Medication Description: Oxytocin (Oxytocinum)
Oxytocin is a peptide hormone (octapeptide) of the posterior pituitary gland. It consists of a pentapeptide cycle and a side chain of residues of three amino acids. The cycle is formed in such a way that two groups of cysteine (in positions 1 and 6), being closed, create a disulfide bridge.
Currently, oxytocin is produced synthetically.
Synonyms: Shintocinon, Ipofamin, Ocytocin, Orasthin, Oxystin, Oxytocin, Partocon, Pitocin, Pitupartin, Synpitan, Syntocinon, Utedrin, Uteracon, etc.
The main pharmacological property of oxytocin is the ability to cause strong contractions of the muscles of the uterus, especially pregnant women. This action is associated with the effect of oxytocin on the cell membrane of the myometrium; It has no direct effect on the contractile elements of myoplasma. Under the influence of oxytocin, the permeability of the membrane for potassium ions increases, its potential decreases and its excitability increases. Oxytocin also increases the secretion of milk, enhancing the production of lactogenic hormone of the anterior pituitary (prolactin). In addition, it can cause a rapid release (ejection) of milk from the mammary gland due to the impact on its contractible elements. The effect on the uterus of synthetic oxytocin is similar to the natural preparations of the posterior lobe of the pituitary (pituitrin, gyfototsinom).
Due to the fact that oxytocin is free from other hormones, it has a more selective effect, gives only a weak antidiuretic effect; does not significantly affect blood pressure or increases it somewhat. Since the drug is free from proteins, peptides and other by-products, it can be administered intravenously without the risk of anaphylactic and pyrogenic action.
Used to induce and stimulate labor. The drug is most effective in case of premature discharge of amniotic fluid. It is also prescribed for weakness of labor associated with atony of the uterus, and hypotonic uterine bleeding. It can be used for artificial induction of labor (with complications of pregnancy).
Enter intravenously or intramuscularly. Intravenous administration causes rapid (after 1/2 - 1 min) intensification of contractions; sluggish contractions become stronger, and in the absence of contractions they usually quickly appear. Intramuscular administration has a less dramatic effect.
For the initiation of labor, intramuscular injection of 0.5 - 2, 0 U (= 0.5 - 2, 0 IU) of oxytocin is injected: if necessary, repeat injections every 30 - 60 minutes.
For intravenous administration, dilute 1 ml of synthetic oxytocin (5 U) in 500 ml of 5% glucose solution and pour in drip from 5 to 8 drops per minute, then the number of drops is gradually increased (every 5 to 10 minutes by 5 drops, but not more than 40 drops per minute) to establish vigorous labor. Drip administration is continued throughout the entire birth act, and the amount of the solution injected can be reduced to the minimum that supports good labor activity.