OXYTOCIN, ERGOT ALKALOIDS & UTERINE RELAXARS Uterine stimulants (uterotonics) are medications given to cause a woman's uterus to contract, or to increase the frequency and intensity of the contractions. These drugs are used to induce (start) or augment (speed) labor; facilitate uterine contractions following a miscarriage; induce abortion; or reduce hemorrhage following childbirth or abortion. “Tocolytic Drugs” Relax the uterus and arrest threatened abortion or delay premature labor.

4. Genitourinary is a word that refers to the urinary and genital organs.
Urology is the branch of medicine concerned with the urinary tract in
both genders and the genital tract of the reproductive system in
males.
Nephrology is the branch of medicine concerned with the kidney.
What is the urinary tract?
The urinary tract includes the organ system primarily responsible for
cleaning and filtering excess fluid and waste material from the blood.
The urinary system is comprised of the following:
> kidneys
> ureters
> bladder
> urethra
The kidneys also function as glands that produce hormones
necessary for building red blood cells and regulating blood pressure.

5. Uterine stimulants
Uterine stimulants (uterotonics) are
medications given to cause a woman's
uterus to contract, or to increase the
frequency and intensity of the
contractions. These drugs are used to
induce (start) or augment (speed) labor;
facilitate uterine contractions following a
miscarriage; induce abortion; or reduce
hemorrhage following childbirth or
abortion.
Simply use to:
- to induce and/or augment labour
- to reduce postpartum bleeding
Examplesof uterine stimulants:
-oxytocin
-ergometrine (ergonovine)
- prostaglandins
Uterine
Relaxants
Also known as “Tocolytic Drugs”
Relax the uterus and arrest
threatened abortion or delay
premature labor.
Examplesof tocolytic drugs.
β2-adrenergic agonists (such as
ritodrine, salbutamol, or terbutaline)
oxytocin receptor antagonist (such
as atosiban)
Ca2+ channel blockers (such as
nifedipine or nicardipine)
Magnesium sulfate (MgSO4)
prostaglandin inhibitors (such as
Indomethacin)

8. >Oxytocin is a cyclic peptide hormone, secreted from posterior pituitary.
>It is synthesized in the cell bodies of para ventricular nucleus.
>It goes down the axons, and is stored within neurohypophysis.
>The precursor is rapidly converted by proteolysis to the active hormone
and secreted from nerve endings.
>Oxytocin is also synthesized in the luteal cells of the ovary, the
endometrium and the placenta.
>Stimuli include sensory stimuli from dilation of the cervix and vagina,
suckling.

9. •It is a nine amino acid peptide composed of 9 amino acid peptide,
containing a six amino acid disulfide ring and a three membrane
tail.

10. •Orally not highly active, degraded when given orally.
•Administered by I/V or IM route, at times intra nasal route may be
used (to stimulate milk ejection)
•Rapidly degraded by kidney and in liver.
•Plasma half life is 6 min.
•Not bound to plasma proteins.
•Destroyed by Oxytocinase (present in kidneys).
Dosage
•It is given I/V with fetal and maternal monitoring, so that fetal distress
does not take place.
•An infusion rate of 10mU/min is given and increased every 15-30 min.
•Nasal puff in each nostril is sprayed for lactation, one puff in each
nostril is used before nursing, mother is placed in sitting position, thus
milk ejection is enhanced.

11. •Oxytocin acts via G protein coupled receptors which activate Ca²+ -IP³
pathway and intracellular release of Ca²+ ions.
•Intracellular calcium release alters transmembrane ionic currents in
myometrial smooth muscle cells to produce sustained uterine contractions
(stimulate and enhance).
• Increased sensitivity of uterus to oxytocin, prostaglandins are also
synthesized leading to further augmentation of effects.
•As pregnancy advances, activity of uterus (uterine contractions) increase
and so does the sensitivity to oxytocin.
• Weak ADH like activity.
•Also affects myometrial smooth muscles and initiates contractions of
smooth muscles leading to milk ejection.
•Beta agonists, magnesium sulfate and inhalational anesthetics
antagonize the effects.

12. Uterus:
•Activity increases as reaches 3rd trimester, leading to
force and frequency of uterine contractions.
•Sensitivity is also enhanced and effects are mainly
related to fundus and body of uterus.
•Full relaxation may occur between contractions.
Breast
•Cause contraction of myoepithelial cells of mammary
alveoli surrounding collecting ducts, leading to milk
ejection from mammary alvoli, one puff is given in
each nostril.

13. CVS
•Due to direct effect, oxytocin causes vasodilation
and fall in blood pressure,
•Increased heart rate and tachycardia,
•Flushing might occur as well.
Kidney
•Weak ADH like activity
•May cause retention of fluids
•Decreased urine output, if given in high doses
•Pulmonary edema may occur

14. 1. Induction of Labor
Normal labor is allowed to progress, manipulation is not advisable, only
administered in certain conditions. (Rh incompatibility, DM, preeclampsia,
ecclampsia, toxemia of pregnancy, rupture of membranes)
Initially 0.5-2 units/min administered, dose may be increased within 15-30
minutes till effective uterine contractions are achieved with maternal and fetal
monitoring.
2. Augmentation of Labor
If labor is not progressing.
3. Third stage of Labor and puerperium
To decrease the post partal hemorrhage, usually administered at the time of
delivery of placenta to decrease the chances of post partum hemorrhage.
10-40 units oxytocin in 1 litre of 5% dextrose is infused slowly. Ergot alkaloids
(ergometrine) are also utilized for this purpose (o.2-0.3 mg are given). If
ergometrine is contraindicated, oxytocin may be used.
4. Milk ejection
Enhances milk ejection.

