Carbetocin

Mechanism (as reported)

Carbetocin is described as an oxytocin analog/long-acting oxytocin analog and is reported in uterotonic reviews to act on the oxytocin receptor (mechanism details beyond receptor interaction were not provided in the supplied sources). [PMID: 36633570, PMID: 39764811, PMID: 35659950]

Key findings (each cites a source)

• A randomized, double-blind, placebo-controlled phase 3 trial investigated intranasal carbetocin as a selective oxytocin replacement therapy in children/adolescents with Prader-Willi syndrome, using outcomes including hyperphagia (HQ-CT) and obsessive-compulsive symptoms (CY-BOCS), with additional measures of anxiousness and distress (PADQ) and CGI-C. [PMID: 36633570] [PMID 36633570]
• In the PWS phase 3 trial, primary endpoints showed numeric improvements in HQ-CT and CY-BOCS that were not statistically significant; the 3.2-mg arm showed nominally significant improvements in HQ-CT, PADQ, and CGI-C versus placebo, and improvements were sustained during long-term follow-up. [PMID: 36633570] [PMID 36633570]
• The most common adverse event reported during the placebo-controlled period in the PWS phase 3 trial was mild to moderate flushing. [PMID: 36633570] [PMID 36633570]
• Reviews described uterine atony as a leading etiology of postpartum hemorrhage and noted that carbetocin is used/considered as an alternative to oxytocin for postpartum hemorrhage prevention. [PMID: 35102109] [PMID 35102109]
• Evidence reviews reported that carbetocin is an oxytocin long-acting analog and that it is among the pharmacologic options considered for postpartum hemorrhage prophylaxis, including being cited as an effective regimen after cesarean delivery in guideline comparisons. [PMID: 38462248] [PMID 38462248]
• In postpartum hemorrhage prevention reviews, carbetocin is described as acting on the oxytocin receptor and having a longer half-time (relative to oxytocin) attributed to its chemical modification of oxytocin. [PMID: 39764811, PMID: 35659950] [PMID 39764811, 35659950]
• A review discussing uterotonic pharmacology stated that oxytocin receptor desensitization can occur with repeated/prolonged exposure and that a uterotonic with a different mechanism should be considered when oxytocin does not restore uterine tone. [PMID: 35659950] [PMID 35659950]
• A review of combined therapy stated that postpartum hemorrhage prevention can involve single or combination uterotonics (with additive/infra-additive/synergistic actions) and that additive or synergistic action of oxytocin combinations with second-line uterotonics may produce greater risk reduction than oxytocin alone. [PMID: 36028160] [PMID 36028160]
• A formulation-focused study used carbetocin as a model peptide to investigate aggregation behavior at high concentration, reporting visible particle formation after 4 hours of shaking stress and describing nucleated aggregation; the study reported that none of the tested excipients prevented aggregation, though aggregation behavior could be altered for some charged excipients. [PMID: 29162423] [PMID 29162423]