Regulator forces Pfizer to withdraw painkiller

US regulators have demanded that Pfizer stops selling its painkiller Bextra because of safety concerns, six months after the withdrawal of a similar pill, Vioxx, because it was linked with an increased risk of heart attacks.

US regulators have demanded that Pfizer stops selling its painkiller Bextra because of safety concerns, six months after the withdrawal of a similar pill, Vioxx, because it was linked with an increased risk of heart attacks.

Pfizer, the world's biggest drug maker, has fought to keep its two Cox-2 painkillers on the market, but the Food and Drug Administration brushed aside the company's complaints yesterday - and overruled its own scientific advisory panel - to demand Bextra's withdrawal.

It also demanded that large new safety warnings be added to the label of Celebrex, Pfizer's best-selling Cox-2 pill with sales of $3.3bn (£1.8bn) last year, sending the company's shares lower in New York.

Shares in GlaxoSmithKline, the UK giant which is hoping to launch its own Cox-2 pill at the end of the decade, were down 11p to 1,221p, one of the biggest falls in the FTSE 100. Analysts said the surprise FDA decision made it yet harder for GSK to develop its drug.

Pfizer immediately stopped selling Bextra in the US and in Europe, where it had also been asked to withdraw the drug.

Cox-2s have been linked to an increased risk of strokes and heart attacks since the results of long-term studies of Vioxx, made by Merck of the US, triggered that drug's withdrawal last September. Regulators on both sides of the Atlantic have been reassessing the risks and benefits of Cox-2s since then. Bextra has also been associated with a potentially fatal skin allergy.

Pfizer said it disagrees with the regulatory decisions on Bextra, which had sales in 2004 of $1.3bn, and will explore options with regulators under which it might be allowed to resume sales of the drug.

Pfizer's decision to keep its Cox-2s on the market had attracted strong criticism from some consumer campaigners, and analysts said they feared that class action lawsuits may be triggered by yesterday's FDA rulings.

The agency also asked the makers of dozens of other prescription and non-prescription painkillers, including Motrin, Advil and Aleve, to strengthen warnings about possible heart risks and potentially life-threatening gastrointestinal bleeding. The new warnings do not apply to aspirin.

GSK said it would meet the FDA over the summer to discuss the additional safety trials that are likely to be necessary to gain approval of its new Cox-2, after which its future would be clearer. The company remains committed to developing the drug.