Oxytocin parenteral
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Parenteral formulations of oxytocin.
Drugs List
Therapeutic Indications
Uses
Incomplete, inevitable or missed abortion
Labour - augmentation of
Labour - induction of
Postpartum haemorrhage: Prevention
Postpartum haemorrhage: Treatment
Prevention of uterine atony after Caesarean section
Dosage
Adults
Induction or enhancement of labour
Oxytocin should not be administered within 6 hours of vaginal prostaglandin administration.
Administer 5 units of oxytocin in 500ml of a physiological electrolyte solution infused at an initial rate of 0.001 to 0.004 units per minute (1 to 4 milliUnit per minute). Gradually increase the rate by 0.001 to 0.002 units per minute (1 to 2 milliUnit per minute) at intervals of not less than 20 minutes until a contraction pattern similar to that of normal labour is established.
In pregnancy near term, an infusion rate of less than 0.01 units per minute (10 milliUnits per minute) is usually sufficient.
The recommended maximum rate is 0.02 units per minute (20 milliUnits per minute).
In the unusual event that higher rates are required, as may occur in the management of foetal death in utero or for induction of labour at an earlier stage of pregnancy, when the uterus is less sensitive to oxytocin, it is advisable to use a more concentrated oxytocin solution such as 10 units in 500ml.
Once an adequate level of uterine activity is attained (3 to 4 contractions every 10 minutes), the infusion rate can often be reduced.
If regular contractions in women at or near term are not established after the infusion of a total amount of 5 units, it is recommended that the attempt to induce labour be ceased. It may be repeated on the following day starting again at an initial infusion rate of 0.001 to 0.004 units per minute (1 to 4 milliUnit per minute).
Caesarean section
Administer 5 units by intravenous infusion over 5 minutes immediately after delivery. Alternatively, can be administered by slow intravenous injection immediately after delivery.
Prevention of postpartum uterine haemorrhage
The usual dose is 5 units by intravenous infusion over 5 minutes after delivery of the placenta. Alternatively, can be administered by slow intravenous injection.
In women given oxytocin for induction or enhancement of labour, the infusion should be continued at an increased rate during the third stage of labour and for the next few hours thereafter.
The following unlicensed dose of 10 units by intramuscular injection may be used in place of oxytocin and ergometrine.
Treatment of postpartum uterine haemorrhage
Administer 5 units by intravenous infusion over 5 minutes followed, in severe cases, by intravenous infusion of a solution containing 5 to 20 units of oxytocin in 500ml of an electrolyte containing diluent, run at the rate necessary to control uterine atony.
Alternatively administer 5 units by slow intravenous injection, repeated if necessary.
In severe cases, a dose of 40 units in 500ml infusion fluid by intravenous infusion may be administered, run at the rate necessary to control uterine atony.
Incomplete, inevitable or missed abortion
Administer 5 units by intravenous infusion over 5 minutes followed, if necessary, by a rate of 0.02 to 0.04 units per minute (20 to 40 milliUnits per minute).
Alternatively 5 units can be administered by slow intravenous injection, if necessary followed by intravenous infusion at a rate of 20 to 40mU/min or higher.
Administration
For intravenous infusion. May also be administered by slow intravenous injection.
Oxytocin should be administered as an intravenous drip infusion or, preferably, by means of a variable-speed infusion pump.
If ergometrine is inappropriate for the prevention of haemorrhage, oxytocin may be given by the unlicensed route of intramuscular injection.
