This document discusses various drugs acting on the uterus. It describes oxytocin, ergot alkaloids like ergometrine, and prostaglandins as the main classes of uterine stimulants. Oxytocin is used via intravenous infusion to induce or augment labor contractions. Ergometrine causes sustained whole uterine contraction and is used to control postpartum hemorrhaging. Prostaglandins like PGE2 and PGF2α induce rhythmic contractions and are administered intravaginally to induce abortion or labor.
7. Physiological role
• BREAST – milk ejection
CVS- Transient vasodilation & tachycardia
-Constriction of umbilical arteries and veins
CNS -Causes maternal behaviour
s
• KIDNEY – ADH like actions.
8. PHARMACOKINETICS
Not absorbed orally
Administered by i.v. , i.m. ,rarely nasal route.
Plasma t1/2- approx. 15 mins
It is primarily inactivated in the KIDNEY and the
LIVER.
DOSAGE- OXYTOCIN, SYNTOCINON 2 IU/2ml
and 5 IU/ml inj. PITOCIN 5 IU/0.5ml inj.
9. USES
Induction & Augmentation of labor:
Oxytocin DOC
i.v. infusion pump
Dilution-5 IU in 500ml NS/Glucose
0.2-2ml/mt. depending on response
contraindications:
﹡malposition
﹡cephalopelvic disproportion
﹡birth canal abnormality
10. Postpartum hemorrhage :Third stage of labour,
5 IU i.m or i.v
infusion.
Breast engorgement: Nasal spray before
suckling
Oxytocin challenge test: To assess placental
insufficiency
12. Desamino-oxytocin
Buccal formulation, uses same as oxytocin, less consistent
action.
INDICATIONS:
-Induction of labour : 50 IU every 10min, max 10 tablets
-Uterine inertia : 25 IU every 30 mins
- Promotion of uterine involution: 25-50 IU
- Breast engorgement : 25-50 IU before breast feeding
CARBETOCIN
•long acting structural analogue of human oxytocin
•given as a single IV bolus following the delivery of baby at Elective
or Emergency caesarean section.
•Carbetocin is as effective as an oxytocin infusion with respect to
blood loss following delivery
DOSE: Dilute 100mcg Carbetocin with 10mls Saline. Administer over one
minute following delivery of the baby
13. Ergometrine and Methyl ergometrine
Amine ergot alkaloid and methyl derivative.
duration of uterine contractions
Methyl ergometrine more potent action on
uterus and less on CVS, CNS, GIT etc.
ACTION
Increase force, frequency,
Moderate increase of dose→Basal tone increased
Lower segment also contracts.
14. USES
Post Partum Haemorrahge(PPH )→
After anterior shoulder presentation
Prevention → 0.2-0.3 mg i.m
Treatment → 0.5 mg i.v.
Prevent uterine atony
To promote involution in multipara →
0.125mg TDS -7days.
Diagnosis of
variant angina during Coronary
angiography
15. ADRs
Nausea, vomiting, rise in BP.
Decreases milk secretion
Avoided in Vascular disease, Hypertension,
toxemia
Sepsis→gangrene
Liver and kidney disease.
Safe in obstetrical.doses
Contraindications:
in pregnancy & early stages of labour
16. PROSTAGLANDINS
PGE2(Dinoprostone) → Vaginal application →
Induce II trimester abortion, missed abortion,
ripening of cervix in near term
Preperations-
Misoprostol → with mifepristone for early abortion
15-Methyl-PGF2α(Carboprost) → IInd trimester
abortions
Facilitate labour- Unlabelled use in cardiac, renal
disease, eclampsia.
18. 1. Oxytocin
low dosage: rhythmic contraction of uterus;
fundus contracts while cervix relaxes;
used via ivd for induction or augmentation.
high dosage: sustained contraction in whole uterus;
used via im or iv for hemostasia or restoration of
postpartum uterus.
2. Ergot alkaloids
stimulation of sustained contraction in whole uterus,
ergometrine used via po, im or iv for hemostasia or restoration of
postpartum uterus;
stimulation of blood vessel constriction,
ergotamine used via po or im for migraine.
3. Prostaglandins
PGE2 & PGF2α stimulation of rhythmic uterine contraction,
used via ivd for induction (abortion)
