Source: Oakland Tribune, 9/9/97
Contact: tribedit@mail.well.com

Researchers find codeine ineffective for many patients
TOLEDO BLADE

LAS VEGAS One of the most commonly prescribed painrelieving drugs
codeine Is "totally ineffective" in about 20 million Americans,
scientists reported here Monday.

Dr. Alistar Wood, who headed the research, said practicing 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 medicine 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. "They're just not capable of
responding to codeine."

Some physicians may hesitate to give additional pain medication to
patients who already have filled a prescription for codeine, Wood said.
Others respond by increasing the dosage of codeine. Because higher dosages
have no greater effect, patients may continue suffering.

Many patients, he added, are reluctant to ask for more medication when
codeine does not work, thinking they will be considered weaklings or
potential drug abusers.

Wood is a pharmacologist at Vanderbilt University in Nashville, Tennessee.
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, being held here.

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.

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 1 out of every 10 Caucasian people lack
the enzyme, called CYP2D6, needed to metabolize codeine Into morphine.

Importantly, CYP2D6 also metabolizes a wide variety of other drugs in
addition to codeine. These include propranolol (Inderal) and propafenone
(Rymmol), used to treat cardiovascular diseases.