Relative potency of norepinephrine and mephentermine bolus for the treatment of spinal hypotension during elective caesarean delivery: a randomized, blinded up-down sequential allocation study
Primary result · ED95 and relative ED95 potency ratioResult — go to the resultRelative ED95 potency ratio 222 95% CI 201–242Authors' conclusion
When used as bolus for treatment of spinal hypotension during elective caesarean delivery, norepinephrine is approximately 220 times more potent than mephentermine; therefore, norepinephrine 8 μg is approximately equivalent to mephentermine 1.7 mg.
Study context
- Population
- Healthy parturients with term, uncomplicated, singleton pregnancy undergoing elective caesarean delivery who developed spinal hypotension (>20% fall from baseline SBP)
- Participants
- 100 participants
- Comparison
- Norepinephrine vs mephentermine bolus for spinal hypotension
- Primary endpoint
- ED95 and ED50 of norepinephrine and mephentermine boluses and their relative potency ratio
Methodological detailsblinded, up-down sequential allocation (Narayana rule), dose-finding
- Blinded
- Up-down sequential allocation (Narayana rule)
- Dose-finding
Primary result
ED95 and relative ED95 potency ratio
Relative ED95 potency ratio
222
95% CI 201–242
By group
Norepinephrine
7.2
ED95 · 95% CI 4.9–9.5 · µg
Mephentermine
1.59
ED95 · 95% CI 1.43–1.75 · mg
As reported in the abstract
Further findings
| Outcome | Norepinephrine | Mephentermine | Relative ED50 potency ratio (95% CI) |
|---|---|---|---|
| ED50 and relative ED50 potency ratio | ED50 6.9 (95% CI 6.2–7.7) µg | ED50 1.39 (95% CI 1.33–1.46) mg | 201 (193–210) |
Original publication
Relative potency of norepinephrine and mephentermine bolus for the treatment of spinal hypotension during elective caesarean delivery: a randomized, blinded up-down sequential allocation study. Int J Obstet Anesth. Published 13 July 2025. doi:10.
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