A drug producer in northwest China shut down temporarily while authorities investigated claims that its herbal injection caused chills and high fever in some patients, local drug regulators said Monday.

Wang Yongli, spokesman for the Food and Drug Administration of Shaanxi Province, said Xi'an Jiahui Pharmaceutical Co. Ltd. voluntarily closed so that an investigation could be conducted into Shenkang, an injection it produced to treat chronic renal failure.

After receiving injections, 23 patients at the Second Hospital of the Tianjin Medical University in north Tianjin City experienced chills and high fever, said Song Ligang, head of the Center for Adverse Drug Reaction Monitoring of Tianjin. All received prompt treatment and reported feeling better in four to six hours, said Song. The cases were all reported starting on May 11.

The Tianjin Institute for Drug Control said two batches of the drug tested positive in a pyrogen reaction test. Pyrogen reactions include chills, vomiting, high fever (up to 40 Celsius) and falling blood pressure. Severe reactions can be fatal.

Tianjin suspended the use of the drug on May 22. Cities and provinces including Beijing, Liaoning and Jilin also issued notices to hospitals, urging them to watch out for adverse reactions.

Initial investigation showed that the pharmaceutical company was not involved in illegal production, and the investigation would center on possible technical problems, said Wang.

Two problematic batches have already been recalled and now all the injections on the market would be recalled, said Wang.

"The risk is now under control," he said.

Since October, China has recalled herbal injections leading to adverse reactions including ciwujia, shuanghuanglian, yinzhihuang and qingkailing. A man was sentenced to eight years in jail for selling contaminated ciwujia injections that killed three people in southwestern Yunnan Province.

(Xinhua News Agency May 26, 2009)