Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Oxytocin 10 IU/ml Solution for infusion
⚠ This medicine appears to have been discontinued
The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.
If you were prescribed this medicine, other products containing Oxytocin may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.
What it is and what it is used for
for
Oxytocin 10 IU/ml Solution for infusion contains a manufactured form of oxytocin (a natural hormone). It belongs to a group of medicines called oxytocics that makes the muscles of the womb contract. Oxytocin is used: ▪ to start or help contractions during childbirth (labour); ▪ to help in the management of a miscarriage; ▪ during a caesarean section; ▪ to prevent and control bleeding after delivery of your baby. 2.
What you need to know before you take it
e Oxytocin
You must not receive Oxytocin:
- if you are allergic to oxytocin or any of the other ingredients of this medicine (listed in section 6);
- if your doctor thinks that to start or increase contractions of the womb would be unsuitable for you, for example:
- where contractions of the womb are unusually strong;
- where there are obstructions that may prevent delivery;
- where your baby may be short of oxygen;
- where labour or vaginal delivery is not advisable, for example:
- if your baby's head is too large to fit through your pelvis;
- if your baby is wrongly positioned in the birth canal;
- if the placenta lies near or over the neck of your womb;
May 2024
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- if your baby lacks oxygen due to blood vessels running across the neck of your womb;
- if the placenta separates from the womb before the baby is born;
- if there are one or more loops of umbilical cord between the baby and the neck of the womb, either before or after your waters break;
- if your womb is over-extended and more likely to tear, for example if you are carrying more than one baby or have too much water (amniotic fluid) in your womb;
- if you have had five or more pregnancies in the past or if your womb is scarred by previous caesarean section or other surgery; if you have been given medicines called prostaglandins (used to bring on labour or treat stomach ulcers). Oxytocin should not be used for 6 hours after vaginal prostaglandins as the effects of both medicines may be increased.
Oxytocin should not be used for prolonged periods if: ▪ your contractions do not increase with the treatment; ▪ you have a condition known as severe pre-eclamptic toxaemia (high blood pressure, protein in the urine and swelling); ▪ you have severe problems with your heart or blood circulation. Warnings and precautions Oxytocin should only be administered by a healthcare professional in a hospital setting. Oxytocin should not be given as rapid injection into a vein as this may cause decreased blood pressure, a sudden brief sensation of heat (often over the entire body), and an increased heart rate. Talk to your doctor or midwife before you receive Oxytocin if: ▪ you are prone to chest pain due to pre-existing heart and/or circulation problems; ▪ you have a known irregular heart beat ('long QT syndrome') or related symptoms, or are taking medicines known to cause the syndrome (see section 'Other medicines and Oxytocin'); ▪ you have had a previous caesarean section; ▪ you are more than 35 years old; ▪ you have raised blood pressure or heart problems; ▪ your womb was contracting strongly but has now begun to contract less strongly; ▪ you have been told by a doctor or midwife that normal delivery may be difficult for you due to the small size of your pelvis; ▪ you have kidney problems, as Oxytocin can cause water retention; ▪ you have had complications during your pregnancy; ▪ you are more than 40 weeks pregnant. When Oxytocin is given to induce and enhance labour, the infusion rate should be set to maintain a contraction pattern similar to normal labour and adjusted to individual response. Too high doses may cause very strong continuous contractions and possibly tearing of the womb, with serious complications for you and your baby. Oxytocin may rarely cause disseminated intravascular coagulation which causes symptoms including abnormal blood clotting, bleeding and anaemia.
