Drugmakers are struggling to justify their pharmaceuticals advertisements, which target US consumers, as the ripples from the Vioxx furore spread.

Health safety concerns have swirled around cox-2 inhibitors since Merck withdrew Vioxx, its popular and now controversial painkiller, in September.

US regulators this week warned Pfizer, the world's biggest drugs company, that its consumer advertising made “misleading” safety and efficacy claims about its cox-2s Celebrex and Bextra, which can potentially cause heart problems.

The Food and Drug Administration's warning of misleading advertising for the two drugs underscores the growing scepticism over pharmaceuticals advertising since the Vioxx controversy. Some critics, such as consumer watchdog groups such as Public Citizen, continue to call for further scrutiny of drug advertising. Although an outright ban is thought unlikely, many analysts say there is a good chance there will be tighter restrictions on the advertising of pharmaceuticals to consumers.

Merck withdrew Vioxx after a study showed normal doses could double heart attack and stroke risk after 18 months. In December, Pfizer said one long-term trial showed Celebrex could have similar risks. That followed a warning that Bextra could have risks for heart surgery patients.

Doctors and pharmaceuticals executives argue that all drugs carry risks in their reactions with each patient's unique physiology, and the wider benefits must be weighed against those risks.

What has changed, however, is that drugs have been marketed on TV and in print since 1997, creating the possibility, some medical experts say, that patients will take drugs unnecessarily.

The role of mass-media advertising of pharmaceuticals is being questioned because marketing helped push Celebrex and Vioxx sales quickly after their launches.

Critics said the drugs were being advertised for all patients, despite the fact that they often did not ease pain better than cheaper, retail medications. Also, they were originally intended for chronic patients because they caused fewer ulcers than older painkillers.

Advertising enables companies to boost use of their new drugs faster. But some observers say this creates a problem as more people use drugs with unanswered safety questions.

“The combination of mass promotion of a medicine with an unknown and suspect safety profile cannot be tolerated in the future,” said Dr Eric Topol, a heart specialist at the Cleveland Clinic and a Vioxx critic, in an article in the Journal of the American Medical Association. “An aggressive position going forward is necessary for not only ensuring the safety of prescription medicines, but also to restore a solid foundation of public trust.”

The FDA has come in for criticism in the wake of Vioxx for being too easy on drugmakers and negligent in its role of policing drug safety.

Its warning to Pfizer signals an effort to show it is getting tougher on the industry. It also shows that the agency could target drug advertising as a significant way to show Congress, industry and the public it is acting to allay drug safety regulation concerns.

In a letter to Pfizer made public on Wednesday, the FDA chastised the US drugmaker for creating public health concerns from its misleading advertisements. Citing a Celebrex print ad, the FDA said Pfizer claimed the drug was “more effective [ie stronger] than ibuprofen and naproxen for the treatment of osteoarthritis or rheumatoid arthritis”. “We are not aware of substantial evidence or substantial clinical experience to support these claims,” the FDA said.

Pfizer had already suspended advertisements for Celebrex in December in compliance with an FDA request after the Celebrex trial disclosure. Bextra was not heavily promoted to consumers.

Pfizer intends to provide regulators with safety data and delay any further decisions on Celebrex and Bextra marketing for an FDA experts panel next month on cox-2 drugs. “We are waiting to discuss the next steps in the appropriate venue with the FDA,” said Susan Bro, Pfizer spokeswoman.

The US is one of few places that allows mass advertising for prescription pharmaceuticals.

Indeed, executives for AstraZeneca and Glaxo-SmithKline on Thursday told a UK parliamentary committee that they would not push for consumer drugs marketing in the UK.

But the future is uncertain as industry and regulators debate the future of drugs advertisements to a more risk-averse public.

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