Ibrahim 2019.

Study characteristics
Methods	RCT
Participants	Inclusion criteria: Women undergoing elective cesarean delivery under spinal anaesthesia ASA physical status I‐II N = 80 women randomised, 77 analysed Exclusion criteria: Women with infection at the site of injection, coagulopathy or other bleeding diathesis, pre‐existing neurologic deficits, history of hypersensitivity to any of the given drugs, inability to communicate with the investigator and history of chronic opioid use.
Interventions	Intervention: opioid antagonist (Comparison 7) Nalbuphine 0.5 mg Women received IT nalbuphine (0.5 mg) alongside anaesthetic (IT 10 mg of 0.5% hyperbaric bupivacaine with 0.2 mg morphine) in 0.5 mLvolume with total volume 2.5 mL.) N = 40 women randomised to this group but 1 excluded (for PPH and needing surgical intervention) – so 39 in analysis Comparator: placebo IT 10 mg of 0.5% hyperbaric bupivacaine with 0.2 mg morphine) in 0.5 mLvolume with total volume 2.5 mL N = 40 women randomised to this group but 2 excluded (1 for PPH and needing surgical intervention, 1 for sensory block failed) – so 38 in analysis Both groups received bupivacaine and morphine as part of the spinal anaesthesia
Outcomes	Nausea and vomiting
Notes	Setting: Womens Health Hospital, Assiut University, Faculty of Medicine, Egypt Dates: July 2016 ‐ August 2017 Funding source: not reported in English translation of abstract Declaration of interest: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "...computer generated..."
Allocation concealment (selection bias)	Unclear risk	Quote: "... placed in a sealed envelope prior to study initiation...." but no mention of envelopes being opaque or serially numbered
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	As above
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	As above
Incomplete outcome data (attrition bias) All outcomes	Low risk	3/80 (4%) of women were excluded after randomisation
Selective reporting (reporting bias)	High risk	Methods say they will report itching, hypotension, bradycardia but these outcomes not reported. Paracetamol use reported but not listed in outcomes
Other bias	Unclear risk	Baseline data similar but unclear of there may be other biases