Vioxx (rofecoxib) is the first of a new kind of analgesic to be licensed in the UK. It employs a pioneering technology called COX-2 (selective cyclo oygenase 2 inhibitors), which is supposed to offer all the benefits of NSAIDS (non steroidal anti inflammatory drugs) such as aspirin and ibuprofen, but without damaging the stomach.

Although much of the breakthrough research is being carried out at Searle, the pharmaceutical was beaten to the punch by Merck Sharp & Dohme (MSD), which succeeded in getting approval in the UK for Vioxx last December.

In theory, the COX-2 drugs can be used for any kind of pain relief, although MSD is marketing Vioxx as an anti arthritic.

But one party pooper, in the shape of the University of California, has already appeared on the scene. Researchers there doubt that the COX-2 drugs may not protect the gastric lining after all, and may induce ulcers (BMJ, 1999; 319: 1518).

In its own datasheet for the drug, MSD reveals that in a trial of 5,400 people, more than one in 100 complained of heartburn, dyspepsia, nausea and diarrhoea, suggesting that the Californian researchers may be on to something. Other common adverse reactions included abdominal pain, dizziness, fluid retention, hypertension, headache and itching.

Uncommon reactions, reported by more than one in 1,000, included chest pains, acid reflux, constipation, oral ulcers, vomiting, tinnitus, weight gain, cramps, insomnia, vertigo, depression, and dermatitis.

Undaunted, Searle is expected to be next in line for approval of its own COX-2 drug sometime this year. Its research team, which is working with scientists from Pfizer, is very excited about its work, describing it as "a landmark discovery in molecular biology".

It's just a pity that there always seems to be a small voice somewhere saying: "Yes, but. . .".