Buprenorphine And Methadone In Pregnancy: Peripartum Analgesia and Anaesthesia
Dr Cameron Main, Flinders Medical Centre, Adelaide, SA
Dr Brenda Cassidy, Women's and Children's Hospital, Adelaide, SA
Purpose of Study
High dose buprenorphine, used as an alternative to methadone in the management of heroin addiction, complicates the provision of perioperative analgesia (1). Diffculties in the provision of peripartum analgesia and anaesthesia in opioid tolerant women gave previously been descibed (2), however information specific to the implications of buprenorphine use in pregnancy is limited.
Method
Following Institutional Ethics Committee approval a retrospective case note and anesthetic record review was performed of patients enrolled in a trial investigating the neonatal effects of buprenorphine and methadone in pregnancy.
Result
There were 25 births to women in the buprenorphine group, 28 in the methadone group, and 23 to controls. Maintenance buprenorphine and methadone were continued in the peripartum period with no documented emergency calls, no opioid .withdrawl symptoms, and no common opioid side effects noted.
In labour, epidural analgesia was established and maintained by intermittent bolus of local anesthetic with or without fentanyl and was effective in all women. Patient Controlled Analgesia (PCA) using fentanyl was effective for two buprenorphine maintained women.
5 LSCS were performed in the buprenorphine group, 3 with spinal anaesthesia, one by combined spinal-epidural (CSE), and one by epidural top-up. Convesion of one spinal to general anesthesia occured, and this patient required an increased dose of fentanyl by PCA to achieve post-operative analgesia. One women who received 150 mcg intrathecal morphine had severe post-operative pain that was resistent to100mg of intravenous morphine. Analgesia was achieved using intravenous clonidine 30mg and a ketamine infusion at 4mg/hr. Post-operative epiduaral infusion of 0.2% ropivivaine with 4mcg/ml fentanyl provided excellent analgesia in one patient.
5 LSCS were performed in the methadone group, 4 with spinal anesthesia and one by epidural top-up. Two women required an increase in the prescibed post-operative opioid dose. 1 LSCS was performed in the control group by top-up of an existing epidural.
Conclusion
Buprenorphine and methadone may be continued in the peripartum period however difficulties with the provision of peripatrum anlgesia and anaethesia should be anticipated. In opioid maintained women epidural analgesia for labour is safe and effective. In women with contraindications to epidural analgesia intravenous fentanyl may be effective. During LSCS spinal anaesthesia may be ineffective, and supplementation should be anticipated. Consider the use of CSE to allow intraoperative addition to regional anaesthesia.
Multimodal post-operative analgesia should be planned. While neuraxial or systemic opioid analgesia may be adequate, failure of analgesia should be anticipated. Opioid doses may need to be titrated. Adjuvants such as ketamine and clonidine can be useful. Post-operative epidural local anaesthic infusion is effective, and if post-operative analgesia is problematic consider siting an epidural catheter. Observation for sedation and respiratory depression is advised when neuraxial and systemic opioids are required.
References
1. Roberts DM, Meyer-Witting M High Dose Buprenorphine: Perioperative Precautions and Management Strategies. Anaesth Intensive Care 2005; 33: 17-25
2. Cassidy B, Cyna AM. Challenges that opioid- dependent women present to the obstetric anaesthetist. Anaesth Intensive Care 2004: 32: 494-501
