The risk of opioid addiction has prompted some Ontario doctors to study how prescribing Oxycodone for pain after childbirth has resulted in some new mothers continuing to use the drugs for weeks and months afterward.
Details were published this week in the current edition of the Canadian Medical Association Journal (CMAJ).
The study was authored by Jonathan S. Zipursky, Karl Everett, Tara Gomes, J. Michael Paterson, Ping Li, Peter C. Austin, Muhammad Mamdani, Joel G. Ray and David N. Juurlink, a group of doctors and researchers connected with Sunnybrook Health Sciences Centre, the Institute of Health Policy, Management, and Evaluation at the University of Toronto, ICES (Institute for Clinical Evaluative Sciences), the Faculty of Pharmacy at U of T, and the Li Ka Shing Knowledge Institute at St. Michael's Hospital.
The study said Oxycodone was increasingly being prescribed for postpartum analgesia (pain relief) in lieu of codeine owing to concerns regarding the neonatal safety of codeine during breastfeeding.
The authors wrote that among postpartum mothers "we found that an initial prescription for Oxycodone was not associated with a higher risk of persistent opioid use relative to codeine overall, although a disproportionately high risk of persistent use after initiation of oxycodone was seen after vaginal delivery."
The study was carried out over an eight-year period in Ontario involving more than 70,000 patients between the ages of 12 and 60 who gave birth and filled a prescription for medications containing either codeine (30 per cent) or Oxycodone (70 per cent).
"We chose codeine as the comparator because it has historically been perceived as a ‘weak opioid’ and, until recently, was the preferred opioid prescribed postpartum,” the study authors write. “Owing in large part to concerns about neonatal safety with breastfeeding, codeine has been supplanted over the past decade by more potent opioids (including oxycodone). In the last decade, in Ontario, Oxycodone has become the most commonly prescribed opioid postpartum."
The study further stated that a key outcome was an increased use of prescription opioids.
"The primary outcome was persistent opioid use, defined as one or more additional opioid prescriptions in the 90 days after the index date (first prescription) and at least one additional prescription between 91 and 365 days after the index date.”
In conclusion, the authors wrote the discovery of persistent opioid use relative to codeine was new, and had not been previously identified as enough to warrant further study.
The authors said health-care professionals should be aware and be ready to modify opioid prescriptions.
"Notably, a high volume of opioids dispensed in the initial postpartum prescription may also be a modifiable risk factor for persistent postpartum opioid use. Awareness of these factors and others related to persistent use may help clinicians tailor opioid prescribing while ensuring adequate analgesia after delivery."
The full text of the CMAJ study can be found online here.
Len Gillis covers health care for Sudbury.com.
