drugs in labour

what drugs are used in labour?

- oxytocin

- ergometrine

- prostaglandins

- misoprostol

- nifedipine

- terbutaline

- carboprost

- tranexamic acid

what does oxytocin do?

- stimulates ripening of the cervix

- stimulates contractions of the uterus

- lactation

what is oxytocin used for in labour?

- induce labour

- progress labour

- improve frequency and strength of uterine contractions

- prevent or treat postpartum haemorrhage

what does ergometrine do?

stimulates smooth muscle contraction in uterus and blood vessels

what is ergometrine used for?

delivery of placenta and reduce postpartum bleeding in third stage of labour and postpartum

can it be used in the first or second stages of labour?

no - only after the delivery of the baby

what are the side effects of ergometrine?

due to action on smooth muscle in blood vessels and GI tract

- hypertension

- diarrhoea

- vomiting

- angina

when should ergometrine be avoided?

eclampsia - and used with significant caution in pts with hypertension

what is syntometrine?

combination of oxytocin and ergometrine

what is syntometrine used for?

prevention or treatment of PPH

what do prostaglandins do?

- stimulate contraction of the uterine muscles

- aid cervix ripening before delivery

- vasodilation

what is a key prostaglandin which is used to induce labour?

dinoprostone - prostaglandin E2

what forms do prostaglandins come in?

- vaginal pessaries

- vaginal tablets

- vaginal gel

what do NSAIDs do to prostaglandins?

inhibit the action of prostaglandins

what do NSAIDs therefore do?

increase blood pressure

who are NSAIDs avoided in?

pregnancy and delivery in women with high BP

what is misoprostol?

prostaglandin analogue

when is misoprostol used?

for induction of labour in:

- miscarriage

- abortions

what is mifepristone?

progesterone antagonist

what is mifepristone used for?

induce labour in:

- abortions

- miscarriage

what is nifedipine?

calcium channel blocker

what does nifedipine do?

reduces smooth muscle contraction in blood vessels and uterus

what is it used for in pregnancy?

- reduce bp (second line after labetolol)

- tocolysis in premature labour

what is terbutaline?

beta-2-agonist (like salbutamol)

what is the moa of terbutaline?

stimulates beta-2 adrenergic receptors on smooth muscle of uterus to suppress uterine contractions

when is terbutaline used?

tocolysis in uterine hyperstimulation - when uterine contractions have become excessive during labour

what is carboprost?

synthetic prostaglandin analogue

what does carboprost do?

stimulates uterine contractions

when is it used?

postpartum haemorrhage - if ergometrine and oxytocin are inadequate

when is carboprost contraindicated?

asthma

what is tranexamic acid?

antifibrinolytic

what is the moa of tranexamic acid?

binds to plasminogen and prevents it from converting to plasmin

what does plasmin usually do?

dissolved blood clots

therefore when is tranexamic acid used?

prevention and treatment of PPH

what is used to reduce BP in labour?

IV labetolol

what is the target bp in labour?

135/85