OXYTOCIN

Synthetic oxytocic medicine; causes the uterus to contract

Dosage Forms

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Injection

10 IU/ml

Uses

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  • Induction of labour
  • Prevention and treatment of postpartum haemorrhage or excessive bleeding after abortion

Dose and Duration

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Induction of labour

→ Initially, dissolve 2.5 IU in 500 ml of normal saline and infuse at 10 drops per minute.

→ Then, increase infusion rate by 10 drops per minute every 30 minutes until a good contraction pattern is reached (3–4 contractions every 10 minutes, each lasting >40 seconds). Maintain this rate until delivery is completed.

→ Maximum infusion rate is 60 drops per minute.

If good contraction pattern is not established at a rate of 60 drops per minute:

→ Increase oxytocin concentration to 5 IU in 500 ml of normal saline and adjust infusion rate to 30 drops per minute. Then, increase infusion rate by 10 drops per minute every 30 minutes until a good contraction pattern is reached; maximum 60 drops per minute.

If good contraction pattern is not established using higher concentration:

In multigravida women and women with previous caesarean scars refer for delivery by C-section.

In primigravida women: Infuse oxytocin at a higher concentration of 10 IU in 500ml. If good contractions are not there at this rate, refer for delivery by C-section.

Monitor foetal heart rate and uterine contractions.

If uterine hyperactivity or foetal distress occurs, discontinue immediately.

Prevention of postpartum haemorrhage

10 IU by slow IV injection or IM single dose when the anterior shoulder is delivered or immediately after birth.

Treatment of postpartum haemorrhage

10–40 IU by slow IV injection as a single dose.

Preparation

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  • Preferably use 0.9% sodium chloride (not glucose) to give the infusion to avoid water overload and low blood sodium levels (electrolyte disturbances).

Contraindications

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  • Hypertonic uterine contractions
  • Mechanical obstruction to delivery
  • Foetal distress
  • Conditions where spontaneous labour or vaginal delivery is not recommended
  • Severe eclampsia
  • Severe heart disease
  • Foetus with big head
  • Small maternal pelvis
  • Severe hypertension

Side Effects

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  • Uncontrolled uterine contractions, uterine rupture
  • Nausea and vomiting
  • Irregular heartbeat
  • Foetal distress

Interactions

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  • Misoprostol (increased contractions)

Pregnancy

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  • Can be used

Breast-feeding

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  • Can be used

Storage

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  • Store at 2–8°C. Do not freeze

⚠️ Caution

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  • If vaginal misoprostol had been given, do not give oxytocin until at least 8 hours have passed
  • Effective dose varies for different women
  • If foetal heart rate is < 100 beats per minute, stop infusion and manage for foetal distress
  • If hyperactivity of uterus occurs (any contraction lasting > 60 seconds or > 4 contractions in 10 minutes), stop infusion and relax uterus using IV salbutamol
  • Do not use oxytocin concentration of 10 IU in 500ml in multigravida and women with previous C-section
  • Women using oxytocin should never be left alone
  • Oxytocin is preferable to ergometrine as it produces more controlled contractions
  • Avoid prolonged use in oxytocin-resistant uterine inactivity
  • Avoid IV bolus injection during labour. Give only by IV infusion