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SYNTOCINON 10 IU/ML CONCENTRATE FOR SOLUTION FOR INFUSION

Active substance: OXYTOCIN

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SUMMARY OF PRODUCT CHARACTERISTICS

1

NAME OF THE MEDICINAL PRODUCT

Syntocinon® 10 IU/ml Concentrate for solution for infusion

2.

QUALITATIVE AND QUANTITATIVE COMPOSITION
Oxytocin.
Concentrate for solution for infusion (in 1 mL ampoule) containing 10 IU/mL.
Excipient(s) with known effect:
Ethanol 5.000mg
For the full list of excipients, see section 6.1.

3.

PHARMACEUTICAL FORM
Concentrate for solution for infusion.
A clear, colourless, sterile solution in 1ml clear glass ampoules.

4.

CLINICAL PARTICULARS

4.1.

Therapeutic indications
Antepartum
• Induction of labour for medical reasons, e.g. in cases of post-term gestation,
premature rupture of the membranes, pregnancy-induced hypertension (preeclampsia)
• Stimulation of labour in hypotonic uterine inertia
• Early stages of pregnancy as adjunctive therapy for the management of
incomplete, inevitable, or missed abortion.
Postpartum
• During caesarean section, but following delivery of the child
• Prevention and treatment of postpartum uterine atony and haemorrhage

4.2.

Posology and method of administration

Induction or enhancement of labour: Oxytocin should not be started for 6 hours
following administration of vaginal prostaglandins. Syntocinon should be
administered as an intravenous (i.v.) drip infusion or, preferably, by means of a
variable-speed infusion pump. For drip infusion it is recommended that 5 IU of
Syntocinon be added to 500ml of a physiological electrolyte solution (such as sodium
chloride 0.9%). For patients in whom infusion of sodium chloride must be avoided,
5% dextrose solution may be used as the diluent (see Section 4.4 “Special warnings
and precautions for use”). To ensure even mixing, the bottle or bag must be turned
upside down several times before use.
The initial infusion rate should be set at 1 to 4 milliunits/minute (2 to 8 drops/minute).
It may be gradually increased at intervals not shorter than 20 minutes and increments
of not more than 1-2 milliunits/minute, until a contraction pattern similar to that of
normal labour is established. In pregnancy near term this can often be achieved with
an infusion of less than 10 milliunits/minute (20 drops/minute), and the recommended
maximum rate is 20 milliunits/minute (40 drops/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 Syntocinon solution,
e.g., 10 IU in 500ml.
When using a motor-driven infusion pump which delivers smaller volumes than those
given by drip infusion, the concentration suitable for infusion within the
recommended dosage range must be calculated according to the specifications of the
pump.
The frequency, strength, and duration of contractions as well as the foetal heart rate
must be carefully monitored throughout the infusion. Once an adequate level of
uterine activity is attained, aiming for 3 to 4 contractions every 10 minutes, the
infusion rate can often be reduced. In the event of uterine hyperactivity and/or foetal
distress, the infusion must be discontinued immediately.
If, in women who are at term or near term, regular contractions are not established
after the infusion of a total amount of 5 IU, it is recommended that the attempt to
induce labour be ceased; it may be repeated on the following day, starting again from
a rate of 1 to 4 milliunits/minute (see Section 4.3 “Contra-indications”).
Incomplete, inevitable, or missed abortion: 5 IU by i.v. infusion (5 IU diluted in
physiological electrolyte solution and administered as an i.v. drip infusion or,
preferably, by means of a variable-speed infusion pump over 5 minutes), if necessary
followed by i.v. infusion at a rate of 20 to 40 milliunits/minute.
Caesarean section: 5 IU by i.v. infusion (5 IU diluted in physiological electrolyte
solution and administered as an i.v. drip infusion or, preferably, by means of a
variable-speed infusion pump over 5 minutes) immediately after delivery.
Prevention of postpartum uterine haemorrhage: The usual dose is 5 IU by i.v.
infusion (5 IU diluted in physiological electrolyte solution and administered as an i.v.
drip infusion or, preferably, by means of a variable-speed infusion pump over 5
minutes) after delivery of the placenta. In women given Syntocinon 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.
Treatment of postpartum uterine haemorrhage: 5 IU by i.v. infusion (5 IU diluted in
physiological electrolyte solution and administered as an i.v. drip infusion or,

preferably, by means of a variable-speed infusion pump over 5 minutes), followed in
severe cases by i.v. infusion of a solution containing 5 to 20 IU of oxytocin in 500ml
of an electrolyte-containing diluent, run at the rate necessary to control uterine atony.
Route of administration: Intravenous infusion.
Special populations
Renal impairment
No studies have been performed in renally impaired patients.
Hepatic impairment
No studies have been performed in hepatically impaired patients.
Paediatric population
No studies have been performed in paediatric patients.
Elderly population
No studies have been performed in elderly patients (65 years old and over).

