darvon. In the US medical examiners and coroners are under county law—performing blood tests with an autopsy is rarely done because it is cost-prohibitive. "This is why Sweden has data that show Darvon is the worst drug ever, which is documented at the International Narcotic Control in Vienna," says Jonasson.
"We studied 1,600 people who died with Darvon in their blood. To put it into a nutshell, Darvon affects your heart muscles and you forget to breathe, so people die," Jonasson explains. "Our research was behind the decision in Sweden, the UK, and The European Union (EU) to stop the drug but it took a lot longer in the US."
By 1977, propoxyphene (Darvon, Darvon-N, Dolene) was the second most common drug involved in deaths from prescribed drugs in the US, and was estimated to cause between 1,000 and 2,000 deaths per year. On November 19, 2010, the FDA asked manufacturers of products containing dextropropoxyphene to withdraw them from sale. An estimated 10 million patients have used these products.
Why did the FDA wait until 2010 to have the drug withdrawn? "We believe the FDA is influenced very much by the drug companies, and we know that Eli Lilly, the Darvon manufacturer, has known about Darvon side effects for many years," says Jonasson.
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(A $4.85 billion settlement fund paid claims from Merck, the maker of Vioxx, to the families of users of its painkiller who died of heart attacks or strokes.)