PH7.8 | PH7.8 | Uterine Relaxants and Stimulants — SDL Guide — Summary & Reflection

KEY TAKEAWAYS

Uterine Relaxants and Stimulants — Key Takeaways:

• Oxytocin: IV infusion for induction/augmentation; IM/IV for PPH; phasic contractions; water retention ADR (use normal saline, not dextrose).
• Ergometrine: Tetanic contraction; ONLY post-delivery (NOT for induction — fetal asphyxia); contraindicated in hypertension/pre-eclampsia (vasoconstriction).
• Misoprostol (PGE1): Thermostable, oral/SL/rectal; cervical ripening, induction, PPH; contraindicated for induction in prior caesarean (uterine rupture risk).
• Carboprost (PGF2α): Refractory PPH; CONTRAINDICATED IN ASTHMA (bronchoconstriction).
• PPH sequence: Oxytocin → ergometrine (check BP) → misoprostol → carboprost (no asthma) → surgical.
• Nifedipine: First-line oral tocolytic — blocks Ca²⁺ channels in myometrium.
• Magnesium sulphate: Tocolytic + fetal neuroprotection (cerebral palsy risk reduction) <32 weeks. Antidote: calcium gluconate IV.
• Atosiban: Oxytocin receptor antagonist; fewer maternal ADRs; high cost.
• Indomethacin: NSAID tocolytic; avoid >32 weeks (ductus arteriosus premature closure).
• Goal of tocolysis: 24–48-hour window for fetal corticosteroid (betamethasone) lung maturation.

REFLECT

You are writing a protocol for a rural primary health centre on PPH drug management. The cold chain is unreliable, you may not have IV access, and your only drugs are: oxytocin (ampoule), ergometrine (ampoule), and misoprostol (tablet). Write: (1) the order in which you would administer these drugs in a postpartum woman with a flabby uterus and 700 mL blood loss; (2) what information you need before giving ergometrine; (3) when misoprostol becomes your preferred drug in this setting. Reflect on how the pharmacological properties of these drugs (speed of onset, route flexibility, thermostability, ADR profile) directly shape the protocol design for low-resource obstetric care.