4.3.

Contraindications



Hypersensitivity to the active substance or to any of the excipients listed in
section 6.1
Hypertonic uterine contractions, mechanical obstruction to delivery, foetal
distress.

Any condition in which, for foetal or maternal reasons, spontaneous labour is
inadvisable and/or vaginal delivery is contra-indicated: e.g.:
• Significant cephalopelvic disproportion
• Foetal malpresentation
• Placenta praevia and vasa praevia
• Placental abruption
• Cord presentation or prolapse
• Overdistension or impaired resistance of the uterus to rupture as in multiple
pregnancy
• Polyhydramnios
• Grand multiparity
• In the presence of a uterine scar resulting from major surgery including classical
caesarean section.
Syntocinon should not be used for prolonged periods in patients with oxytocinresistant uterine inertia, severe pre-eclamptic toxaemia or severe cardiovascular
disorders.
Syntocinon must not be administered within 6 hours after vaginal prostaglandins have
been given (see section 4.5 Interaction with other medicinal products and other forms
of interaction).

4.4.

Special warnings and precautions for use

Syntocinon must only be administered as an i.v. infusion and never by i.v. bolus
injection as it may cause an acute short-lasting hypotension accompanied with
flushing and reflex tachycardia.
Induction of labour
The induction of labour by means of oxytocin should be attempted only when strictly
indicated for medical reasons. Administration should only be under hospital
conditions and qualified medical supervision.
Cardiovascular disorders
Syntocinon should be used with caution in patients who have a pre-disposition to
myocardial ischaemia due to pre-existing cardiovascular disease (such as
hypertrophic cardiomyopathy, valvular heart disease and/or ischaemic heart disease
including coronary artery vasospasm), to avoid significant changes in blood pressure
and heart rate in these patients.
QT Syndrome
Syntocinon should be given with caution to patients with known ‘long QT syndrome’
or related symptoms and to patients taking drugs that are known to prolong the QTc
interval (see section 4.5 Interaction with other medicinal products and other forms of
interaction).
When Syntocinon is given for induction and enhancement of labour:
• Foetal distress and foetal death: Administration of oxytocin at excessive doses
results in uterine overstimulation which may cause foetal distress, asphyxia and
death, or may lead to hypertonicity, tetanic contractions or rupture of the uterus.
Careful monitoring of foetal heart rate and uterine motility (frequency, strength,
and duration of contractions) is essential, so that the dosage may be adjusted to
individual response.
• Particular caution is required in the presence of borderline cephalopelvic
disproportion, secondary uterine inertia, mild or moderate degrees of pregnancyinduced hypertension or cardiac disease, and in patients above 35 years of age or
with a history of lower-uterine-segment caesarean section.
• Disseminated intravascular coagulation: In rare circumstances, the
pharmacological induction of labour using uterotonic agents, including oxytocin
increases the risk of post partum disseminated intravascular coagulation (DIC).
The pharmacological induction itself and not a particular agent is linked to such
risk. This risk is increased in particular if the woman has additional risk factors
for DIC such as being 35 years of age or over, complications during pregnancy
and gestational age more than 40 weeks. In these women, oxytocin or any other
alternative drug should be used with care, and the practitioner should be alerted
by signs of DIC.
Intrauterine death
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.
Water intoxication
Because oxytocin possesses slight antidiuretic activity, its prolonged i.v.
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. The combined antidiuretic effect of oxytocin and the i.v. fluid
administration may cause fluid overload leading to a haemodynamic form of acute
pulmonary oedema without hyponatraemia. To avoid these rare complications, the
following precautions must be observed whenever high doses of oxytocin are
administered over a long time: an electrolyte-containing diluent must be used (not
dextrose); the volume of infused fluid should be kept low (by infusing oxytocin at a
higher concentration than recommended for the induction or enhancement of labour at
term); fluid intake by mouth must be restricted; a fluid balance chart should be kept,
and serum electrolytes should be measured when electrolyte imbalance is suspected.
Caution should be exercised in patients with severe renal impairment because of
possible water retention and possible accumulation of oxytocin (see section 5.2
Pharmacokinetics).

4.5.

Interaction with other medicinal products and other forms of interaction
Interaction resulting in a concomitant use not recommended
Prostaglandins and their analogues
Prostaglandins and its analogues facilitate contraction of the myometrium hence
oxytocin can potentiate the uterine action of prostaglandins and analogues and vice
versa (see section 4.3 Contraindications).
Drugs prolonging the QT interval
Oxytocin should be considered as potentially arrhythmogenic, particularly in patients
with other risk factors for Torsades de Pointes such as drugs which prolong the QT
interval or in patients with history of long QT syndrome (see section 4.4 Special
warnings and precautions for use).
Interactions to be considered
Inhalation anaesthetics
Inhalation anaesthetics (e.g. cyclopropane, halothane, sevoflurane, desflurane) have a
relaxing effect on the uterus and produce a notable inhibition of uterine tone and
thereby, may diminish the uterotonic effect of oxytocin. Their concurrent use with
oxytocin has also been reported to cause cardiac rhythm disturbances.
Vasoconstrictors/Sympathomimetics
Oxytocin may enhance the vasopressor effects of vasoconstrictors and
sympathomimetics, even those contained in local anaesthetics.
Caudal anaesthetics
When given during or after caudal block anaesthesia, oxytocin may potentiate the
pressor effect of sympathomimetic vasoconstrictor agents.

4.6.

Fertility, pregnancy and lactation
Animal reproduction studies have not been conducted with oxytocin. Based on the
wide experience with this drug and its chemical structure and pharmacological

properties, it is not expected to present a risk of foetal abnormalities when used as
indicated.
Oxytocin may be found in small quantities in mother’s breast milk. However,
oxytocin is not expected to cause harmful effects in the newborn because it passes
into the alimentary tract where it undergoes rapid inactivation.

4.7

Effects on ability to drive and use machines
Syntocinon can induce labour, therefore caution should be exercised when
driving or operating machines. Women with uterine contractions should not
drive or use machines.

4.8.

Undesirable effects
As there is a wide variation in uterine sensitivity, uterine spasm may be caused in
some instances by what are normally considered to be low doses. When oxytocin is
used by i.v. infusion for the induction or enhancement of labour, administration at too
high doses results in uterine overstimulation which may cause foetal distress,
asphyxia, and death, or may lead to hypertonicity, tetanic contractions, soft tissue
damage or rupture of the uterus.
Rapid i.v. bolus injection of oxytocin at doses amounting to several IU may result in
acute short-lasting hypotension accompanied with flushing and reflex tachycardia
(see section 4.4 Special warnings and precautions for use). These rapid
haemodynamic changes may result in myocardial ischaemia, particularly in patients
with pre-existing cardiovascular disease. Rapid i.v. bolus injection of oxytocin at
doses amounting to several IU may also lead to QTc prolongation.
In rare circumstances the pharmacological induction of labour using uterotonic
agents, including oxytocin, increases the risk of postpartum disseminated
intravascular coagulation (see section 4.4 Special warnings and precautions for use).
Water intoxication
Water intoxication associated with maternal and neonatal hyponatraemia has been
reported in cases where high doses of oxytocin together with large amounts of
electrolyte-free fluid have been administered over a prolonged period of time (see
Section 4.4 “Special warnings and precautions for use”). The combined antidiuretic
effect of oxytocin and the i.v. fluid administration may cause fluid overload leading to
a haemodynamic form of acute pulmonary oedema without hyponatraemia (see
section 4.4. Special warnings and precautions for use).
Symptoms of water intoxication include:
1. Headache, anorexia, nausea, vomiting and abdominal pain.
2. Lethargy, drowsiness, unconsciousness and grand-mal type seizures.
3. Low blood electrolyte concentration.
Undesirable effects (Tables 1 and 2) are ranked under heading of frequency, the most
frequent first, using the following convention: very common ( 1/10); common (
1/100, < 1/10); uncommon ( 1/1,000, < 1/100); rare ( 1/10,000, < 1/1,000); very
rare (< 1/10,000), including isolated reports; not known (cannot be estimated from the
available data).The ADRs tabulated below are based on clinical trial results as well as
postmarketing reports.









