UTERUS

2. POSTERIOR PITUTARY HORMONE
 Oxytocin, Desamino oxytocin
ERGOT ALKALOIDS
 Ergometrine, Methylergometrine
PROSTAGLANDINS
 PGE2, PGF2α, 15-METHYL PGF2α, Misoprostol
Miscellaneous
 Ethacridine, Quinine

3. OXYTOCIN
 Oxytocin is synthesized in paraventricular nucleus of
hypothalamus
 Stored in neurohypophysis
 Released by appropriate stimuli from posterior pituitary
during
• Coitus
• Parturition
• Suckling

4. MECHANISM OF OXYTOCIN
Oxytocin
G-protein coupled receptor
ActivatePhospholipase-C
IP3
Mobilisation of ca2+
Contraction

5. OXYTOCIN – Pharmacological action
 BREAST
 Milk ejection reflex
 UTERUS
 Favours child birth
 Contraction of fundus, relaxation of lower segment and cervix
 CVS
 Conventional doses-no effect on BP
 Higher doses-vasodilatation
 KIDNEY
 Higher doses-decreased urine output

6. OXYTOCIN – Pharmacokinetics
 Inactive orally
 Administered by intramuscular or intravenous routes
 Degraded in liver and kidney
 Plasma half life is 6 minutes.
 Pregnant uterus and placenta elaborate a specific aminopeptidase
called ‘’oxytocinase’’.

7. OXYTOCIN – Uses
Induction of labour
Uterine inertia
Postpartum haemorrhage
Breast engorgement

8. OXYTOCIN – Adverse effects
 Injudicious use of of oxytocin during labor-
incompletely dilated birth canal
 Maternal and foetal soft tissue injury
 Rupture of uterus
 Foetal asphyxia
 Death
 Water intoxication

9. ERGOMETRINE
UTERUS
• Increase frequency and duration of uterine contraction
• Uterine atony is due to partial agonist action on 5-HT2 and alpha
adrenergic receptors

10. ERGOMETRINE- Pharmacological action
 CVS
• Cause vasoconstriction
 CNS
 Higher dose-produce partial agonist/antagonist interaction
with adrenergic, serotonergic and dopaminergic receptors in
brain
 GIT
• Higher doses-increase Peristalsis

11. ERGOMETRINE
Uses
• Management of third stage of labour
• To treat PPH
• Ensure normal involution
Adverse effect:
• Nausea,vomiting and rise in BP can occur
• Decrease milk secretion

12. PROSTAGLADINS
 Found in ovary, myometrium, and menstrual fluid.
 Rise in amniotic fluid during labor
Dinoprostone (PGE2)
Carboprost (PGF2α)
Misoprostol (PGE1)

13. Pharmacological Properties
 Myometrium
•During the last two trimesters of pregnancy, PGE2 or PGF2α
causes strong uterine contractions and can induce delivery of the
fetus.
•Prostaglandins are much more effective than oxytocin in the
earlier months of pregnancy.
 Cervix:
• Ripening of cervix at doses that do not affect uterine motility
• Causes softening of the cervix late in the first trimester
of pregnancy

14. Toxicity
 Stimulatory action on the smooth muscle of
the alimentary tract.
 Transient pyrexia (due to actions on
thermoregulatory centers in the
hypothalamus).
 PGF2α - hypertension.
 PGE2 - vasodilatation.

15. Therapeutic Uses
 Mid trimester abortions.
 Cervical ripening agents to facilitate normal
or induced labor.

17. UTERINE RELAXANTS ALSO
CALLED AS TOCOLYTICS
 Drugs which decreases uterine motility,
used to prevent premature labour.
 MOA;
intracellular Ca concentration
PG & OXYTOCIN

18. USES OF TOCOLYTICS
 Delays preterm labour
 Threatened abortion
 Dysmenorrhea

19. DRUGS USED
 Beta-2 Agonist
 Magnesium sulphate
 Calcium channel blockers
 Oxytocin receptor antagonist
 PG synthesis inhibitor
 Hydroxy progestrone
 Miscellaneous drugs

20. BETA-2 AGONIST
 Ritodrine
 Salbutamol
 Terbutaline
 Orchiprenaline
 Isoxsuprine

21. BETA-2 AGONIST
 RITODRINE
 MOA:
Bind to beta-2 receptors on myometrium
activation of adenyl cyclase
ATP cAMP
decreased intracellular ca and
RELAXATION

22. Dosage: started as 50 microgram I.V
maintenance dose 10milligram IM
 SIDE EFFECT;
 HR increases in mother upto 120 per min
 Palpitation, tremor, hypotension, hyperglycemia
 Pulmonary edema, arrythmia
 ISOXSUPRINE- Threatened abortion
BETA-2 AGONIST

23. MAGNESIUM SULPHATE
 Reduce convulsion and decreases BP
 MOA:
 UNCOUPLE EXCITATION CONTRACTION and causes
relaxation of myometrium
 Preferred for patient with cardiac problem,
diabetes , hypertension
 Plama conc ; 6 to7.5 mEq per L
 Flushing,sweating, headache

24. CALCIUM CHANNEL BLOCKERS
NIFEDIPINE
 Blocks L-type ca channel - RELAXATION
 INDICATION:
 Prophylaxis of recurrent premature labour
 DOSE; 10mg oral
 Side effect: Reflex tachycardia,hypotension

25. OXYTOCIN RECEPTOR ANTAGONIST
ATOSIBAN
 Competitive antagonist
 Used in preterm labour

26. MISCELLANEOUS DRUGS ARE
 DIAZOXIDE-pottasium channel opener[I.V.]
 HALOTHANE [general anaesthetic]
 NITRATES
 ETHYL ALCOHOL

28. HYDROXY PROGESTRONE
 Progestrone - physiological tocolytic in first few
trimester
 TERATOGENIC
OXYTOCIN RECEPTOR ANTAGONIST-
ATOSIBAN
 Competitive antagonist
 Used in preterm labour

29. PG SYNTHESIS INHIBITOR
 INDOMETHACIN- delays labour
 Adverse effects are
Premature closure of ductus arteriosus
Efficacy unpredictable
Oligohydramnios
Intraventricular haemorrage in newborn
 USED ONLY FOR DYSMENORRHEA