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||Severe PPH||Severe PPH|
|Presentation||Clear liquid at 5-10 U.ml-1||Clear liquid at 250μg.ml-1, up to 8 doses (2mg)|
|Route of Administration||IV||IV, IM||Intramyometrial injection, IM||Intramyometrial, IM|
|Dosing||1.5-12mU.min-1||250μg IM (IV in emergency via slow push)||500μg IM|
|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)||Bronchospasm, APO due to ↑ PVR with subsequent hypoxia|
|CVS||↑ HR, ↓ BP following boluses||↑ SVR, ↑ BP (may cause, ↓ HR) coronary vasoconstriction||↑ SVR, ↑ BP||↑ SVR, ↑ BP (usually transient)|
|CNS||Headache, nausea, vomiting||Headache, nausea||Nausea, vomiting||Headache|
|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||↑ Uterine contraction frequency and tone||↑ Uterine contraction frequency and tone, contraindicated in pelvic inflammatory disease|
|Other||May be metabolised by oxytocinases in blood products if coadministered on the same line||Contraindicated in pre-eclampsia due to HTN||Deprecated by carboprost, increased body temperature|
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- Smith S, Scarth E, Sasada M. Drugs in Anaesthesia and Intensive Care. 4th Ed. Oxford University Press. 2011.
- Royal Women's Hospita. Postpartum Haemorrhage - Carboprost. 2017.