The adverse drug reactions derived from post-marketing experience with Syntocinon
are via spontaneous case reports and literature cases. Because these reactions are
reported voluntarily from a population of uncertain size, it is not possible to reliably
estimate their frequency which is therefore categorised as not known. Adverse drug
reactions are listed according to system organ classes in MedDRA. Within each
system organ class, ADRs are presented in order of decreasing seriousness.
Table 1 Adverse drug reactions in mother
System organ class
Immune system disorders
Nervous system disorders
Cardiac disorders

Vascular disorders
Gastrointestinal disorders
Skin and subcutaneous tissue
disorders
Pregnancy, puerperium and
perinatal conditions
Metabolism and nutrition disorders
Respiratory, thoracic and
mediastinal disorders
General disorders and
administration site conditions
Blood and lymphatic system
disorders

Adverse drug reaction
Rare: Anaphylactoid reaction associated with
dyspnoea, hypotension or Shock
Common: Headache
Common Tachycardia, bradycardia
Uncommon: Arrhythmia
Not known: Myocardial ischaemia,
QTc prolongation
Not known: Hypotension, haemorrhage
Common: Nausea, vomiting
Rare: Rash
Not known: Uterine hypertonicity, tetanic
contractions, rupture of the uterus
Not known: Water intoxication, maternal
hyponatraemia
Not known: acute pulmonary oedema
Not known: Flushing
Not known: disseminated intravascular
coagulation

Table 1 Adverse drug reactions in foetus/neonate
System organ class
Pregnancy, puerperium and
perinatal conditions
Metabolism and nutrition disorders

4.9.

Adverse drug reaction
Not known: foetal distress, asphyxia and
death
Not known: Neonatal hyponatraemia

Overdose
The fatal dose of Syntocinon has not been established. Syntocinon is subject to
inactivation by proteolytic enzymes of the alimentary tract. Hence it is not absorbed
from the intestine and is not likely to have toxic effects when ingested.
The symptoms and consequences of overdosage are those mentioned under sections
4.4 “Special warnings and precautions for use” and 4.8 “Undesirable effects”. In
addition, as a result of uterine overstimulation, placental abruption and/or amniotic
fluid embolism have been reported.

Treatment: When signs or symptoms of overdosage occur during continuous i.v.
administration of Syntocinon, the infusion must be discontinued at once and oxygen
should be given to the mother. In cases of water intoxication it is essential to restrict
fluid intake, promote diuresis, correct electrolyte imbalance, and control convulsions
that may eventually occur. In the case of coma, a free airway should be maintained
with routine measures normally employed in the nursing of the unconscious patient.

5.

PHARMACOLOGICAL PROPERTIES

5.1.

Pharmacodynamic properties
Pharmacotherapeutic group: Posterior pituitary lobe hormones
ATC code: H01B B02
Mechanism of action
Oxytocin is a cyclic nonapeptide that is obtained by chemical synthesis. This
synthetic form is identical to the natural hormone that is stored in the posterior
pituitary and released into the systemic circulation in response to suckling and labour.
Oxytocin stimulates the smooth muscle of the uterus, more powerfully towards the
end of pregnancy, during labour, and immediately postpartum. At these times, the
oxytocin receptors in the myometrium are increased.
The oxytocin receptors are G-proteins coupled receptors. Activation of receptor by
oxytocin triggers release of calcium from intracellular stores and thus leads to
myometrial contraction.
Oxytocin elicits rhythmic contractions in upper segment of uterus, similar in
frequency, force and duration to those observed during labour.
Being synthetic, oxytocin in Syntocinon does not contain vasopressin, but even in its
pure form oxytocin possesses some weak intrinsic vasopressin-like antidiuretic
activity.
Based on in vitro studies, prolonged exposure of oxytocin had been reported to cause
desensitisation of oxytocin receptors probably due to down-regulation of oxytocinbinding sites, destabilisation of oxytocin receptors mRNA and internalisation of
oxytocin receptors.
Plasma levels and onset/duration of effect
Intravenous infusion. When Syntocinon is given by continuous i.v. infusion at doses
appropriate for induction or enhancement of labour, the uterine response sets in
gradually and usually reaches a steady state within 20 to 40 minutes. The
corresponding plasma levels of oxytocin are comparable to those measured during
spontaneous first-stage labour. For example, oxytocin plasma levels in 10 pregnant
women at term receiving a 4 milliunits per minute intravenous infusion were 2 to 5
microunits/mL. Upon discontinuation of the infusion, or following a substantial
reduction in the infusion rate, e.g. in the event of overstimulation, uterine activity
declines rapidly but may continue at an adequate lower level.