Contraindications
Conditions where spontaneous labour or vaginal delivery inadvisable
Hypersensitivity to latex
Foetal distress
Hypertonic uterine contractions
Long QT syndrome
Severe cardiovascular disorder
Severe pre-eclampsia
Torsade de pointes
Precautions and Warnings
Children under 18 years
Family history of long QT syndrome
Females over 35 years
Previous Caesarean section
Cardiac disorder
Cephalopelvic disproportion
Electrolyte imbalance
History of torsade de pointes
Hypervolaemia
Pregnancy-induced hypertension
Secondary uterine inertia
Severe renal impairment
Correct electrolyte disorders before treatment
Latex allergy may predispose patient to severe allergic reaction
Not all available brands are licensed for all routes of administration
Treatment to be initiated by specialist
High doses in large volumes may cause water intoxication/hyponatraemia
Rapid intravenous administration may cause acute short-lasting hypotension
Consider monitoring ECG in patients at risk of QT prolongation
Monitor serum electrolytes
Monitor uterine contractions and foetal heart rate
Pregnancy: Monitor for disseminated intravascular coagulation postpartum
Discontinue if uterine hyperactivity and/or foetal distress occurs
Excessive dosing of oxytocin results in uterine overstimulation, which may lead to hypertonicity, tetanic contractions, uterine rupture, or foetal distress, asphyxia or death. In the event of uterine hyperactivity and/or foetal distress, discontinue immediately.
The induction of labour using uterotonic agents, increases the risk of disseminated intravascular coagulation (DIC). This risk is increased in women aged 35 or older, those who experienced a complicated pregnancy and a gestational age of more than 40 weeks. Women with these additional risk factors should be treated with caution and the physician should look for signs of disseminated intravascular coagulation.
In the case of foetal death in utero and/or in the presence of meconium-stained amniotic fluid, tumultuous labour must be avoided as it may cause amniotic fluid embolism.
Oxytocin possesses slight antidiuretic activity so its prolonged intravenous administration at high doses in conjunction with large volumes of fluid, as may be the case in the treatment of inevitable or missed abortion or in the management of postpartum haemorrhage, may cause water intoxication associated with hyponatraemia.
Use with caution in patients with severe renal impairment because of possible water retention and possible accumulation of oxytocin.
Latex allergy or intolerance may be an important predisposing risk factor for anaphylaxis following oxytocin administration.
Pregnancy and Lactation
Pregnancy
Oxytocin is indicated for use during pregnancy.
Oxytocin is not expected to present a risk of foetal abnormalities when used as recommended.
Animal reproductive studies have not been conducted with oxytocin.
Lactation
Oxytocin is found in small amounts in human breast milk.
Oxytocin is not expected to cause harmful effects in the neonate as it passes into the alimentary tract and undergoes rapid inactivation.
Side Effects
Abdominal pain
Anaphylactic reaction
Anaphylactoid reaction
Angioedema
Anorexia
Bradycardia
Cardiac arrhythmias
Drowsiness
Dyspnoea
Electrolyte disturbances
Flushing
Foetal asphyxiation
Foetal death
Foetal distress
Haemorrhage
Headache
Hyponatraemia
Hypotension
Intravascular coagulation (disseminated)
Lethargy
Myocardial ischaemia
Nausea
Neonatal hyponatraemia
Prolongation of QT interval
Pulmonary oedema
Rash
Reflex tachycardia
Seizures
Shock
Tachycardia
Tissue damage
Unconsciousness
Uterine contractions (severe)
Uterine hypertonus
Uterine rupture
Uterine spasm
Vomiting
Water intoxication
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: July 2018
Reference Sources
Summary of Product Characteristics: Oxytocin 5 IU/ml solution for injection. EVER Valinject Pharma GmbH Ltd. Revised June 2018.
Summary of Product Characteristics: Oxytocin 10 IU/ml solution for injection. EVER Valinject Pharma GmbH Ltd. Revised June 2018.
Summary of Product Characteristics: Oxytocin 10 IU/ml concentrate for solution for infusion. Wockhardt UK Ltd. Revised November 2017.
Summary of Product Characteristics: Syntocinon 5 IU/ml concentrate for solution for infusion. Novartis Pharmaceuticals UK Ltd. Revised May 2018.
Summary of Product Characteristics: Syntocinon 10 IU/ml concentrate for solution for infusion. Novartis Pharmaceuticals UK Ltd. Revised May 2018.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 09 July 18
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