Oxytocin Injection (NeOxyn) is a hormone that causes increased uterine contractility. It is used during labor induction, abortion, and to control postpartum bleeding.

Oxytocin Injection (NeOxyn) Uses:

• Antepartum:

  • Used for induction of labor in patients with a medical indication (eg, Rh problems, maternal diabetes, preeclampsia, at or near term).
  • Stimulation or reinforcement of labor (as in selected cases of uterine inertia).
  • Adjunctive therapy in the management of incomplete or inevitable abortion

• Postpartum:

  • To produce uterine contractions during the third stage of labor.
  • To control postpartum bleeding or hemorrhage.

Oxytocin Injection (NeOxyn) Dose in Adults

Note: Dose depends on the uterine response and must be individualized and started at a very low level for every patient.

Oxytocin Injection Induction or stimulation of labor:

IV:

• • An infusion pump is required to administer IV oxytocin.
  • The ideal dosing regimen has not been determined and Multiple protocols are available.
  • Discontinue at once in case of uterine hyperactivity and/or fetal distress.
  • If uterine contractions become too powerful, the infusion can be stopped abruptly.

• Initial: 0.5 to 1 milliunits/minute.
• Slowly increase the dose in increments of 1 to 2 milliunits/minute every 30 to 60 minutes until the desired contraction pattern is achieved;
• The dose may be reduced by similar increments after achieving the desired frequency of contractions and labor has reached 5 to 6 cm cervical dilation.
• Because of decreased uterine sensitivity before term, higher infusion rates may be needed.
• Infusion rates up to 6 milliunits/minute provide oxytocin levels similar to those with spontaneous labor; rates >9 to 10 milliunits/minute are rarely required.
• Low-dose regimen (off-label dose):
  • Initial 0.5 to 2 milliunits/minute, Slowly increase by 1 to 2 milliunits/minute every 15 to 40 minutes.
• High-dose regimen (off-label dose):
  • Initial 6 milliunits/minute, Slowly increase by 3 to 6 milliunits/minute every 15 to 40 minutes.
  • In the case of hyper-stimulation decrease to 3 milliunits/minute.
  • For recurrent hyper-stimulation bring down an incremental increase to 1 milliunit/minute.

Oxytocin Injection Dose in the Postpartum uterine bleeding:

Note:

• Oxytocin is used for both prevention and treatment of postpartum bleeding associated with uterine atony and vaginal or surgical delivery.
• In women undergoing a nonelective cesarean delivery if oxytocin was previously administered during labor oxytocin receptors become desensitized and decrease in number in the myometrium, Hence larger doses may be needed.
• May be administered by slow IV bolus, IV infusion, or IM injection.
• Rapid IV bolus administration can lead to cardiovascular collapse.
• rapid IV boluses are not recommended for women with cardiovascular risk factors.
• In women not requiring treatment by IV infusion, administration via slow IV bolus may be preferred over IM injection based on a study evaluating oxytocin use following vaginal delivery.
• IM:
  • 10 units after delivery of the placenta

• IV:
  • Note:
    • The optimal regimen has not been established.
  • 5 units or 10 units may be given initially followed by a maintenance infusion of 10 units/hour.
  • Maximum total dose: 40 units.
  • The dose may be administered using a standardized infusion containing 30 units in 500 mL NS or LR or by adding 10 to 40 units to a running infusion solution depending on the amount of infusion fluid remaining (maximum: 40 units in 1,000 mL of IV fluid);
  • adjust infusion rate to maintain uterine contraction and control uterine atony.
  • Lower bolus doses (0.5 to 3 units) for the prevention of postpartum hemorrhage have also been evaluated in women undergoing elective cesarean delivery.

Oxytocin Injection dose as an adjunctive treatment for abortion: IV:

• Incomplete, inevitable, or elective abortion:

  • 10 units as an IV infusion after suction or a sharp curettage (used to help contract the uterus)

• Mid-trimester elective abortion:

  • 10 to 20 milliunits/minute;
  • The maximum total dose: 30 units/12 hours (may reduce injection to abortion time)

Use in Children:

Not indicated.

Oxytocin Injection Pregnancy Risk Category: X

• [US Boxed Warning] : For medical induction of labor, not for elective.
• Exogenous oxytocin is expected to reach the fetal circulation in small amounts.
• Teratogenic effects are not expected when used as directed.
• Side effects that are not teratogenic have been reported in both the mother and the neonate.

Use of oxytocin while breastfeeding

• Exogenous oxytocin mediates the ejection of milk. Exogenous oxytocin administration may slow down the process of starting breastfeeding.
• Mother and baby can have skin-to-skin contact which helps release endogenous oxytocin as well as the formation of the milk ejection reaction.

Dose in Kidney Disease

No dosage adjustments provided in the manufacturer's labeling.

Dose in Liver Disease:

No dosage adjustments provided in the manufacturer's labeling.