May 2024
High doses of Oxytocin may force amniotic fluid from your womb into your blood. This is known as amniotic fluid embolism. Large doses of Oxytocin over a long period of time, whilst drinking or receiving large volumes of fluid may make your stomach feel very full, cause difficulty in breathing and lower salt levels in your blood. If any of the above applies to you, or if you are not sure, speak to your doctor or midwife before you receive Oxytocin. Latex allergy The active substance in Oxytocin 10 IU/ml Solution for infusion might cause a severe allergic reaction (anaphylaxis) in patients with latex allergy. Please tell your doctor if you know you are allergic to latex. Other medicines and Oxytocin Tell your doctor or midwife if you are taking or have recently taken any of the following medicines as they may interfere with Oxytocin: ▪ prostaglandins (used to start labour or to treat stomach ulcers) and similar drugs as the effects of both drugs may be increased; ▪ medicines that can cause an irregular heartbeat, as Oxytocin may increase this effect; ▪ anaesthetics which you breath in (e.g. to put you to sleep during surgery), such as halothane, cyclopropane, sevoflurane or desflurane), as these may weaken your contractions, or cause problems with your heartbeat; ▪ anaesthetic medicines for local or regional pain relief, in particular an epidural for pain relief during labour. Oxytocin may increase the blood vessel narrowing effect of these medicines and cause an increase in blood pressure. Please tell your doctor or midwife if you are taking or have recently taken any other medicines including medicines obtained without a prescription. Oxytocin with food and drink You may be told to keep the amount of fluids you drink to a minimum. Pregnancy, breastfeeding and fertility Based on the wide experience of use and the nature of this medicine, it is not expected that Oxytocin would be a risk to your baby when used correctly. Oxytocin may be found in small amounts in breast milk but is not expected to have harmful effects because it is quickly inactivated by your baby's digestive system. Driving and using machines Oxytocin can start labour. Women with uterine contractions should not drive or use machines. Oxytocin contains sodium This medicinal product contains less than 1 mmol sodium (23 mg) per 1 ml ampoule, i.e. essentially 'sodium-free'.
May 2024
3.
How to take it
to you
Oxytocin should only be given under medical supervision and in a hospital. Your doctor or midwife will decide when and how to treat you with Oxytocin. If you think that the effect of Oxytocin is too strong or too weak, tell your doctor or midwife. While you are receiving Oxytocin, both you and your baby will be closely monitored. Oxytocin is usually diluted before use and given as an intravenous infusion (drip) into one of your veins. The usual dose is different in the following circumstances: To start or help contractions during labour: The rate of infusion will start at 2 to 8 drops per minute. This may be gradually increased to a maximum rate of 40 drops per minute. The infusion rate can often be reduced once the contractions reach an adequate level, about 3 to 4 contractions every 10 minutes. If your contractions do not reach the adequate level after 5 IU (8.3 micrograms), the attempt to start labour should be stopped and then repeated the following day. Miscarriage: The dose is 5 IU (8.3 micrograms) by infusion into a vein. In some cases this may be followed by a drip at 40 to 80 drops per minute. Caesarean section: The dose is 5 IU (8.3 micrograms) by infusion into a vein immediately after delivery of your baby. Prevention of bleeding after delivery: The dose is 5 IU (8.3 micrograms) by infusion into a vein after delivery of the placenta. Treatment of bleeding after delivery: The dose is 5 IU (8.3 micrograms) by infusion into a vein. In some cases this may be followed by a drip containing 5 to 20 IU (8.3 to 33.4 micrograms) of oxytocin. Older people (65 years and over): Oxytocin is not intended for use in elderly. Children and adolescents: There is no information on use in children (2-11 years) or adolescents (12-17 years). Oxytocin is not intended for use in children or adolescents. Patients with kidney disease: There is no information on use in patients with kidney disease. However, you should tell your doctor if you suffer from kidney problems (see section 2). Patients with liver disease: There is no information on use in patients with liver disease.
May 2024
If you receive more Oxytocin than you should As this medicine is given to you in hospital, it is very unlikely that you will receive an overdose. If anyone accidentally receives this medicine, tell the hospital accident and emergency department or a doctor immediately. Show any left over medicines or the empty packet to the doctor. An overdose of Oxytocin could cause: ▪ very strong contractions of your womb; ▪ damage to your womb which could include tearing; ▪ the placenta to come away from your womb; ▪ amniotic fluid (the fluid around the baby) to enter your bloodstream; ▪ harm to your baby. If you miss a dose of Oxytocin As a doctor or midwife is giving you this medicine, you are unlikely to miss a dose. If you have any further questions on the use of this medicine, ask your doctor or midwife. 4.
Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them. Your doctor may consider it necessary to treat the side effects of Oxytocin with other medicines. Some side effects could be serious. If any of the following occur, tell your doctor straight away: The following side effect may affect between 1 and 10 in every 10,000 patients: • a severe allergic (anaphylactic/anaphylactoid) reaction with difficulty in breathing, dizziness and lightheadedness, feeling faint, nausea, cold and clammy skin or a fast or weak pulse • Swelling of the face, lips, tongue, throat, and/or extremities (possible signs of angioedema) The following side effects have been reported in Oxytocin. Common side effects (affects more than 1 in 100 patients) ▪ Headache ▪ Fast or slow heartbeat ▪ Feeling or being sick. Uncommon side effects (affects more than 1 in 1,000 patients) ▪ An irregular heartbeat. Rare side effects (affects more than 1 in 10,000 patients) ▪ Skin rashes.
May 2024
Other side effects Effects in the mother: Not known (cannot be estimated from the available data) ▪ Chest pain (angina) ▪ Irregular heartbeat (QTc prolongation seen on electrocardiogram) ▪ Haemorrhage (bleeding) ▪ Excessive or continuous contractions ▪ Tearing of the womb ▪ Fluid retention (water intoxication). Symptoms may include headache, anorexia (loss of appetite), feeling or being sick, stomach pain, sluggishness, drowsiness, unconsciousness, low levels of certain chemicals in the blood (e.g. sodium or potassium), fits ▪ Low blood salt levels ▪ Sudden fluid overload in the lungs ▪ Sudden brief sensation of heat often over the whole body ▪ Abnormal blood clotting, bleeding and anaemia (disseminated intravascular coagulation) ▪ spasm of the muscles of the womb. Effects in the baby: Not known (cannot be estimated from the available data) Excessive contractions may cause: ▪ Shortage of oxygen, suffocation and death ▪ Low blood salt levels. Reporting of side effects If you get any side effects, talk to your doctor or midwife. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via: Yellow Card Scheme Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine. 5.
How to store it
Oxytocin
Keep this medicine out of the sight and reach of children. Store in a refrigerator (2 °C – 8 °C). May be stored up to 30°C for 3 months but must then be discarded. Keep the ampoules in the outer carton in order to protect from light. Do not use this medicine after the expiry date which is stated on the carton. The expiry date refers to the last day of that month. Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
May 2024
6.
Contents of the pack and other information
What Oxytocin contains The active substance is oxytocin. Each ml of solution contains 10 IU (16.7 micrograms) oxytocin. The other ingredients are: acetic acid, glacial; sodium acetate trihydrate; sodium chloride; sodium hydroxide; water for injections. What Oxytocin looks like and contents of the pack Colourless, clear liquid with characteristic odour. Transparent 1 ml type 1 glass ampoules. Pack sizes: 5 ampoules 10 ampoules Not all pack sizes may be marketed. Marketing Authorisation Holder Esteve Pharmaceuticals Ltd, The Courtyard Barns, Choke Lane, Cookham Dean, Maidenhead, Berks, SL6 6PT, United Kingdom Manufacturer AS GRINDEKS. Krustpils iela 53, Rīga, LV-1057, Latvia For any information about this medicine, please contact the Marketing Authorisation Holder. This leaflet was last revised in 05/2024. ————————————————————————————————————
May 2024
The following information is intended for healthcare professionals only: Oxytocin 10 IU/ml Solution for infusion Indication
Method of administration
Induction or enhancement of labour
Oxytocin should not be started for 6 hours following administration of vaginal prostaglandins. Oxytocin 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 (8.3 micrograms) of Oxytocin be added to 500 ml 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. 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 2 to 8 drops/minute (1 to 4 milliunits/minute). It may be gradually increased at intervals not shorter than 20 minutes and increments of not more than 1 to 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 20 drops/minute (10 milliunits/minute), and the recommended maximum rate is 40 drops/minute (20 milliunits/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
May 2024
Indication
Method of administration
pregnancy, when the uterus is less sensitive to oxytocin, it is advisable to use a more concentrated oxytocin solution, e.g., 10 IU (16.7 micrograms) in 500 ml. 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 (8.3 micrograms), 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 2 to 8 drops/minute (1 to 4 milliunits/minute). 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. Incomplete, inevitable or 5 IU (8.3 micrograms) by i.v. infusion (5 IU diluted in missed abortion 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 (8.3 micrograms) 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 (8.3 micrograms) 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 variablespeed infusion pump over 5 minutes) after delivery of the placenta.
