Rocky Mountain News, Sept. 9, 1997

-Researcher emphasizes necessity to inform doctors of problem-
by Michael Woods-Toledo Blade

One of the most commonly prescribed pain-relieving drugs-codeine-is "totally ineffective" in about 20 million Americans, scientists reported here Monday.

Dr. Alistar Wood, who headed the research, said physicians generally are not aware of the situation.

As a result, patients treated with codeine sometimes suffer unnecessary pain after dental procedures, injuries, minor surgery and other medical problems. Codeine often is prescribed as a combination with acetaminophen, or Tylenol.

"This is really an issue of sensitizing physicians to the fact that these people may not be wimps," Wood said in an interview. "They're just not capable of responding to codeine."

Codeine relieves pain mainly because an enzyme in the liver chemically breaks down, or metabolizes, codeine into morphine. The morphine is responsible for most of the pain relief.

Wood's research found that about one of every 10 Anglos lack the enzyme, called CYP2D6, needed to metabolize codeine into morphine. Some physicians may hesitate to give additional pain medication to patients who already have filled a prescription for codeine, said. Other by increasing the dosage of codeine. Since higher dosages have no greater effect, patients may continue suffering.

Many patients, he added, are reluctant to ask for more medication when codeine doesn't work, thinking they will be considered weaklings or potential drug abusers. Wood is a pharmacologist at Vanderbilt University in Nashville, Tenn. He heads a research group that studies individual variations in human response to drugs. He reported the codeine findings at the 214th national meeting of the American Chemical Society.

Many drugs produce their effects in the body directly, as a result of the "parent" chemical compound in the original medicine. Codeine and certain other drugs, however, work indirectly through "daughter" compounds formed from the original medication.