A patient undergoes uterine balloon tamponade for atonic PPH following failed bimanual compression and oxytocin infusion. The balloon is inflated with 500 mL saline but bleeding continues. Which pharmacological agent should now be added, and what is its mechanism?

• A Tranexamic acid — inhibits fibrinolysis by blocking plasminogen activation on fibrin
• B Recombinant Factor VIIa — activates extrinsic coagulation pathway on activated platelet surfaces
• C Dinoprostone — PGE2 analog relaxing cervix while causing uterine contraction
• D Carboprost (15-methyl PGF2α) — binds myometrial PGF2 receptors causing tetanic uterine contraction ✓

Explanation

Carboprost (15-methyl PGF2α, Hemabate) is a potent oxytocic acting on prostaglandin FP receptors on myometrial smooth muscle, producing sustained tetanic contraction with cervical involvement. It is given intramuscularly (250 μg every 15–90 min, max 8 doses) when oxytocin fails. Tranexamic acid (WOMAN trial) is used in traumatic/atonic PPH and reduces mortality from hemorrhage, but is an adjunct, not the primary uterotonic after oxytocin failure. Dinoprostone is primarily a cervical ripening agent. rFVIIa is a last resort.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.