1. Drugs used in obstetric
emergencies
Vasanthakumari,Msc (N)
Lecturer(pediatrics)
Sri manakula vinayagar nursing clg,pudhucherry.

2. Drugs in Pregnancy
FIRST TRIMESTER :
congenital malformations (teratogenesis)
SECOND & THIRD TRIMESTER :
affect growth & fetal development or
toxic effects on fetal tissues
NEAR TERM :
adverse effects on Labour or
neonate after delivery

3. Drug categories
Category –A
- practically Not harmful
during any trimester of pregnancy.
eg- antibiotics( penicillin, ampicillin,
amoxicillin, cloxacillin,
erythromycin stearate,
cephalosporin)
vitamin and mineral in standard
doses
Thyroxin and humanized insulin

4. Conti….
Category B
eg-
- used in pregnancy with out
adverse effect
metronidazole, tinidazole,
azithromycin,
nystatin, paracetamol,
ranitidine, ritodrine,

5. Conti…..
• Category – C
- Shown adverse fetal effects in
the animal model, but no adequate studies in
pregnant women
•
- immediate benefits have to be
weighed against the potential risks of drug used
• Eg- trimethoprim, anti tuberculosis
drugs, norfloxacin, ciprofloxcin,lfloxacin,
– aminophylline, quinine, acyclovir, zidovudine,heparin,
– hydralazine, Beta blockers, MAO- inhibitors,
lorazepam etc.

6. Conti..
• Category –D - known to be potentially harmful.
Evidence of positive fetal risks. Certain situation
maternal benefits may outweigh the potential fetal risks.
• Eg –
Tetracycline's, streptomycin, kanamycin,
phenytoin,phenobarbitone,
valproicacid, alprazolam,chlordiazepoxide,
lithium, tricyclic depressants, ACE inhibitors,
spironolactone, propyl thiouracil, corticosteroids,
tobacco, iodine, warfarin, thiazides, alcohol,
etc.

7. Conti…….
• Category- X - proven to exert harmful effects
on the fetus in both animal and humans.
• Fetal risks outweigh any possible benefits to mother
• Hence should be avoided.
Eg.
Aminoptterin.,androgens,clomphene,diethylstilboestrol,
oestrogens,antimalignancy drugs,
substance abuse, such as heroin,opium,lysergic acid
diethylamide,etc
used by drug addicts.

8. Definition of
Obstetric Emergencies:
• An emergency is an occurrence of serious
and dangerous nature, developing suddenly
and unexpectedly, demanding immediate
attention.

9. Obstetric emergencies related directly to
pregnancy include, for instance
1. Pre-eclampsia
2. Eclampsia
3. Antepartum Haemorrhage
4. Postpartum Haemorrhage
5. Amniotic Fluid Embolism
6. Congenital Heart Disease
7. Epilepsy

10. Uterotonics and tocolytics drugs
• Uterotonics increase uterine contractions
(oxytocine, prostaglandines, serotonine,
kinines, cathecholamines).
• Tocolytics decrease uterine contracions
(spasmolytics, beta-receptor-stimulating
medications, anti-oxytocin drugs).

11. Medications for Uterine Atony
NE
I
OXYTOCIN
“The Champ”
Cytotec
Inexpensive (?) Effective
RG
H E y”
ET e d
M pe
“S

12. Mechanism of myometrium
contractions
• Myometrium has alpha and betaadrenoreceptors.
• Stimulation of alpha-receptors by
catheholamines causes uterus contraction
• Stimulation of beta-receptors by
catheholamines causes uterus relaxation

13. Mechanism of myometrium
contractions
• Uterus body contains alpha and beta catheholamines
receptors
• Lower segment contains choline and
serotonine receptors
• Cervix contains chemo-, baro- and
mechanoreceptors

14. Severe Pre eclampsia / HTN
• IV Labetolol (ß blocker):
- Side effects: headache, nausea, vomiting, postural
hypotension & liver damage
- Contraindication: Asthma, marked bradycardia
• IV hydralazine (vasodilator) :
- Side effects: headache,nausea, vomitting, dizziness,
flushing, tachycardia, palpitation & hypotension
- Because of hypotension preload with gelofusin adv.
- Contraindication- SLE, severe tachycardia & MI

15. Nifedipine
• Calcium Channel blocker
•
•
•
•
Clinical use:
Mild to moderate- 5-20 mg TDS/PO
Severe HTN- 10 mg Retard/PO
Tocolytic- Incremental doses every 20 min until
contraction stop, then 20 mg TDS/PO
• Side effects: Headache,dizziness,palpitation,
tachycardia, hypotension,sweating & syncope.

