9.5 Drugs in Labour Flashcards
What secretes oxytocin?
posterior pituitary
Where is oxytocin produced?
hypothalamus
What roles does oxytocin have?
- ripening cervix
- contractions of uterus
- breastfeeding myoepithelial cells “let-down” / contract to release milk
When are infusions of oxytocin used?
- induce labour
- progress labour
- improve freq. and strength of contractions
- prevent of treat PPH
What is a brand name of oxytocin?
Syntocinon
What is a oxytocin receptor antagonist and when might you use it?
Atosiban is oxytocin receptor antagonist
for TOCOLYSIS in premature labour (when nifedipine is CI)
What is often used after delivery in the 3rd stage to prevent / reduce PPH?
Ergometrine - stimulates smooth muscle contraction
What are the side effects of ergometrine?
- HTN
- diarrhoea
- vomiting
- angina
When is ergometrine CI?
CI in eclampsia and caution with in HTN.
What is the name of ergometrine mixed with oxytocin for PPH?
Syntometrine
What effect do prostaglandins have on the body?
- stimulate contraction of uterus
- ripen cervix
- vasodilator
What is the name of the prostaglandin used in IOL?
dinoprostone or prostaglandin E2
What forms can dinoprostone come in?
pessaries - Propess
tablets - Prostin
gel- Prostin
(prostaglandin E2)
What medication opposes the action of prostaglandins?
NSAIDs inhibit action of prostaglandins
What can NSAIDs be used for?
- avoid in pregnancy, can raise BP
- useful in dysmenorrhea as they reduce painful cramping
What drug is a prostaglandin analogue?
Misoprostol is a prostaglandin analogue
What is misoprostol used for?
- medical management of miscarriage
- alongside mifepristone for abortions
- IOL after IUD
What is the MOA of mifepristone?
anti-progestogen (blocks progesterone action) so:
- halts pregnancy and ripens cervix
enhances effects of prostaglandins so:
- stimulates contractions of uterus
What is mifepristone used for?
- alongside misoprostol for abortions
- IOL after IUD
What two uses does nifedipine have?
- reduce BP in HTN of PET
- tocolysis in prem labour
(calcium channel blocker reduces smooth muscle contraction in vessels and uterus)
What is the MOA of terbutaline?
beta-2 agonist (similar to salbutamol)
Stimulates beta-2 ADR receptors
- acts on smooth muscle of uterus to suppress contractions –> tocolytic
When is terbutaline used?
tocolysis in uterine hyperstimulation eg excessive contractions during IOL
What is the MOA of carboprost?
synthetic prostaglandin analogue
What is carboprost used for?
deep IM injection in PPH when ergometrine and oxytocin have been inadequate.
When should carboprost be avoided?
In patients with a history of asthma - can trigger life threatening exacerbation
What is the MOA of tranexamic acid?
antifibrinolytic
it binds to plasminogen and prevents in converting to plasmin (plasmin enzyme breaks down fibrin clots)
What is tranexamic acid used for in labour?
prevent and treat PPH.
prevents breakdown of clots by blocking plasmin formation
