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Combination of
OxytocinHypothalamic hormone
ErgometrineErgot alkaloid
Clinical data
Routes of
Intramuscular injection
Legal status
Legal status
  • In general: ℞ (Prescription only)
CAS Number
PubChem CID

Oxytocin/ergometrine (trade name Syntometrine) is an obstetric combination drug. The components are synthetically produced oxytocin, a human hormone produced in the hypothalamus, and ergometrine, an alpha-adrenergic, dopaminergic and serotonin (5-HT2) receptor agonist.

Both substances cause the uterus to contract. An injection of Syntometrine is given in the third stage of labor, just after the birth of the child to facilitate delivery of the placenta[1] and to prevent postpartum hemorrhage[1] by causing smooth muscle tissue in the blood vessel walls to narrow, thereby reducing blood flow.


Syntometrine should not be used in patients with:

It should be used with caution in patients with:

Side effects[edit]

Possible side effects include:

A health care provider should be notified immediately if there are any side effects. They may be signs of allergy or of too much fluid associated with high doses or long infusions.[2]

Drug interactions[edit]

Prostaglandins increase the effect of oxytocin and vice versa. The contractions should be carefully monitored if oxytocin is given after a prostaglandin dose.

Syntometrine may enhance the blood pressure raising effect of vasoconstrictors (medicines given to constrict the blood vessels).

Some inhaled anaesthetics used for general anesthesia, such as cyclopropane and halothane, may reduce the effect of oxytocin and ergometrine. There may also be an increased risk of a drop in blood pressure and abnormal heart beats if oxytocin is given with these general anesthetics.


  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab NetDoctor.co.uk > Syntometrine Last updated 15.9.2005
  2. ^ a b c d e f g h i j The Better Health Channel website by the Victorian Government, Australia > Syntometrine(R) This leaflet was prepared in March 2009