Herbal medicine may cause kidney failure

Herbal medicines containing toxic aristolochic acids and widely used in India and China, are leaving millions of people exposed to the risk of developing kidney failure and bladder cancer, a new study has warned.

“We have found evidence that many millions of people continue to be exposed to significant health risk due to these herbal medicines, widely used in China and India,” said lead author Professor Graham Lord, from King’s College London.The medicines, used for a wide range of conditions including slimming, asthma and arthritis, are derived from a botanical compound containing aristolochic acids.

These products are now banned in the US and many European countries but the herbs containing this toxic acid can still be bought in China and other countries in Asia and are also available worldwide over the internet.

The scientists reviewed worldwide cases of aristolochic acid nephropathy (AAN) - a type of kidney failure caused by the intake of these acids. They explained the clinical basis for the disease and proposed strategies to help doctors identify it and treat patients more effectively. They suggested that there may be many thousands of cases across Asia that are undiagnosed or misdiagnosed.

“There is also a striking lack of good quality evidence that might help guide the diagnosis and management of AAN,” said Lord, who is also Director of the National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at Guy’s and St Thomas’ NHS Foundation Trust.

The study, published in Annals of Internal Medicine, indicates that regulatory measures that have so far been adopted by national and international agencies may be inadequate in preventing harmful exposure to aristolochic acid.

The compound is linked to many cases of kidney diseases and urothelial cancer, a form of cancer of which bladder cancer is the most known variant.

The authors reviewed the latest data on the epidemiology of AAN. They used several search engines to include all publications that are about or refer to aristolochic acid and Chinese herbal nephropathy and identified 42 different case studies and one trial relating to the management of the disease. The research team consisted of an international collaboration of scientists from Belgium, Czech Republic, Germany and the UK.