May 2024
Indication
Method of administration
Treatment of postpartum 5 IU (8.3 micrograms) by i.v. infusion (5 IU diluted in uterine haemorrhage 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 (8.3 to 33.4 micrograms) of oxytocin in 500 ml of an electrolyte-containing diluent, run at the rate necessary to control uterine atony.
Incompatibilities: Oxytocin should not be infused via the same apparatus as blood or plasma, because the peptide linkages are rapidly inactivated by oxytocin-inactivating enzymes. Oxytocin is incompatible with solutions containing sodium metabisulphite as a stabiliser. Instructions on preparation and dilution: Oxytocin is compatible with the following infusion fluids: sodium chloride 0.9 %, dextrose 5 %, Ringer's solution, acetated Ringer's solution. For drip infusion it is recommended that 5 IU (8.3 micrograms) of Oxytocin be added to 500 ml 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. To ensure even mixing, the bottle or bag must be turned upside down several times before use. Storage of diluted product: see 'Shelf life' below. Shelf life: 4 years. Chemical and physical in-use stability has been demonstrated for 48 hours at 25 °C when diluted with the solutions stated in subsection 'Instructions on preparation and dilution' above. From a microbiological point of view, the product should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 2 to 8 °C, unless dilution has taken place in controlled and validated aseptic conditions.
May 2024
Frequently asked questions about Oxytocin 10 IU/ml Solution for infusion
How do I take Oxytocin 10 IU/ml Solution for infusion?
Oxytocin 10 IU/ml Solution for infusion comes as infusion containing 10iu/ml. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
What is the active substance in Oxytocin 10 IU/ml Solution for infusion?
The active substance in Oxytocin 10 IU/ml Solution for infusion is oxytocin.
Are there equivalent medicines to Oxytocin 10 IU/ml Solution for infusion?
Medicines with the same active substance, strength and form include: Oxytocin 10 IU/ml Concentrate for Solution for Infusion, Oxytocin 10 IU/ml Concentrate for Solution for Infusion, Oxytocin 10 IU/ml Concentrate for Solution for Infusion. They are interchangeable only if your prescriber or pharmacist says so.
Where does this information come from?
This leaflet reproduces the patient information leaflet approved for Oxytocin 10 IU/ml Solution for infusion, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Can I get Oxytocin 10 IU/ml Solution for infusion without a prescription?
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
About this leaflet
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
- Source: electronic medicines compendium (emc), Datapharm
- Active substance: oxytocin
- Official document: view the original leaflet on emc →
⚕For healthcare professionals — Summary of Product Characteristics (SmPC)Full SmPC: dosage, interactions, contraindications, warnings+
4.1. Therapeutic indications
Antepartum
– Induction of labour for medical reasons, e.g. in cases of post-term gestation, premature rupture of membranes, pregnancy-induced hypertension (pre-eclampsia).
– 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, following delivery of the child.
– Prevention and treatment of postpartum uterine atony and haemorrhage.
4.2. Posology and method of administration
Posology
Induction or enhancement of labour: Oxytocin should not be started for 6 hours following administration of vaginal prostaglandins.
Oxytocin 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 (8.3 micrograms) of Oxytocin be added to 500 ml 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). 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 2 to 8 drops/minute (1 to 4 milliunits/minute). It may be gradually increased at intervals not shorter than 20 minutes and increments of not more than 1 to 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 20 drops/minute (10 milliunits/minute), and the recommended maximum rate is 40 drops/minute (20 milliunits/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, e.g., 10 IU (16.7 micrograms) in 500 ml. 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 (8.3 micrograms), 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 2 to 8 drops/minute (1 to 4 milliunits/minute) (see section 4.3).
