Single-centre, randomized, clinical trial of opioid-free analgesia versus routine opioid-based analgesia regimen for the management of acute post-operative pain following caesarean section: study protocol

Olakunle I. Makinde, Samuel E. O. Aigere, Nuvie Oyeyemi, Adedotun D. Adesina


Background: Pain management post-caesarean section is a common source of exposure to opioids in women. To address the rising opioid addiction associated with peri-operative administration, trend in operative analgesia is moving towards opioid-free, multimodal analgesia. We present our protocol for this study so that it may be replicated in other settings and possibly modified for future studies.

Methods: In a Single-centre, non-inferiority, parallel, randomized, controlled, clinical trial with balanced allocation [1:1] into two arms, we compared a peri-operative opioid-free analgesia regimen with a routine post-operative opioid-based analgesia regimen in women undergoing caesarean section under spinal anaesthesia. Primary outcome measures were post-operative pain intensity at 4, 8 and 24 hours (using Numerical Rating Scale) and post-operative pentazocine use. Secondary outcome measures were the incidence of adverse events and Apgar score. Results will be published in a peer-reviewed, open access journal.

Conclusions: This protocol adopted the use of intravenous paracetamol and intravenous NSAID as baseline analgesics. Magnesium sulphate was introduced peri-operatively as part of our opioid-free multimodal analgesia regimen because of its established effect in decreasing post-operative pain and opioid use. We also relied on the preventive analgesic effect of administration of intravenous paracetamol and intravenous magnesium sulphate before surgical incision, continued intraoperatively and post-operatively. In addition, magnesium sulphate is a familiar drug to the obstetrician, readily available and affordable in most settings where comprehensive emergency obstetric care is offered, easy to administer and it has been well tolerated clinically.

Trial registration: This protocol was registered with (Identifier: NCT04539249) on September 3, 2020, prospectively.


Intravenous magnesium sulphate, Intravenous paracetamol, Suppository diclofenac, Caesarean section, Acute post-operative pain, Opioid addiction

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