There isn't a word for diabetes in traditional Chinese medicine, but Chengzhi Xia knows it when he sees it. And he says he's seeing much more of it these days.

Xia and other healers in affluent central Shanghai describe the illness by one of its symptoms: a raging thirst. Patients often seek relief from the side effects of modern drugs - products sometimes outdated in the West.

"Western companies should have more innovative products to give Chinese patients more choices," Xia said in an interview in his cubicle at Lei Yun Shang Pharmacy, where apothecaries sift sharp-smelling medicinal herbs alongside modern pills.

He may soon get his wish. As diabetes rates soar in China, drugmakers including Merck & Co, Sanofi and Eli Lilly & Co are trying to unseat Bayer AG and Novo Nordisk A/S as the biggest providers of diabetes medicines. At stake is a market that may triple to $2.1 billion in annual sales by 2019 from $700 million in 2009, says Yifi Liu, an analyst for Datamonitor in Shanghai.

"You should continue to expect double-digit growth in China's diabetes market for many years to come," Kare Schultz, chief operating officer of Novo Nordisk, said in a telephone interview. The Copenhagen-based drugmaker is the country's top seller of insulin, the hormone that diabetics need to break down the sugar that builds up in their blood stream and convert it into energy.

Beyond insulin, the pill to beat is a 17-year-old Bayer drug called Glucobay, little used in the West but dominant in China. Glucobay sales in China surged 22 percent to 1.8 billion yuan ($283.4 million) last year, according to Bayer. The medicine, now a generic, only garnered a fraction of that, or $9.7 million in revenue, in the US in the first nine months of this year, according to data research firm IMS Health.

The same pace of social change and urban prosperity that has fuelled China's economy over the past decade has fanned the spread of Type 2 diabetes, the most common form of the disease, as people eat fattier foods and lead more sedentary lifestyles.

Type 2 diabetes linked to obesity affected almost one in 10 Chinese adults in 2008, the New England Journal of Medicine said in a study published last year. That would be a higher rate than in the US, where the National Institutes of Health estimates 8.3 percent of the population had diabetes in 2010. Another 148 million Chinese are on their way toward developing the disease.

The new generation of drugs that may relieve sufferers and supplant Glucobay has already begun its march into China.

Merck's Januvia went on sale last year, and Novo's Victoza became available in October. Lilly and Amylin Pharmaceuticals Inc's Byetta won approval in 2009. All three work in different ways to prompt the pancreas to make insulin.