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Brand

Veterinary:  Oxytocin

Human: Pitocin, Syntocinon

Availability

Veterinary:  20 USP Units/mL in 10mL, 30mL, and 100mL vials

Human: 10 Units/mL in 1 & 10mL vials, Syntocinon Nasal Spray 40 Units/mL

Pharmacology

Oxytocin is a synthetic compound. It is identical to the natural hormone which is found in the posterior pituitary. It causes potent and selective stimulation of uterine and mammary gland smooth muscle.

The name oxytocin means, “rapid birth”, because of the ability it has to contract the pregnant uterus (Bergersen, Pharmacology in nursing, fourteenth edition, page 603).

Oxytocin stimulates the contraction of the uterus by increasing sodium permeability of uterine myofibrils. It also has the ability to cause contraction of the myoepithelial cells which surround mammary alveoli and facilitate milk ejection.

Even though oxytocin has only weak antidiuretic properties, water intoxication can omlur if it is administered at a rapid rate, and/or if excessively large volumes of electrolyte-free intravenous fluids are administered.

Oxytocin is destroyed in the GI tract and must be given either IV, IM, SQ, or by nasal spay.

This drug is distributed in extracellular fluid, metabolized in the liver and kidneys and excreted unchanged in small amounts in the urine.

Indications

Used to induce or continue labor in normal presentation. Used to control bleeding following delivery.

Drug Interactions or Contraindications

Avoid using vasoconstrictors with oxytocin as it can result in hypertension.

Oxytocin considered contraindicated when dystocia present due to abnormal presentation without making correction.

Adverse Reactions

Relatively safe margins at reasonable dosage.

CNS:  subarachnoid hemorrhage, seizures

CV:  increases heart rate, blood pressure, systemic venous return, cardia output, and arrhythmias.

GU:  impaired uterine blood flow, pelvic hematoma, tetanic uterine contractions, uterine rupture, postpartum hemorrhage

Dosage Recommendations

0.2 units/kg to 3 units/kg , SQ  ¹

Considerations

• Store at refrigerated temperatures less than 25 degrees centigrade, and protect from freezing.
• Check solution to be sure it is clear and free of sediment.
• For reading:http://www.rmca.org/Articles/oxytocin.htm

Posted on June 23, 2003, 16:19, Last updated on December 14, 2008, 11:40 | Hormones