ABSTRACT
MANAGEMENT An algorithm including uterotonics and active management of placenta delivery is shown in Figure 9.1.
Uterotonics Common types of uterotonics include oxytocin, ergot alkaloids like methergine, syntometrine, and prostaglandins (Table 9.1).
Oxytocin (Syntocinon1) Oxytocin binds to specific uterine receptors with immediate action causing increasing strength and frequency of contractions. The mean half-life is 3 minutes with the plateau reached after 30 minutes. It can either be given as intravenous (IV) or intramuscular (IM), though IM injection has time of onset of 3 to 7 minutes and clinical effect is longer, lasting 30 to 60 minutes. It is metabolized by the liver and kidneys with a known 5% antidiuretic effect of vasopressin. If given in large volumes, greater than 40 to 50 cc/min, and high concentration, or when given without dilution, it may result in hyponatremia and syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH) with symptoms of headache, vomiting, drowsiness, and convulsions.
