Match each clinical vignette describing an adverse reaction during the management of postpartum hemorrhage to the underlying mechanism of action of the responsible pharmacologic agent.
- A 29-year-old woman with uterine atony develops severe wheezing, dyspnea, and oxygen desaturation to 88% immediately after intramuscular administration of a uterotonic agent.Synthetic prostaglandin F2-alpha analog that stimulates uterine contractility but also causes significant bronchial smooth muscle constriction.
- A 34-year-old woman with chronic hypertension receives a second-line medication for postpartum hemorrhage and subsequently experiences a severe hypertensive crisis (190/115 mmHg) and a throbbing headache.Ergot alkaloid that induces tetanic uterine contractions and causes potent systemic vasoconstriction via partial alpha-adrenergic and serotonergic agonism.
- A 26-year-old woman receiving a prolonged, high-dose intravenous infusion of a first-line uterotonic agent develops lethargy, confusion, and a generalized tonic-clonic seizure associated with a serum sodium level of 116 mEq/L.Endogenous nonapeptide hormone analog that stimulates uterine contractions but exhibits cross-reactivity with renal V2 receptors, promoting free water retention.
- A 31-year-old woman treated for refractory postpartum hemorrhage complains of severe, sudden-onset diarrhea, nausea, and a transient fever of 38.6°C (101.5°F) shortly after rectal administration of a uterotonic.Synthetic prostaglandin E1 analog that enhances uterine contractility but frequently causes gastrointestinal smooth muscle stimulation and alters the hypothalamic thermoregulatory set point.
Answer
The left clinical vignettes match to their right pharmacologic mechanisms as follows: wheezing matches the PGF2-alpha analog, hypertension matches the ergot alkaloid, hyponatremia matches the nonapeptide hormone analog, and diarrhea/fever matches the PGE1 analog.
Each uterotonic agent has a distinct mechanism of action corresponding directly to its side effect profile. Carboprost (PGF2-alpha) causes bronchospasm. Methylergonovine (ergot alkaloid) causes vasoconstriction and systemic hypertension. Oxytocin (ADH analog) causes water retention and subsequent hyponatremia. Misoprostol (PGE1) causes GI stimulation and fever.
Step-by-Step Solution
Key Concept
Pharmacologic mechanisms and characteristic adverse effects of uterotonic agents used in postpartum hemorrhage
Estimated Time:1m 30s