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.
Incomplete, inevitable, or missed abortion: 5 IU (8.3 micrograms) 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 (8.3 micrograms) 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 (8.3 micrograms) 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.
Treatment of postpartum uterine haemorrhage: 5 IU (8.3 micrograms) 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 (8.3 to 33.4 micrograms) of oxytocin in 500 ml of an electrolyte-containing diluent, run at the rate necessary to control uterine atony.
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
There are no indications for use of Oxytocin in children or adolescents.
Older people (65 years and over)
There are no indications for use of Oxytocin in elderly.
Method of administration Intravenous infusion.
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 contraindicated: 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.
Oxytocin should not be used for prolonged periods in patients with oxytocin-resistant uterine inertia, severe pre-eclamptic toxaemia or severe cardiovascular disorders.
Oxytocin must not be administered within 6 hours after vaginal prostaglandins have been given (see section 4.5).
4.4. Special warnings and precautions for use
Oxytocin 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
Oxytocin 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
Oxytocin 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).
When Oxytocin 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 Pregnancy induced 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 postpartum 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).
Anaphylaxis in women with latex allergy
There have been reports of anaphylaxis following administration of oxytocin in women with a known latex allergy. Due to the existing structural homology between oxytocin and latex, latex allergy/intolerance may be an important predisposing risk factor for anaphylaxis following oxytocin administration.
4.5. Interaction with other medicinal products and other forms of interaction
Interactions resulting in a concomitant use not recommended
Prostaglandins and their analogues
Prostaglandins and their analogues facilitate contraction of the myometrium hence oxytocin can potentiate the uterine action of prostaglandins and analogues and vice versa (see section 4.3).
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).
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
Pregnancy
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.
One study has shown that treatment of rats with oxytocin in early pregnancy at doses considered sufficiently in excess of the maximum recommended human dose caused embryonic loss. No standard reproductive performance studies with oxytocin are available
Breastfeeding
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.
Fertility
Animal reproduction studies have not been conducted with oxytocin. The effects of oxytocin on fertility are unknown.
4.7. Effects on ability to drive and use machines
Oxytocin 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). 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).
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).
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).
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 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000), including isolated reports; not known (cannot be estimated from the available data). The adverse reactions (ADRs) tabulated below are based on clinical trial results as well as post-marketing reports.
The adverse drug reactions derived from post-marketing experience with oxytocin 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
Adverse drug reaction
Immune system disorders
Rare: Anaphylactoid reaction associated with dyspnoea, hypotension or shock
Nervous system disorders
Common: Headache
Cardiac disorders
Common: Tachycardia, bradycardia
Uncommon: Arrhythmia
Not known: Myocardial ischaemia,
Electrocardiogram QTc prolongation
Vascular disorders
Not known: Hypotension, haemorrhage
Gastrointestinal disorders
Common: Nausea, vomiting
Skin and subcutaneous tissue disorders
Rare: Rash
Not Known: Angioedema
Pregnancy, puerperium and perinatal conditions
Not known: Uterine hypertonicity, tetanic contractions, rupture of the uterus
Metabolism and nutrition disorders
Not known: Water intoxication, maternal hyponatraemia
Respiratory, thoracic and mediastinal disorders
Not known: Acute pulmonary oedema
General disorders and administration site conditions
Not known: Flushing
Blood and lymphatic system disorders
Not known: Disseminated intravascular coagulation
Table 2 Adverse drug reactions in foetus/neonate
System organ class
Adverse drug reaction
Pregnancy, puerperium and perinatal conditions
Not known: Foetal distress, asphyxia and death
Metabolism and nutrition disorders
Not known: Neonatal hyponatraemia
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. lt allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via Yellow Card Scheme (www.mhra.gov.uk/yellowcard) or search for MHRA Yellow Card in the Google Play or Apple App Store.
4.9. Overdose
The fatal dose of oxytocin has not been established. Oxytocin 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 section 4.8. 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 oxytocin, 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, by judicious use of diazepam. In the case of coma, a free airway should be maintained with routine measures normally employed in the nursing of the unconscious patient.
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