China's drug watchdog has ordered all medicines containing dextropropoxyphene, a painkiller, to be withdrawn from the market because of potentially life-threatening side effects.

A statement on the State Food and Drug Administration (SDA) website Monday said dextropropoxyphene, which had been in use for decades in China, had serious toxic side effects on the heart and could be fatal in high doses.

The administration said the decision was based on both domestic and overseas research results and the advice of domestic experts.

The withdrawal would be gradual to allow time for the safe transfer of patients to appropriate alternative therapies, said the statement.

All companies and institutions should stop producing, marketing or using medicines containing dextropropoxyphene from July 31, it said.

Dextropropoxyphene, available only in the form of prescription-only compound tablets in China, is usually used to treat slight or moderate pain, as well as pain caused by cancer.

The medicines are produced by the Jiangsu Heng Rui Medicine Co. Ltd, and the China National Medicines Guorui Pharmaceutical Co. Ltd. in Anhui Province, said the statement.

Many countries had indicated concern over the safety of medicines containing dextropropoxyphene. The United Kingdom withdrew such medicines in January 2005 and the United States Food and Drug Administration (FDA) withdrew them in November last year.

The European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) recommended such medicines be withdrawn across the European Union in 2009.