Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. For postpartum pain management, there is no overall increased risk of persistent opioid use in patients prescribed oxycodone versus codeine upon hospital discharge.

2. For patients with vaginal deliveries, there is an increased risk of persistent opioid use for oxycodone compared to codeine.

3. For patients with C-section deliveries, there is a slightly decreased risk of persistent opioid use for oxycodone compared to codeine.

Evidence Rating Level: 2 (Good)

Study Rundown:

There has been a recent shift away from codeine and towards other opioids for management of pain immediately postpartum. This is due to a 2006 case report that attributed an infant death to morphine toxicity from a breastfeeding mother who was prescribed codeine. This triggered warnings about maternal codeine use from health organizations, though the inciting case report has come under question since. Regardless, there has been a shift to more potent opioids, such as oxycodone, that are associated with more adverse effects, including death and addiction. Therefore, this retrospective cohort study aimed to examine the association between oxycodone and persistent opioid use following childbirth, in comparison with codeine. This study included postpartum patients who filled a codeine or oxycodone prescription upon hospital discharge after delivery. Those who filled an opioid prescription in the 100 days preceding delivery were excluded, to eliminate patients with baseline opioid use. Patients were categorized as having persistent opioid use based on whether they filled opioid prescriptions in the 365 days following the initial prescription on discharge. The indication for subsequent opioid prescription and its relevance to the childbirth was not accounted for. The results of the study found no overall association between persistent opioid use and type of opioid prescribed on discharge, though when examining mode of delivery, there was an increased risk of persistent use for patients delivering vaginally prescribed oxycodone on discharge, with a slightly decreased risk for C-section patients.

In-Depth [retrospective cohort]:

This study included all postpartum patients with records in Ontario, Canada, who delivered between 2012 and 2020, filling either a prescription for codeine or oxycodone in the 7 days following discharge. The index date referred to the date this initial prescription was filled. Those with an opioid prescription, including opioid agonist therapy, in the 100 days prior to the index date were excluded so that the participants would be opioid-naïve. The primary outcome was persistent opioid use, defined as filling at least 1 prescription within 90 days of the index, and at least 1 prescription between 91 and 365 days after the index. In total, there were 70,607 who met the inclusion criteria, 30.2% receiving codeine and 69.8% receiving oxycodone upon discharge. As well, 2.1% met the criteria for persistent opioid use, with 2.41% and 1.92% of the codeine and oxycodone groups respectively. Overall, there was no increased risk for persistent opioid use among patients prescribed oxycodone compared to codeine (relative risk 1.04, 95% CI 0.91-1.20). However, when stratifying by mode of delivery, 2.96% of those delivering vaginally had persistent use, and there was an increased risk for oxycodone compared to codeine (RR 1.63, 95% CI 1.31-2.03). For those delivering by C-section, 1.84% had persistent use, and there was a slightly lower risk for oxycodone compared to codeine (RR 0.85, 95% CI 0.73-1.00). Additionally, other risk factors for persistent use were identified through the study: A prescription with greater than 225 morphine milligram equivalents (MMEs) was associated with double the risk compared to 112.5 MMEs, and a prescription duration for more than 7 days was associated with 1.5 to 2.5 times the risk compared to a 1-3 day duration. In conclusion, oxycodone is not associated with higher risk of persistent opioid use overall, compared to codeine, but there is an increased risk among patients delivering vaginally and a slightly decreased risk for C-section patients.

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