Download dosing schedule of oxytocin, ergometrene and prostglandins during

In clinical practice the following drugs are of
importance:
1- OXYTOCINE.
2- ERGOMETRINE.
3- PROSTAGLANDINS.
OXYTOCIN (PITOCIN,
SYNTOCINONE)
It is an octapeptide hormone released from
the posterior lobe of the pituitry gland.
It stimulate contraction of myometrium of
pregnant uterus particularly at term. It
also stimulate contraction of
myoepithelial cells of breast particularly
after sucking and cause release of
milk.
Clinical Uses:
1* Induction of labour.
2* Augmentation of slow labour.
3* prevention and treatment of post
partum
hemorrhage (combined with ergometrine).
4* Use as nasal spray to induce lactation.
5* Treatment of abortion.
CONTRAINDICATION
1- women of high parity(more than 5).
2- mechanical obstruction to safe normal vaginal
delivery such as contracted pelvis or abnormal fetus
presentation.
3- previous uterine scar such as caesarean section
and myomectomy.
is an obstetric complication in which the placenta is
inserted partially or wholly in lower uterine segment
4- (placenta previa).
ADMINSTRATION AND DOSAGE OF
OXYTOCIN
It is given by i.v. infusion, but it is also given as
nasal spray but this route show irregular
absorption which lead to less contractility.
Dose of oxytocin is measured in units
 500 USP (united states Pitocin) units = 1
mg
So each unit = 2 µg.
 - Usually oxytocin preparations
(syntocinon, Pitocin) contain 10 units/
ml.

for induction of labour or to augment slow
labour , the common method is to mix 2
units of oxytocin in 500 ml of 5%glucose
water solution and start running this at 1
ml
(15 drop)/min.
this gives approximate dose of 2-4 m unit
(milliunits) / min.

This dose is increased gradually at 15
min. interval according to strength and
frequency of uterine contraction. This
procedure can be done by manual
control or infusion pump.
Unwanted effects of oxytocin:
1-dose –related hypotension (arising from
its vasodilator action ).
 2-its antidiuretic hormone like action on
water excretion →water retention
&hyponatraemia.
 3-inappropriate use can lead to uterine
rupture .
 4-prolonged stimulation of uterus may
cause fetal arrhythmias.

ERGOMETRINE (Ergonovine):
It is one of ergot derivatives which act by
stimulation of
uterine activity. It differ from oxytocin by:
1- moderate dose of oxytocin cause generalized
Moderate dose of oxytocin cause contractions
of uterus particularly of the fundus segment
followed by full relaxation in between
.*contractions .

While moderate doses of ergometrine
cause contraction of uterus as a whole
i.e. Fundus &cervix (tend to compress
rather than to expel the fetus )with
faster contraction (tetanic contraction )
i.e. no relaxation in between .
2*Oxytocin is given parenterally only while
ergometrin is given parenteraly and orally
3* Duration of action of oxytocin is few seconds
while
ergometrine reach one hour.
4* ergometrine causes vasoconstriction leading to
increase blood pressure particularly in already
hypertensive patient, patient with peripheral
vascular disease and heart disease.
CLINICAL USES OF ERGOMETRINE
1 * Prophylaxis and treatment of post-partum
hemorrhage,
in normal labour and in
caesarean section.
2 * Treatment of bleeding in abortion.
3 * In puerperium if bleeding is heavy.
ADMINSTRATION AND DOSGE OF
ERGOMETINE
1* Orally : 0.5-1 mg, action begin after 8
min. and last for one hour.
2* i.m. : 100-500 µg, action begins within 2-6 min. .
3* i.v. : 250-500 µg, action begins within one min. .
In the treatment of postpartum hemorrhage , 500 µg
is given i.v. , if uterus is still flaccid with bleeding
give another same dose (but must be the last
dose). If bleeding continuous give oxytocin by i.v.
infusion which give quick action but brief.
For this reason oxytocin is usually mixed with
ergometrine in a preparation called syntometrine
which contains:
ergometrine 500 µg
oxytocin 5 i.u.
This preparation have the advantages of quik onset
of action (due to oxytocin) and prolonged effect
(due to ergometrine).
Side effects of Ergometrine:
 1- Vomiting
 2- Vasoconstriction ,vasospasm even of
the coronary arteries resuling in angina,
gangrene
 3- Hypertension

Character
Oxytocin
Ergometrine
Contraction
As
Tetanic
physiological
contraction
pattern
Uses
As mentioned
PPH.,mainly
Onset
Rapid onset
Moderate onset
Short duration
Long duration
&duration of
action
PROSTAGLANDINS
a) PGE2
b) PGF2ά
They are modified fatty acids results from enzymatic synthesis from
arachidonic acid. It has been suggested that it may play physiological
rule during labour:
1- Induction of labour when there are fetal or maternal contraindication
to oxytocin.
2- In case of fetal death in the uterus.
-When vaginal delivery is desired for safety of mother or child in cases
such as Rh. incompatibility or maternal diabetes mellitus.
They are modified fatty acids results from
enzymatic synthesis from arachidonic acid.
It has been suggested that it may play
physiological rule during labour:
 1- Induction of labour when there are fetal
or maternal contraindication to oxytocin.
 2- In case of fetal death in the uterus.
 3-When vaginal delivery is desired for
safety of mother or child in cases such as
Rh. incompatibility or maternal diabetes
mellitus.

ADMINISTRATION AND DOSAGE OF PGs
PGF2 available in 5 mg /ml sterile solution called
Dinaprest. They are given i.v. , extra –amniotically,
intra-amniotically, vaginal gel or vaginal pessary.
1-I.V. ROUTE.:
a5 mg / ml of PGF2α is used for induction of
labour when PG is not contra indicated as in
asthma . For I V drips, Add 1 ml from ampoule to
1000 ml or 0.5 ml to 500 ml of sterile normal
saline or 5 % glucose water, start with 2.5 µg /
minute, maintained at least 30 minutes, if good
contraction obtained, maintain the rate. If
contraction is weak increase the dose to 5 µg /

b- b- In therapeutic termination of
pregnancy, missed abortion or vesicular
mole. The dose is 50 µg / ml solution.
2- EXTRA-AMNIOTIC
 Take 1 ml of PGF2, add it to 19 ml
normal saline or 5% glucose water to
get 20 ml diluted solution containing 250
µg/ml. Insert Foley catheter (self
retaining) through cervix into space
between fetal membrane and uterine
wall. PGF2 solution is inserted through
the catheter with initial dose 1 ml then 3
ml every 2 hour.

3- INTRAAMNIOTIC
It is use for therapeutic termination of pregnancy in a
dose of 5 mg/ml solution used from ampule
without dilution.
Transabdominal tap of amniotic sac with drawn at
least one ml of amniotic fluid, then 40 mg (8 ml) of
PGF2 slowly injected in the amniotic sac.