16. Magnesium Sulphate
• Clinical use: Prevention & treatment of seizure in
eclampsia / severe pre eclampsia
• Dose: 4g IV stat then 1g/hr to be continued 24hr after last
seizure
• Side effects: nausea,vomiting,flushing,
drowsiness,confusion,loss of tendon reflexes,
hypotension, decrease U/O, respiratory depression,
arrhythmias,cardiac arrest
• Because of toxicity, Mg levels monitored

17. Magnesium Sulfate
•
•
•
•
•
• Mech of action is unclear
– Impedes acetylcholine release?
– Decr sens of the motor end plate?
– Central anticonvulsant effect?
• 4 g iv bolus(20 cc of 20% soln) over 1015min
• • Maintenance is 1-3 g/h(alt 10 g im)

18. MgSo4
• First line treatment of eclampsia
• • Recommended as prophylaxis against
• eclampsia in severe pre eclampsia

19. MgSo4
•
•
•
•
•
•
•
• Cochrane reviews: MgSo4 safer and more
effective than diazepam or phenytoin for
prevention of recurrent seizures
• SE: Mg toxicity
– Loss of DTRs @ 8-10 mEq/L
– Respiratory paralysis @10-15 mEq/L
– Cardiac arrest @ 20-25 mEq/L

20. MgSo4
•• Monitor:
•– RR hourly
•– Patellar reflexes hourly
•– U/O <20cc/hr--decrease dose
•– Serum Mg levels q 4 hrs 94-8mEq/L)
•• Crosses the placenta freely--rarely NN
•depression
• Calcium gluconate--1g iv over 3-5 min(10cc of
10% soln) antidote!

21. Post partum hemorrhage
• Postpartum Haemorrhage- uterotonicsoxcyticin
• 0.2 mg IM/IV q2-4hr PRN; not to exceed 5 doses,
THEN 0.2-0.4 mg PO q6-8hr PRN for 2-7 days
• Administer IV only in emergency because of
potential for Hypertension & CVA
• Administer over >1 minute and monitor BP
• Refractory Cluster Headache (Off-label)
• 0.2 mg PO q6-8hr, not to exceed 6 months

22. OXYTOCIN
OXYTOCIN
“The Champ”
• The common medication used to
achieve uterine contraction
• First-line agent to prevent and
treat PPH

23. Oxytocin
•
•
•
•
Mechanism of action:
Acts through oxytocin receptors present in
smooth muscles of myometrium.
Stimulates the amniotic and decidual
prostaglandin production.
Mobilization of bound intracellular calcium from
sarcoplasmic reticulum to activate the contractile
protein.
There is increase in frequency and force of
uterine contractions, similar to physiological
uterine contractions

24. Oxytocin
Duration of action: approximately 20 minutes. In non
pregnant women, half life (t1/2) is 10-15 minutes and the
removal from circulation is due mainly to kidneys and liver,
but t1/2 in pregnant women is only 3 minutes, because of
presence of enzyme oxytocinase in placenta, uterine tissue
and plasma which inactivates it.
• Given orally it is ineffective as it is inactivated rapidly in the
Gastro-intestinal tract by enzyme, trypsin, needs to be
administered by parenteral, nasal or buccal routes.
Unitage and Preparation: 1 international unit (i.u.) of oxytocin
is equivalent to 2 microgram of pure hormone.
• Commercially available preparation is produced synthetically.
Oxytocin injections are available in concentration of 5 i.u. / ml
(Syntocinon) , 5 i.u/ 0.5ml. (pitocin) or 2 i.u./ 2ml. (oxytocin).
• Oxytocin nasal spray contains 40 units/ ml.