5.2.

Pharmacokinetic properties

Absorption
Plasma levels of oxytocin following intravenous infusion at 4 milliunits per minute in
pregnant women at term were 2 to 5 microunits/mL.
Distribution
The steady-state volume of distribution determined in 6 healthy men after i.v.
injection is 12.2 L or 0.17 L/kg. Plasma protein binding is negligible for oxytocin. It
crosses the placenta in both directions. Oxytocin may be found in small quantities in
mother’s breast milk.
Biotransformation/Metabolism
Oxytocinase is a glycoprotein aminopeptidase that is produced during pregnancy and
appears in the plasma. It is capable of degrading oxytocin. It is produced from both
the mother and the foetus. Liver and kidney plays a major role in metabolising and
clearing oxytocin from the plasma. Thus, liver, kidney and systemic circulation
contribute to the biotransformation of oxytocin.
Elimination
Plasma half-life of oxytocin ranges from 3 to 20 min. The metabolites are excreted in
urine whereas less than 1% of the oxytocin is excreted unchanged in urine. The
metabolic clearance rate amounts to 20 mL/kg/ min in the pregnant woman.
Renal impairment
No studies have been performed in renally impaired patients. However, considering
the excretion of oxytocin and its reduced urinary excretion because of anti-diuretic
properties, the possible accumulation of oxytocin can result in prolonged action.
Hepatic impairment
No studies have been performed in hepatically impaired patients. Pharmacokinetic
alteration in patients with impaired hepatic function is unlikely since metabolising
enzyme, oxytocinase, is not confined to liver alone and the oxytocinase levels in
placenta during the term has significantly increased. Therefore, biotransformation of
oxytocin in impaired hepatic function may not result in substantial changes in
metabolic clearance of oxytocin.

5.3.

Preclinical safety data
Pre-clinical data for oxytocin reveal no special hazard for humans based on
conventional studies of single dose acute toxicity, genotoxicity, and mutagenicity.

6

PHARMACEUTICAL PARTICULARS

6.1

List of excipients
Sodium acetate tri-hydrate, acetic acid, chlorobutanol, ethanol and water for
injections.

6.2

Incompatibilities
Syntocinon should not be infused via the same apparatus as blood or plasma,
because the peptide linkages are rapidly inactivated by oxytocin-inactivating

enzymes. Syntocinon is incompatible with solutions containing sodium
metabisulphite as a stabiliser.
6.3

Shelf life
Five years

6.4

Special precautions for storage
Store between 2ºC and 8ºC. May be stored up to 30ºC for 3 months, but must
then be discarded.

6.5

Nature and contents of container
Clear glass 1ml ampoules. Boxes of 5 ampoules.

6.6.

Special precautions for disposal and other handling
Snap ampoules: no file required.
Syntocinon is compatible with the following infusion fluids, but due attention should
be paid to the advisability of using electrolyte fluids in individual patients:
sodium/potassium chloride (103mmol Na+ and 51mmol K+), sodium bicarbonate
1.39%, sodium chloride 0.9%, sodium lactate 1.72%, dextrose 5%, laevulose 20%,
macrodex 6%, rheomacrodex 10%, Ringer’s solution.

7

MARKETING AUTHORISATION HOLDER
Alliance Pharmaceuticals Ltd
Avonbridge House
Bath Road
Chippenham
Wiltshire
SN15 2BB

8

MARKETING AUTHORISATION NUMBER(S)
PL 16853/0020

9

DATE OF FIRST AUTHORISATION/RENEWAL OF THE
AUTHORISATION
22/03/2005

10

DATE OF REVISION OF THE TEXT

22/02/2013

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Source: Medicines and Healthcare Products Regulatory Agency

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