Oxytocin

General characteristics. Structure:

Active agent: oxytocin synthetic – 5 ME Excipients: chlorobutanol гемигидрат (хлорбутанолгидрат), acetic acid, water for injections – to 1 ml.

Pharmacological properties:

Hormonal means, polypeptide analog of hormone of a back share of a hypophysis. Possesses the uterotoniziruyushchy, stimulating patrimonial activity and lactotropic action. Has a promoting effect on smooth muscles of a uterus, increases sokratitelny activity of a myometrium and to a lesser extent a tone (especially at the end of pregnancy, during patrimonial activity and directly during delivery). Under the influence of oxytocin permeability of cellular membranes for Ca2+ calcium ions increases, rest potential decreases and their excitability increases (reduction of membrane potential leads to increase in frequency, intensity and duration of reductions). In small doses oxytocin increases the frequency and amplitude of reductions of a uterus, in high doses or at repeated introduction promotes increase in a tone of a uterus, increase and strengthening of its reductions (up to tetanic). Stimulates secretion of breast milk, strengthening production of prolactin a front share of a hypophysis. Reduces myoepithelial cells around alveoluses of a mammary gland, stimulates intake of milk to large canals or sine, promoting strengthening of department of milk. It is almost deprived of vasopressor and antidiuretic action (shows them only in high doses), does not cause reduction of muscles of a bladder and intestines. At intramuscular and hypodermic administration of drug the effect occurs in 1-2 min. and 20-30 min. last; at intravenous administration the effect occurs in 0,5-1 min.; at intranasal introduction - the effect occurs within several minutes. 

Pharmacokinetics. An elimination half-life - 1 - 6 min. (decreases on late durations of gestation and in the period of a lactation). Communication with proteins of plasma - low (30%). It is well soaked up through a mucous membrane of a nose. It is metabolized in a liver and kidneys. During pregnancy in plasma, target organs, a placenta concentration of the oxytocinase inactivating endogenous and exogenous oxytocin increases. Removal generally kidneys in not changed look.

Indications to use:

For excitement and stimulation of patrimonial activity (primary and secondary weakness of patrimonial activity, need of early delivery in connection with a gestosis, a Rhesus factor conflict, pre-natal death of a fruit; postmature pregnancy, a premature bursting of waters, conducting childbirth in pelvic presentation).
For prevention and treatment of hypotonic uterine bleedings after abortion (including at big durations of gestation), in an early puerperal period and for acceleration of puerperal involution of a uterus; for strengthening of sokratitelny ability of a uterus at Cesarean section (after removal of an afterbirth).
Hypolactation in a puerperal period.
The painful premenstrual syndrome which is followed by hypostases, increase in body weight.

Route of administration and doses:

Intravenously (struyno slowly and kapelno), intramusculary, subcutaneously, in a wall or a vulval part of a neck of uterus, intranazalno (by means of a pipette). The single dose for introduction in oil depending on a clinical situation usually varies from 2 to 10 ME (from 0,4 to 2 ml); for in/in introductions (struyno slowly or kapelno) the single dose usually makes 5-10 ME (1-2 ml).
For initiation of childbirth - in oil, on 0,5-2 ME (0,1-0,4 ml of drug); if necessary repeat injections each 30-60 min.
Induction of childbirth: in/in kapelno, 10 ME oxytocins (2 ml of drug) on 1 l of 5% of solution of a dextrose (glucose), at development of excessive reductions of a uterus infusion delay quickly leads to decrease of the activity of a myometrium. Introduction there begin from 5-8 caps/min., with the subsequent increase in speed depending on the nature of patrimonial activity, but no more than 40 caps/min. During infusion constant control of uterine activity and number of cordial reductions of a fruit is necessary.
Abortion in the course: in/in kapelno, 10 ME (2 ml) oxytocin on 500 ml of 5% of solution of a dextrose (glucose) with a speed of 20-40 of cap/min.
For prevention of hypotonic uterine bleedings oxytocin is entered in oil, on 3-5 ME (0,6-1 ml) by 2-3 times a day daily within 2-3 days, introduction in oil 10 ME (2 ml) right after department of a placenta is admissible. For treatment of hypotonic uterine bleedings enter 5-8 ME (1-1,6 ml) 2-3 times a day during 3 days. If necessary enter in/in kapelno on 10-40 ME (2-8 ml) oxytocin dissolved on 100 ml of donor blood.
Strengthening of department of milk (for prevention of mastitis because of stagnation of milk): in oil - 2 ME (0,4 ml).
For stimulation of a lactation in a puerperal period - in oil or intranazalno, 0,5 ME (0,1 ml) in 5 min. prior to feeding.
At childbirth in pelvic presentation - 2-5 ME (0,4-1 ml).
At operation of Cesarean section (after removal of an afterbirth) oxytocin is entered into a uterus wall in a dose 3-5 ME (0,6-1 ml).

Features of use:

To apply only under observation of the doctor in the conditions of a hospital under control of sokratitelny activity of a uterus, a condition of a fruit, the arterial pressure (AP) and the general condition of the woman.

Side effects:

Bradycardia (at mother and a fruit), a lowering of arterial pressure, shock or increase in arterial pressure and subarachnoidal bleeding, disturbances of a heart rhythm (including at a fruit); bronchospasm; nausea, vomiting, water delay; neonatal jaundice, decrease in concentration of fibrinogen at a fruit, allergic reactions.

Interaction with other medicines:

Oxytocin strengthens pressor effect of sympathomimetic amines.
In combination with monoamine oxidase inhibitors the risk of increase in arterial pressure increases.
The halothane and cyclopropane increase risk of development of arterial hypotension.

Contraindications:

Hypersensitivity; a narrow basin (anatomic and clinical), the cross and slanting provision of a fruit, front presentation, premature births, the menacing hysterorrhesis, hems on a uterus (after the postponed earlier Cesarean section, uterus operation), uterus hyperdystension, a uterus after repeated childbirth, partial placental presentation, uterine sepsis, an invasive carcinoma of a neck of uterus; the uterus hyper tone (which arose not during childbirth), a fruit prelum, arterial hypertension, a chronic renal failure. 
Use at pregnancy is not specified.

Overdose:

Symptoms: fruit prelum, fruit asphyxia, fruit bradycardia, puerperal bleeding, uterus tetanus, hysterorrhesis, uteroplacental hypoperfusion, hypoxia, hypercapnia, death of a fruit, birth trauma of a fruit, water intoxication, spasms.
Treatment: drug withdrawal, reduction of administration of liquid, an artificial diuresis, hypertonic salt solution of sodium of chloride, normalization of electrolytic balance, barbiturates (with care), careful observation.

Storage conditions:

List B. In the place protected from light, at a temperature from 8 to 20 °C. To store in the places unavailable to children. 
Period of validity 2 years. Not to use upon termination of a period of validity.

Issue conditions:

According to the recipe

Packaging:

1 ml of solution for injections contains oxytocin 5 ME; in ampoules on 1 ml, in the blister of 5 pieces, in a cardboard pack 2 blisters.