Uterotonics update

Uterotonics are the mainstay of management for postpartum haemorrhage and an understanding of their use is essential for the obstetric anaesthetist. First-line uterotonics comprise oxytocin and carbetocin, which act on the oxytocin receptor, and recent research has shown that lower doses of first-line uterotonics can be used to adequate effect. The oxytocin receptor is known to undergo desensitisation with exposure to the agonist over time and with increasing concentrations. Therefore, second-line uterotonics, such as ergometrine, carboprost, sulprostone or misoprostol, need to be considered earlier than they have been in past clinical practice. Choice of second-line uterotonic will vary depending on the comorbidities of the patient. This article will outline each of the available first- and second-line uterotonics, their mechanisms of action, pharmacokinetics, side effects and contraindications. Comparisons between them will also be discussed, as well as differences in superiority and guidance on dosing, based on recent evidence.