What is the administration protocol for carboprost (15-methyl-PGF2α) in a post-cesarean section patient at risk of postpartum hemorrhage?

Carboprost Administration Protocol for Post-Cesarean Hemorrhage

For postpartum hemorrhage due to uterine atony after cesarean delivery, administer carboprost 250 micrograms (1 mL) deep intramuscularly, with repeat doses every 15-90 minutes as needed, not exceeding 2 milligrams (8 doses) total. 1

Initial Dosing and Route

• Administer 250 micrograms (1 mL) of carboprost tromethamine deep intramuscularly using proper injection technique 1
• The injection must be given deep in the muscle, preferably using a tuberculin syringe for accurate dosing 1
• This represents the standard initial dose for refractory postpartum uterine bleeding 1

Repeat Dosing Protocol

• In clinical trials, 73% of successful cases responded to a single injection, so assess uterine tone before administering additional doses 1
• If bleeding persists, repeat doses can be given at intervals of 15-90 minutes based on clinical response and uterine contractility 1
• The interval between doses should be determined by the attending physician based on ongoing blood loss, uterine tone, and hemodynamic stability 1

Maximum Dosing Limits

• Total cumulative dose must not exceed 2 milligrams (8 doses of 250 micrograms each) for postpartum hemorrhage 1
• This maximum is lower than the 12 milligram limit used for abortion indications, reflecting the different safety profile in the postpartum setting 1

Important Contraindications and Precautions

• Avoid carboprost in women with asthma or reactive airways disease as prostaglandin F2α causes bronchoconstriction 2
• Ergometrine should also be avoided in women with lung disease due to bronchospasm risk, making carboprost a particularly poor choice in this population 2
• Monitor for adverse reactions including vomiting (occurs in 14-51% of patients), nausea, chest congestion, facial flushing, hypertension, and tachycardia 3

Clinical Context and Alternatives

• Carboprost is a second-line uterotonic used when oxytocin fails to control uterine atony 4, 5
• Methylergonovine may be more effective than carboprost as a second-line agent, with one propensity-matched analysis showing 40% lower risk of hemorrhage-related morbidity (RR 1.7 for carboprost vs methylergonovine) 5
• Carboprost combined with oxytocin demonstrates additive or synergistic effects superior to oxytocin alone 4, 6
• A slow intravenous infusion of oxytocin (<2 U/min) should be used as first-line therapy to avoid systemic hypotension 2

Administration Timing Relative to Other Interventions

• Carboprost can be administered after placental delivery when oxytocin fails to achieve adequate uterine tone 1
• Inspect the solution for particulate matter and discoloration prior to administration 1
• Consider tranexamic acid 1 gram intravenously as an adjunct if hemorrhage persists, as it reduces mortality from postpartum hemorrhage 2

Common Pitfalls to Avoid

• Do not use the higher dosing regimen (up to 12 mg) intended for abortion in the postpartum hemorrhage setting—the maximum is 2 mg (8 doses) 1
• Do not administer intravenously—carboprost must be given intramuscularly only 1
• Avoid in patients with cardiovascular disease, as carboprost can cause hypertension and tachycardia 3
• Do not delay surgical intervention (uterine artery ligation, hypogastric artery ligation, or hysterectomy) if pharmacologic management fails 5