Oxytocics and Tocolytics Flashcards
What are oxytocics?
Drugs that contract uterine muslces
Name three classes of oxytocics.
Oxytocins
Ergot derivatives
Prostaglandins
Where do oxytocics act?
Myometrial oxytocin receptor
voltage mediated calcium channels
What physiological change happens during labour that is beneficial for the administration of oxytocics?
There is a 100-200 fold increase in myometrial oxytocin receptors during labour.
What is the name of synthetic oxytocin?
Syntocinon
Name a combo type of oxytocin and what it contains
Syntometrine = oxytocin + ergometrine
Three indications of oxytocins
To induce a miscarriage or accelerate abortion
To induce labour
During the puerperium period, to minimise blood loss
Compications of oxytocins
Uterine hyperstimulation:
- hypertonia aka increased DURATION of contraction
- polysystole = increased frequency of contraction
Uterine rupture - violent uterine contractions
What releases the oxytocin?
Paraventricular nucleus of the hypothalamus creates the OT, then the POSTERIOR PITUITARY releases it.
What stimulus is needed to release oxytocin naturally?
Stretching of the uterus stimulates the PVN to release
Which drugs are used to induce miscarriage?
Gemeprost
Which drug is used in the medical termination of pregnancy?
Misoprostol
Mifepristone
MOA of misoprostol
Synthetic prostaglandin analgoue
MOA of mifepristone
Progesterone + glucocorticoid receptor anatagonist.
What drug is used to induce labour?
Dinoprostone - tablets, pessaries, or vaginal gel
Is Prostin E2 vaginal gel bioequivalent to Prostin E2 vaginal tablets?
No - if you take time x, the level in the body would be different.
What drug is used to induce or augment labour? What is done with this?
Oxytocin - ARM - assisted rupture of membranes aka amniotomy
Oxytocin drug delivery
Slow IV infusion
Complications of oxytocin
hyperstimulation of the uterus
excessive fluid retention
3 drugs used in labour induction
Dinoprostone
Oxytocin
Misoprostol (unlicensed)
Drug during prevention or treatment of bleeding with incomplete miscarriage
Ergometrine + oxytocin IM
(Syntometrine)
Drug used in third stage of labour to reduce risk of PPH
Ergometrine 500mcg + oxytocin 5units IM
(Syntometrine)
When is syntometrine contraindicated and why?
In pre-eclampsia as ergometrine can increase BP as it is a vasoconstrictor
If a pt is unresponsive to syntometrine but has a PPH, what can you give?
Carboprost 250mcg/ml injections
OR misoprostol but this would be unlicensed.
What drug is used for the prevention of uterine atony after c -section?
Carbetocin 100mcg IV
Name a tocolytic used for inhibition of uncomplicated premature labour
Atosiban
Name some other drugs used as tocolytics
Nifedipine
Salbutamol
Terbutalne
Indomethacin