25. Oxytocin
Indications for stopping the infusion

•
•
•


Abnormal uterine contractions
occurring too frequently ( less than every 2 minutes),
lasting more than 60 seconds ( hyper stimulation)
and increased tonus in between the contraction
Evidence of Foetal distress
Appearance of untoward maternal signs and symptoms

26. Oxytocin
Dangers of Oxytocin
Maternal
• Uterine hyper stimulation; increased frequency and duration
of uterine contractions & / or increased tonus, is often
associated with abnormal foetal heart rate pattern
• Urine rupture; high risk in grand multipara, malpresentation,
contracted pelvis, prior uterine scar and excessive dosages.
• Water intoxication; due to its ADH like antidiuretic action,
when used in high dosages i.e. 30 – 40 i.u. / min., manifested
by hyponatremia, confusion, convulsions, coma, CHF and even
death. Can be prevented by strict intake output record, use of
salt solutions, and by avoiding high doses oxytocin for a longer
time.

27. • Hypotension; it is seen with bolus i.v. injection
especially when the patient is hypovolemic or in
patients with heart disease. Occasionally may
produce anginal pain.
• Anti- diuresis; especially with higher dosages
Foetal
• Foetal distress, foetal hypoxia or even foetal death
may occur due to reduced placental blood flow due
to uterine hyper stimulation.

28. Oxytocin (Syntocinon)
• Octapeptide
• Strong rhythmical contraction of myometrium
• Large doses- sustained contraction(↓ placental blood
flow & fetal hypoxia/death)
• Clinical use:
- IOL (IVI 3U syntocinon+50 ml of saline)
- Augment slow labour (IVI same as above)
-3rd stage of labour- 5 U IM for HTN ,cardiac disease
- IVI 40 U in 500ml saline ( PPH)
-Surgical termination of preg./ERPC- 5U slow IV

29. uterotonics- methylergonovin
• Postpartum Haemorrhage
• 0.2 mg IM/IV q2-4hr PRN; not to exceed 5 doses,
THEN 0.2-0.4 mg PO q6-8hr PRN for 2-7 days
• Administer IV only in emergency because of
potential for Hypertension & CVA
• Administer over >1 minute and monitor BP
• Refractory Cluster Headache (Off-label)
• 0.2 mg PO q6-8hr, not to exceed 6 months

30. •
•
•
•
carboprost tromethamine (Rx) - Hemabate
Refractory Postpartum Uterine Bleeding
Initial 250 mcg IM, repeat PRN q15-90min
No more than 2000 mcg or 8 doses

31. • misoprostol (Rx) - Cytotec
• Postpartum Hemorrhage (Off-label)
• Prophylaxis: 600 mcg PO within 1 minute of
delivery
• Treatment: 800 mcg PO once; use caution if
prophylactic dose already given and adverse
effects present or observed
• Use only in settings where oxytocin not
available

32. • ergonovine (Discontinued) - ergometrine, Ergotrate
• Pospartum or Postabortion Hemorrhage
• 0.2 mg IM; may repeat in 2-4hr; not to exceed 5 doses
total
• Give IV only in emergency because of potential for
HTN & CVA
• Alternatively, 0.2-0.4 mg PO q6-12hr PRN for 48 hr or
until danger of uterine atony has passed; no more than
1 week
• Give over >1 minute & monitor BP

33. Dinoprostone ( prostin E2)
• Vaginal pessary/gel
• Clinical use: IOL – 3mg 6hrs apart ( no more than
2 pessaries in 24hrs and max. 3 doses)
• Side effect: Nausea ,vomiting, diarrhoea, fever,
Uterine hyperstimulation , HTN, bronchospasm
• Advantages :
- Mobile patient
-Reduce need for syntocinon

34. Carboprost ( Hemabate)
• Dose ; 250µg deep IM repeated every 15 min
max 8 doses.
(OR Intra-myometrial use at C/S)
• Side effects: Nausea ,vomiting, diarrhoea, fever,
bronchospasm, dyspnoea, pulmonary oedema,
HTN, cardiovascular collapse
• Clinical use: Postpartum haemorrhage

35. Atosiban(Tractocile)
• Oxytocin receptor antagonist
• Inhibition of uncomplicated preterm labour
between 24-33 weeks ( Tocolytic)
• Contraindication: severe PET, eclampsia, IUGR,
IUD, placenta previa, placental abruption,
abnormal CTG, SROM after 30/40
• Side effects: Nausea,vomiting,headache, hot
flushes, tachycardia, hypotension &
hyperglycemia
• Dose- Stat IVI then continue infusion until no
contraction for 6 hrs.

36. Other tocolytics
• Salbutamol inhaler- 100 mcg x 2 puffs stat
• Terbutaline- 250 mcg subcutaneous
• Clinical use: both drugs are used for short term.
(i) relaxing uterus at C/S
(ii) ECV procedure
• Side effects: Headache, palpitation, tachycardia,
MI ,arrhythmias, hypotension & collapse

37. Mild /Moderate HTN/PET
• Methyldopa:
-Dose: 250mg BD/TDS , PO max dose 3g /day
-Side effects: Headache,dizziness,dry mouth , postural
hypotension,nightmares, mild psychosis,
depression,hepatitis & jaundice
- Important to stop drug in postnatal period
• Labetolol 100-200mg BD/TDS PO max 2.4g/24hr
• ACE inhibitors are contraindicated in pregnancy

38. Don’t forget
analgesia & anaesthesia
for labour & delivery!!

39. Commonly used drugs that should be avoided in
pregnancy and safer alternatives
Drug class
Drugs to avoid in
pregnancy
Associated
problems
Drugs considered
safer alternatives
analgesics
Non steroidal anti
inflammatory
Increased risk of
spontaneous
abortion
Paracetamol,
opiates
antibiotics
trimethoprim
Causes structural
defects-cleft palate
Penicillin and
cephalosporin
anticoagulants
Warfarin(1st
&3rd trimester)
Low molecular
weight heparin
anticonvulsants'
phenytoin
CNS defects,
hemorrhage,
stillbirth,
spontaneous
abortion,
prematurity.
Congenital facial
anomalies
Cardio vascular
drugs
amiodarone
carbamazepine
Cardiac arrhythmias digoxin
and growth
restriction

40. Antibiotics categorized according to their safety
profile
Name of the drugs
category
remarks
Ampicillin, cephalexin,
amoxycillin,
erythromycin,
chloramphenicol,
clindamycin.
A
May be prescribed safely
Tinidazole,
trimethoprim +
sulphonamides
C
Preferably avoided
Tetracycline,
aminoglycosides,
doxycycline
D
Should always be avoided

41. Drugs in early pregnancy
• Mifepristone- 200mg PO
• Mechanism:
Antiprogestogenic steroid
Sensitizes myometrium to prostaglandin-induced
contractions & ripens the cervix
• Clinical use:
Medical termination of pregnancy
Medical management of miscarriage/IUD
• Side effects: Gastro intestinal cramps, rash, urticaria,
headache,dizziness,
• Contraindication: severe asthma

42. Misoprostol
• Synthetic prostaglandin
• PO/PV route
• Clinical use:
- Medical TOP
- Medical management of miscarriage/ IUD
( For 1st trimester single dose of 400mcg
From 12- 34 weeks 400mcg 3hrly ,max 5 doses)
- Postpartum hemorrhage- 800mcg PR/PV
• Side effects: nausea,vomiting, diarrhoea, abdominal pain

43. Methotrexate
• Cinical use: Medical management of ectopic
pregnancy
• Dose 50mg per kg/m2
• Criteria- adenexal mass, non viable pregnancy
hCG< 3000U, haemoperitonuem < 150ml
• Side effects:
• Disadvantage : repeated hCG levels, emergency
surgery
• Advantage: Avoid surgery, tube preserved

44. Menorrhagia / dysmenorrhea
• Mefenamic acid:
- NSAID, reduces bleeding by 25%
- Dose: 250-500mgx TDS D1-3 of cycle or PRN
- Side effects: Gastro-intestinal discomfort nausea,
diarrhoea, bleeding/ulceration
• Tranexamic acid:
- Antifibrinolytic,reduces bleeding by 50%
- Dose: 1g TDS/QDS D1-4 of cycle
- Contraindication: thromboembolic disease
- Side effects: nausea,vomiting,diarrhoea, thrombo
embolic event