15. Maternal and fetal deaths due to:
• hypertensive episodes,
•uterine rupture,
•water intoxication if rapidly
•Afibrinogenemia is also reported

16. Prostaglandins are said to have similar
effects, act as uterine analogs.
• PGE2, PGF2α and 15 methyl PGF2α
are potent uterine stimulants.
• PG have been detected in maternal
blood.
• Also enhance uterine stimulant activity,
may augment the contractions.

17. • Erogot alkaloids obtained from
clavicepspurpura.
• They increase force, frequency and duration
of uterine contractions.
• Gravid uterus is more sensitive and involves
the lower segment as well.
• Partial agonist action on 5-HT2 and α
adrenergic receptors.
• Used to decrease post partum hemorrhage

18. I/V oxytocin is given in a dose of
0.5milli units/min, till three
contractions are achieved in 10
minutes. Purpose of doing the test is
to access fetal well being. We
compare maternal blood flow with
that of fetal heart rate. This is to try to
access placental circulatory reserve.

19. Character Oxytocin Ergometrine
Contractions Resembles normal
physiological
contractions
Tetanic contraction ; doesn't
resemble normal physiological
contractions
Uses *To induce &augment
labor.
*Post partum
hemorrhage
Only in P.partum hemorrhage
Onset &
Duration
Rapid onset
Shorter duration of
action
Moderate onset
Long duration of action

21. Also known as “Tocolytic Drugs”
Examples of tocolytic drugs.
1. β2-adrenergic agonists (such as ritodrine,
salbutamol, or terbutaline)
2. oxytocin receptor antagonist (such as atosiban)
3. Ca2+ channel blockers (such as nifedipine or
nicardipine)
4. Magnesium sulfate (MgSO4)
5. prostaglandin inhibitors (such as Indomethacin)

22. Action and Uses :
Relax the uterus and arrest threatened abortion or
delay premature labor.
Indications:
Agents given to decrease the contractions of uterus
to relax it, given in cases:
when there are chances of threatened abortion or
prematurity
if we want to shift mother to better health facilities
unit
in conditions where fetal lungs are not mature,
glucocorticoids are given to allow maturation.
Labor may be slowed down for days or even weeks.

24. •A β2 selective agonist.
•It has a major uterine relaxant action.
•Doses given as I/V infusion of 50 mcg/min, dose may be
increased after every 10 minutes till tone is decreased.
•Causes postponement of delivery in 70% cases.
Mechanism of action:
Bind to β-adrenoceptors , activate enzyme
Adenylatecyclase , increase in the level of cAMP reducing
intracellular calcium level and decreasing the sensitivity of
actin myosin contractile unit.

25. Side Effects;
•Hypertension,
•hyperinsulinemia ,
•hypokalemia,
•anxiety,
•arrhythmias,
•pulmonary edema,
•hyperglycemia,
•restlessness,
•headache
•Salbutamol and terbutaline may also be used.
Contraindications
•Diabetes
•Severe hypertension

26. •Not FDA approved for the treatment of premature labor—
historically used in rural areas.
•Oxytocin receptor antagonist (such as atosiban)
Mechanism of Action:
 Direct relaxant effect on the myometrium and inhibition of
oxytocin release
Indications/Therapeutic Effects:
 Inhibit premature labor
Pharmacokinetics:
 Loading dose (10% injection): 7.5 ml/kg/hr IV for two (2)
hours with a maintenance infusion rate of 1.5 ml/kg/hr IV for
up to 10 hours

27. •Ca+ influx causes uterine contractions while Ca channel blockers have
opposing effects.
•Nifedipine given orally every 20-30 min till uterine contractions subside.
Mechanism of action:
•Causes relaxation of myometrium
•Markedly inhibits the amplitude of spontaneous and oxytocin-induced
contractions
Unwanted effects:
• Headache, dizziness
• Hypotension
• Flushing
•Constipation
• Ankle edema
• Coughing
• Wheezing
• Tachycardia

28. Nifedipine (Procardia®)
Calcium channel blocker
 Not FDA approved for the treatment of premature labor.
Mechanism of Action:
 All smooth muscles (uterus) use Ca2+ influx through L-
type calcium channels for contraction.
Indications/Therapeutic Effects:
 Starting to be used as a 1st line drug, especially with b2
agonists now not available
Adverse Effects:
 Flushing, headache, dizziness, transient hypotension
Contraindications/Precautions:
 Concomitant use of calcium channel blocker

29. Previously used, now uses are declining
Used to control convulsions and to reduce BP
in toxemia of pregnancy.
Given by I/V infusion.
Side Effects;
•Cardiac arrhythmias,
•muscular paralysis,
•CNS and respiratory depression.

30. Mechanism of Action:
 mechanism unknown.
 Not FDA approved for the treatment of premature labor
 Used as a 1st line drug, depending on choice
Indications/Therapeutic Effects:
 May be given to pre-eclamptic patients to prevent convulsions or
as a treatment for eclamptic patients (FDA approved).
Pharmacokinetics:
 IV, slowly administered (significant hypotension or asystole if too
fast)
Adverse Effects:
 Flushing, diaphoresis, hypotension
 Depressed deep tendon reflexes, muscle paralysis, weakness,
lethargy, hypothermia
 Circulatory collapse, and cardiac, CNS, or respiratory depression

31. Mechanism of action:
The depletion of prostaglandins prevents
stimulation of uterus
NSAID,s e.g.Aspirin, Indomethacin,
Ibuprofen
Adverse effects
ulceration
premature closure of ductus arterious.