Oxytocics are agents which increase the force of uterine contraction.
|Class||Endogenous (typically synthetic version used) posterior pituitary hormone||Ergot alkaloid||Prostaglandin|
|Uses||Augmentation of labour, increase uterine tone (PPH)||PPH||PPH|
|Presentation||Clear liquid at 5-10 U.ml-1|
|Route of Administration||IV||IV, IM||Intramyometrial injection, IM|
|Dosing||1.5-12mU.min-1||250μg IM (IV in emergency via slow push)|
|Metabolism||Oxytocinases in liver and kidney|
|Mechanism of Action||Oxytocin GPCR in the uterus, increase Ca2+ influx. Structurally similar to ADH.||Acts on α and 5HT2 receptors on uterine and vascular smooth muscle|
|Resp||Bronchospasm (may be severe)||Bronchospasm (severe if IV so this route is contraindicated)|
|CVS||↑ HR, ↓ BP following boluses||↑ SVR, ↑ BP (may cause, ↓ HR) coronary vasoconstriction||↑ BP|
|CNS||Headache, nausea, comiting||Headache, nausea||Nausea, vomiting|
|Renal||↓ UO due to ADH-like effects with prolonged infusions|
|GU||↑ Uterine tone (↑ frequency at low dose, tetanic contraction at high dose), foetal distress, lactation||↑ Uterine contraction frequency and tone|
|Other||May be metabolised by oxytocinases in blood products if coadministered on the same line||Contraindicated in pre-eclampsia due to HTN|
- Peck TE, Hill SA. Pharmacology for Anaesthesia and Intensive Care. 4th Ed. Cambridge University Press. 2014.
- Petkov V. Essential Pharmacology For The ANZCA Primary Examination. Vesselin Petkov. 2012.
- Smith S, Scarth E, Sasada M. Drugs in Anaesthesia and Intensive Care. 4th Ed. Oxford University Press. 2011.