Side effects of Oxytocin Injection:

• Cardiovascular:

  • Cardiac arrhythmia,
  • Hypertensive crisis,
  • Hypotension
  • Subarachnoid hemorrhage, tachycardia
  • Ventricular premature contractions

• Endocrine & metabolic:

  • Water intoxication (severe water intoxication with seizure and coma is associated with a slow oxytocin infusion over 24 hours)

• Gastrointestinal:

  • Nausea
  • Vomiting

• Genitourinary:

  • Postpartum hemorrhage
  • Uterine rupture

• Hematologic & oncologic:

  • Pelvic hematoma

• Hypersensitivity:

  • Anaphylaxis

Contraindications to Oxytocin Injection:

• Hypersensitivity to oxytocin and any component of the formulation
• Unfavorable fetal positions or presentations, such as transverse lies, are marked cephalopelvic disproportions.
• When delivery is not imminent, fetal distress.
• Hyperactive or hypertonic uterus.
• Contraindicated vaginal deliveries (invasive cervical cancer and active genital herpes), prolapse of cord, cord presentation or total placenta Previa are all reasons to avoid vaginal delivery.
• Operative intervention is preferred in obstetric emergencies.
• Insufficient uterine activity may result in insufficient progress.

Canadian labeling:Additional contraindications not listed in the US labeling:

• Severe toxemia;
• Prematurity or unripe Cervix
• Predisposition to uterine rupture (eg, grand multifidy, overdistention, caesarian delivery prior, other surgery involving uterus).
• Long-term uterine inertia from prolonged use
• Factors that predispose to amniotic fluid embolism or thromboplastin (eg, prolonged retention, placental abruption, and/or prolonged retention of the dead foetus)
• Any condition that causes fetal distress, including serious medical or obstetric issues;
• The inability of the doctor to be present

Warnings and precautions

• Antidiuretic effect

  • May cause an intrinsic antidiuretic reaction (i.e. water intoxication).
  • Water intoxication can lead to severe symptoms, including coma and death.
  • This is especially true if high doses are administered (40-50 milliits/minute), or if fluids are given by mouth.

• Cardiovascular effects

  • Following administration, there have been reports of hypotension, arrhythmias and myocardial injury, as well as peripheral vasodilation and tachycardia.
  • The dose and route of administration can affect the risk of adverse events. This is especially true for women suffering from cardiovascular disease.
  • Patients who are hemodynamically unstable should be treated with extreme caution.

• Maternal deaths:

  • When oxytocic medication was used to induce labor or augment the first or second stages, oxytocic drugs have been responsible for maternal deaths, including subarachnoid hemorhage or rupture of the uterus.

• Uterine effects:

  • Hypersensitivity or high doses of oxytocin can cause hypertonicity, spasms, tetanic contractions, or rupture in the uterus.

Oxytocin: Drug Interaction

Monitoring Parameters:

• Fluid intake and output.
• uterine activity(tone, amplitude, and frequency of contractions).
• maternalblood pressure.
• fetal heart rate in relation to uterine contractions.

How to administer Oxytocin Injection?

Induction or stimulation of labor:

• Administer as an IV infusion (drip method) via an infusion pump as the exact rate of infusion flow is mandatory.

Incomplete or inevitable abortion:

• Administer by IV infusion

Postpartum uterine bleeding:

• IV route preferred. Use IM if IV access is not available.
• IV push is not recommended; rapid IV bolus can lead to cardiovascular collapse.
• Slow IV injections (5 or 10 units over 1 minute) are preferred for women without cardiovascular risk factors.
• For women with cardiovascular risk factors give very slow injections (≥5 minutes).

Mechanism of action of Oxytocin Injection:

• The stimulation of uterine contraction is achieved by Oxytocin activating G protein-coupled receptors, which leads to an increase intracellular calcium levels within the uterine myofibrils.
• Further stimulating contraction, it also increases local prostaglandin formation.

The onset of action:

• Uterine contractions:
  • IM: 3 to 5 minutes;
  • IV: ~1 minute

Duration:

• IM: 2 to 3 hours;
• IV: 1 hour

Half-life elimination:

• 1 to 6 minutes;
• lesser in late pregnancy and during lactation

Excretion: Urine (small amount unchanged)

International Brand Names of Oxytocin Injection:

• Pitocin
• Ao Sai Juo Xing
• Cetocin
• Evatocin
• Lavoxin
• Litocin
• NeOxyn
• Ocin
• Octocin
• Ofost
• Oksitocins
• Oxitol
• Oxitone
• Oxitopisa
• Oxocin
• Oxycinon
• Oxyla
• Partocon INJ
• Pitocin
• Pitocin INJ
• Pitogin
• Piton S INJ
• Popicin
• Protocin
• Santocyn
• Solvoxine
• Synthetic Oxytocin INJ
• Syntocinon
• Syntocinon INJ
• Syntocinon Spray
• Tiacinon
• Udoxan
• Vitocin
• Xitocin
• Xytocin

Oxytocin Injection Brand Names in Pakistan: