Meds used in labour

Question 1

Oxytocin drug class

Oxytocin production and release site

Answer 1

Oxytoxic hormones

Produced in the hypothalamus and travels to the posterior pituitary before being released into general circulation

Question 2

Oxytocin MOA

SE of oxytocin

Answer 2

stimulates the ripening of the cervix and contractions of the uterus during labour and delivery. It also plays a role in lactation during breastfeeding

Has a similar structure to vasopressin
Excessive quantities or prolonged use of oxytocin can therefore result in anti-diuretic effects with resulting water intoxication and hyponatraemia. This is due to water being absorbed in greater quantities from the kidneys. Oxytocin can also lead to uterine hyperstimulation.

Question 3

Oxytocin clinical indications

What is syntocinon

Answer 3

Induce labour
Progress labour
Improve the frequency and strength of uterine contractions
Prevent or treat postpartum haemorrhage

Syntocinon: brand name for oxytocin

Question 4

Oxytocin contraindications

Oxytocin route of administration

Answer 4

evidence of fetal distress, fetal prematurity, abnormal fetal position (including unengaged head), placenta previa, uterine prolapse, vasa previa, cephalopelvic disproportion, cervical cancer

Given by slow intra-venous infusion using an infusion pump. Uterine activity must be monitored carefully and hyperstimulation avoided. Oxytocin can also be given intramuscularly.

Question 5

Ergometrine clinical indications

MOA?

Answer 5

Derived form ergot plants
For delivery of placenta
To reduce postpartum bleeding in PPH. Only used after the delivery of the baby

Stimulates SM contraction both in uterus and blood vessels

Question 6

Ergometrine SEs?

Contraindications

Answer 6

Hypertension
Diarrhoea
Vomiting
Angina

Avoid in eclampsia and use only in patients with significant HTN

Question 7

What is syntometrine

Answer 7

A combination drug containing oxytocin (Syntocinon) and ergometrine. It can be used for prevention or treatment of postpartum haemorrhage.

Question 8

Dinoprostone drug class

Clinical indication

MOA?

Answer 8

Prostaglandin E2

For the induction of labour: To stimulate contraction of the uterine muscles
To ripen the cervix before delivery

Act as vasodilators and lower blood pressure

Question 9

Dinopristone forms for IOL?

Answer 9

Vaginal pessaries (Propess)
Vaginal tablets (Prostin tablets)
Vaginal gel (Prostin gel)

Question 10

Misoprostol drug class

Clinical indications

Answer 10

Prostaglandin analogue

Medical management of miscarriage
Misoprostol is used alongside mifepristone for abortions, and induction of labour after intrauterine fetal death

Question 11

Mifepristone drug class

Clinicall indications

MOA

Answer 11

Anti-progestogen medication- prostaglandin analog

Induction of labour after intrauterine death or for abortions

Competitive progesterone receptor antagonist
It sensitises the myometrium to prostaglandin-induced contractions.
Mifepristone is used alongside misoprostol. It is not used during pregnancy with a healthy living foetus

Question 12

Nifedipine drug class and MOA

Clinical indications in pregnancy

Answer 12

Calcium channel blocker

Acts to reduce smooth muscle contractions in blood vessels and uterus

Reduce blood pressure in hypertension and pre-eclampsia
Tocolysis in premature labour, where it suppresses uterine activity and delays the onset of labour

Question 13

Nifedipine SEs

Nifedipine contraindications

Answer 13

Flushing
Headache
Ankle swelling

Cardiac disease such as severe hypotension or heart failure

Question 14

Terbutaline drug class ?

MOA ?

Answer 14

Beta-2 agonist: stimulates beta 2 adrenergic receptors

It acts on the smooth muscle of the uterus to suppress uterine contractions

Question 15

Terbutaline clinical indications

Answer 15

Used for tocolysis in uterine hyperstimulation, notably when the uterine contractions become excessive during induction of labour

Question 16

Contraindications to tocolysis

Answer 16

Greater than 34 weeks gestation

Non-reassuring cardiotocograph, fatal foetal anomaly or intrauterine death

Intrauterine growth restriction or placental insufficiency

Cervical dilation greater than 4cm

Chorioamnionitis

Maternal factors such as pre-eclampsia, ante-partum haemorrhage, haemodynamic instability

Question 17

Carboprost drug class?

MOA?

Answer 17

synthetic prostaglandin analogue, meaning it binds to prostaglandin receptors

Stimulates uterine contraction

Question 18

Clinical indication and route of administration of Carboprost

Answer 18

PPH where ergometrine and oxytocin have been inadequate

Given as a deep IM injection

Question 19

Contraindications to Carboprost?

Answer 19

Patients with asthma: can cause life threatening exacerbation

Question 20

TXA drug class

MOA?

Answer 20

Synthetic derivative of lysine
Antifibrinolytic that rversibly binds to lysine receptor sites on plasminogen: reduces bleeding

It binds to plasminogen and prevents it from converting to plasmin. Plasmin is an enzyme that works to dissolve the fibrin within blood clots. Fibrin is a protein that helps hold blood clots together. Therefore, by decreasing the activity of the enzyme plasmin, tranexamic acid helps prevent the breakdown of blood clots.

Question 21

TXA Clinical indications

Answer 21

Prevention and treatment of PPH
menorrhagia
Beneficial in the trauma in the first 3 hours of bleeding

Question 22

Mefanemic acid drug class and clin ind

MOA?

Answer 22

NSAID used to treat mild to moderate pain for no more than a week and primary dysmenorrhoea

Cyclo-oxegenase inhibito (COX 1 AND 2)

Question 23

Mefanemic acid side effects:

Answer 23

Diarrhoea 
Constipation 
Gassy or bloating 
Headache 
Dizziness 
Gastric ulcers