45. Progestogens
• Dysfunctional uterine bleeding/menorrhagiaNorethisterone 5mg TDS D5-25 (3ks on/1wk off)
• Endometriosis- same dose contin. 9 months
• Menorrhagia- Depoprovera, Mirena
• Contraception- Mini pill, Mirena
• Induce withdrawal bleeding eg. PCOS ( 10 days Rx)
• Endometrial hyperplasia ( except atypical variety)- Depo
provera, Mirena
• HRT
• Women with previous preterm labours -cyclogest pessary
200mg PV/PR daily till 36 weeks
• Following IVF/ICSI- Gestone inj + cyclogest pessary

46. Progesterone
• Increases membrane potential of myocyte and particularly
blocks impulses between myocytes
• Myometrium becomes insensitive to irritatons
myometrium

47. Estrogen
•
•
•
•
•
•
•
Contraceptive - COC
DUB/menorrhagia-COC
Endometriosis- COC continued for 9 months
PCOS/Hirsutism - Dianette
PMS- E2 patches + Mirena
HRT
Hypogonadism- cyclical therapy initially oestogen
then combined oestrogen & progesterone

48. Gonadorelin analogue
• Mechanism- Initial stimulation then down regulation
of GnRH receptors reducing the release of
gonadotrophins and in-turn release of estrogen &
androgen production
• Side effects:menopausal symptoms, headache,
hypersensitivity( rash,asthma, anaphylaxis),
palpitation,hypertension,breast tenderness & GI
symptoms, irritation of nasal mucosa (spray)
• E.g Prostap, Zoladex & Buserelin spray
• S/C /IM inj. Monthly or nasal spray TDS for 6/12
• Maximum treatment no more than 6 months

49. Gonadorelin analogue- clinical use
•
•
•
•
•
Endometriosis
Chronic pelvic pain
Prior to myomectomy- size & bleeding
Prior to hysterectomy for fibroids
Infertility- pituitary desensitisation before induction
of ovulation by gonadotrophin for IVF
• Menorrhagia in perimenopausal women
• Precocious puberty

50. Danazol
• Mechanism: Inhibits pituitary gonadotrophin
-antioestrogenic & antiprogestogenic
- androgenic activity
• Dose : 200-800mg 4 divided dose for 3-6 month
• Clinical use:
- Endometriosis
- Benign fibrocystic disease(breast tenderness)
• Side effects: Nausea, headache,dizziness, weight gain, libido changes,
androgenic side effects ( acne, oily skin, hair loss,voice changes)

51. HRT
• Benefits:
- Systemic therapy- improves vasomotor symp.
- prevents osteoporosis
- Vaginal cream/ pessary - atrophic vaginitis/ urinary symptoms
• Risk of HRT:
- Breast Ca(6 additional cases in 50-59 old , 5 yr use)
- Ovarian Ca (1)
- Endometrial Ca(unopposed E2)
- VTE (7)
- Stroke (1)
- Coronary heart disease(15 ,70-79yr)

52. HRT
• Route-Tab,gel,patches,implant,vaginal pessary/cream
• Conventional HRT prep: E2 +12 days P
: Combined E+P
• Sequential HRT:
- Indication: Perimenopausal women with uterus
- Regular withdrawal bleeding
• Continuous combined:
- Indication: Postmenopausal (>1yr) with uterus
- Bleed free

53. Other HRT
• Raloxifene: SERMs
- Post menopausal women>1 yr
- Prevents osteoporosis
- less risk of breast Ca
- Not effective for vasomotor symptoms
- Same risk of VTE as other HRT
• Tibolone
- Synthetic prep with oestogenic,progestogenic &
androgenic effect
- Same benefits & risks as HRT
- Improves libido

54. Management of vasomotor symptoms
of menopause
•
•
•
•
•
•
Systemic HRT
Tibolone
Clonidine
Venlafaxine
Fluoxetine
Not recommended- ginseng,Kosh,Soya prep( ?
safety)

55. Anticholenergics for Urge incontinence
• Preparations:
- Tolterodine (Detrusitol XL) 4mg/OD
- Solifenacin(Vesicare) 5-10mg OD
- Trospium chloride(Regurin) 20mgBd
- Oxybutynin- tab 2.5 mg OD
- patches 36mg twice weekly
• Side effects: dry mouth,constipation,blurred
vision,dry eyes,drowsiness,dizziness & palpitation

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