Concerns surrounding the use of codeine in breastfeeding mothers was the subject of two baby gooroo articles published in June and August 2007, following the tragic death of a 12 day old infant.

An investigation into the death of Tariq Jamieson showed that Tariq’s mother has multiple copies of a gene that causes her to metabolize codeine more rapidly than others. Individuals like Ms. Jamieson are referred to as ultra rapid metabolizers. When these individuals take codeine, which is metabolized in the body into morphine, larger amounts of morphine get into their system and (assuming they are breastfeeding mothers) into their breastmilk. When babies ingest high levels of morphine it depresses their central nervous system (CNS). This CNS depression is what caused Tariq Jamieson’s death.

Since then researchers at The University of Western Ontario and The Hospital for Sick Children in Toronto, Canada have been investigating the effect of codeine in breastfed infants to determine whether negative reactions are common enough to warrant a recommendation that all breastfeeding mothers not take codeine.

The results of their study were recently published in the journal Clinical Pharmacology & Therapeutics. According to Dr. Gideon Koren, lead author, nearly half of all infants in North America are delivered by cesarean section or after episiotomy, making pain relief for mothers necessary. Codeine is commonly used for pain relief and is considered by the American Academy of Pediatrics to be ‘compatible with breastfeeding’. However, study results confirm that codeine cannot be considered safe for ‘all’ breastfed infants.

While the gene variant that causes some individuals to rapidly metabolize codeine is rare, the study results suggest that the incidence may be greater than previously thought, ranging from 1 to 30 percent depending upon the ethnic group. Seventy-two mothers participated in the study; only three had multiple copies of the gene. However, the small sample size (72) and the fact that the study participants were self-selected means that more date is needed.

In the meantime, breastfeeding mothers who take codeine need to be cautioned, and their infants carefully watched for signs of central nervous system depression such as sleepiness, slow breathing rate, and poor feeding.

Strategies for preventing overdose include:

• taking the smallest recommended dose
• taking the drug for no more than four days
• monitoring the baby for signs of CNS depression
• contacting your baby’s health care provider right away if you have concerns

Health Canada is studying proposed labeling changes that would clearly identify the possible risks associated with codeine use by breastfeeding mothers. In addition, an attorney representing Ms. Jamieson in a class action suit against the makers of Tylenol 3 is urging the Food and Drug Administration (FDA) to issue a black box warning for all breastfeeding mothers, the strongest warning the FDA gives.

Universal testing for the presence of the gene variant is not cost effective given its rare occurrence. Ultimately the responsibility rests with each parent. Consider the level of pain. Discuss non-codeine containing options with your health care provider. Consider the possible (albeit rare) side effects of codeine containing drugs. Watch your baby carefully for symptoms of overdoes. Contact your baby’s health care provider right away if symptoms appear.

Many mothers will choose to err on the side of caution and avoid codeine containing drugs. But if you are among those who require pain management, you may find it reassuring to know that Canadian pharmacies dispensed more than 5.3 million prescriptions for codeine in 2007.

So before you eliminate codeine as an option, talk with your health care provider. Together you can decide what is best for you and your baby.