Pain killer might make cancer list

SACRAMENTO — A fight is coming to California over whether to list one of the world’s most common over-thecounter drugs as a carcinogen, echoing recent high-profile battles over such substances as alcohol and coffee.

The drug is acetaminophen, known outside the United States as paracetamol and used to treat pain and fevers. It is the basis for more than 600 prescription and over-thecounter medications for adults and children, found in brands including Tylenol, Excedrin, Sudafed, Robitussin and Theraflu.

Acetaminophen has been available in the U.S. without a prescription since 1955. Concern about its potential link to cancer comes from its relationship to another drug: phenacetin. That drug, once a treatment for headaches and other ailments, was banned by the U.S. Food and Drug Administration in 1983 because it caused cancer.

California regulators have reviewed 133 studies about acetaminophen, all of which were published in peer-reviewed journals. Some studies reported an increased risk of some types of cancers, while others did not. Overall, the review noted acetaminophen has been difficult to examine because it is hard to isolate from other variables that could contribute to cancer, such as smoking.

Proposition 65 says California must warn people of any chemical known to cause cancer or reproductive toxicity. The state’s list has grown to about 900 chemicals, including toxic pesticides and flame retardants, and is more extensive than any other such list in the U.S. Some say California regulators have been overzealous.

Evidence for acetaminophen’s link to cancer has been weak enough that the International Agency for Research on Cancer declined to list it as a possible carcinogen after reviews in 1990 and 1999.

A panel of scientists appointed by the governor can add chemicals to this list. In 2011, the panel voted to make acetaminophen a “high priority” for consideration because it believed there was relevant evidence to consider, according to a state spokesman.