It's important that word get around about this... I've copied the whole article here, because sometimes links from newspapers don't work after a while.
From The Globe & Mail May 10, 2006
http://www.theglobeandmail.com/servlet/story/RTGAM.20060510.wxcodeine10/BNStory/National/homePOSTED AT 5:00 AM EDT ON 10/05/06
Codeine can turn toxic in nursing mothers
Gene transformed drug into morphine, which killed infant
LISA PRIEST
From Wednesday's Globe and Mail
TORONTO — Some mothers prescribed codeine after childbirth carry multiple copies of a gene capable of transforming the common pain reliever into morphine, producing a toxic breast milk that in one case killed a newborn.
The case, to be presented today at a scientific meeting in Toronto, will reveal what is described as the first documented fatality of its kind -- a morphine overdose through the ingestion of breast milk, said Gideon Koren, director of the Hospital for Sick Children's Motherisk Program.
"An estimated 150,000 women a year receive codeine following childbirth," said Dr. Koren, adding that it is commonly prescribed to alleviate the pain of episiotomies and cesarean sections. "Even if the gene is relatively rare, you're talking about a large number of kids at risk."
In this case, the mother of a baby boy was prescribed the tablets, a mixture of codeine and acetaminophen last spring, after an episiotomy, a surgical procedure used to enlarge the vaginal opening before childbirth.
For two weeks, the woman took the drug, not knowing she had multiple copies of the gene, which rapidly metabolizes the drug, Dr. Koren said. As the first-time mother nursed her newborn son, he became very sleepy. He became more difficult to breastfeed and more lethargic by his seventh day.
Concerned, she brought the baby to the doctor. Her physician told her: "Let's wait," according to Dr. Koren, adding that most doctors are not aware of the problem.
By the 12th day, the boy had grey skin and decreased milk intake. He died at home on the 13th day.
About 1 per cent of Caucasians are estimated to have multiple copies of the gene. That compares with 30 per cent of Ethiopians and 10 per cent of Southern Europeans, who are estimated to have the gene in multiple copies.
Strategies to prevent overdoses include not prescribing codeine to nursing mothers, using the drug in lower amounts, and watching babies for signs of morphine overdose and in suspected cases, giving its antidote, naloxone. Testing mothers for the gene is considered a less plausible approach, largely because of cost, Dr. Koren said.
"The fact that codeine is taken by so many women and some have this gene duplication makes it a serious situation," said Dr. Koren, who is also professor of pediatrics, pharmacology, pharmacy and medical genetics at the University of Toronto.
He is to present his findings to the Canadian Therapeutic Congress, a meeting of doctors, scientists and pharmacists who specialize in pharmaceuticals.
Although the American Academy of Pediatrics lists codeine as compatible with breastfeeding, Dr. Koren said there is a "lack of sufficient published data to support this recommendation."
Whatever the case, the drug is popular and is used to alleviate all forms of pain.
Canadian pharmacies dispensed more than 8.7 million prescriptions for the codeine and acetaminophen combination pills from April of 2005 to March of 2006, according to Sue Cavallucci of IMS Health, a private health-information and consulting-services company that serves the pharmaceutical and health-care industries. The drug is made by several drug companies.
In this case, solving the mystery of how the baby died was no easy feat; it required medical detective work worthy of a novel.
When the baby boy was sent to the coroner's office, they initially thought he likely succumbed to sudden infant death syndrome, said Jim Cairns, deputy chief coroner for Ontario.
Toxicology tests were performed on the baby, routine for all sudden and unexplained deaths of children under 2. The tests revealed a morphine level that "wasn't just at the lower end of fatal, it was sky high," Dr. Cairns said. "There was a huge level of morphine that none of us could figure out."
Dr. Cairns contacted Dr. Koren who had a hunch the mother was what is medically referred to as an "ultra rapid metabolizer" of 2D6, a liver enzyme, that transforms codeine into morphine. This enzyme is in the cytochrome P450 family, which processes 25 per cent of all drugs, including those that can cause the most adverse reactions.
This mother exhibited telltale signs of having multiple copies of the 2D6 gene: she suffered constipation and severe drowsiness after taking codeine, Dr. Koren said.
To deal with severe episiotomy pain, she was instructed to take two tablets, each containing a mixture of 30 milligrams of codeine and 500 milligrams of acetaminophen, four times a day or every six hours. On the second day, the dose was cut in half -- she was told to take one tablet every six hours, Dr. Koren said.
Doctors were able to solve the mystery, in part, because she had stored the breast milk she had pumped when her baby wasn't feeding well.
When Dr. Koren tested it, high levels of morphine were revealed. The levels were about ten-fold what the infant would have been given for pain after an operation.
Though the Ontario mother did not want to be identified, she wanted others to know about the problem. She has since given birth to another child, Dr. Koren said.
"She's very eager for other women to know," he said.
"If moms know the dose should be limited, it's important. And anything that looks unusual, mothers should seek medical advice."
