Tocolytics and oxytocics Flashcards
Tocolytics
Uterolytic, anti contraction, labour suppressants, to delay preterm birth (37 weeks) by relaxing smooth uterine muscle
Effective 48 hours (allows for steroids to accelerate development) all work by decreasing amount of myosin available to interact with actin
Oxytocics
Utertonic, used to induce contraction
5 classes of tocolytics
Beta 2, CCB, COX inhibitors, Oxytocin receptor antags, NO donors
Drugs that cause decreased release of calcium from sarcoplasmic reticulum
CCB, COX inhibitors and oxytocin
B2
Increases cAMP that leads to suppression of myosin LC kinase which results in reduced contraction intensity and frequency
CCB sides
Tachycardia, facial flushing, headache, dizziness, nausea
Indomethacin
COX inhibitor, risk of sides so second line, given PR, inhibits prostaglandins which reduces uterine contraction
Atosiban
Inhibitor of oxytocin and vasopressin
Inhibits oxy mediated release of inositol TP from myometrial cell which reduces Ca from SR and reduced influx of Ca from extraceullar space through on gated channels
Very safe
Progesterone and antibiotics
Can delay labour, progesterone MOA is unknown
Antibiotics for vaginosis as it is associated with preterm labour and delivery
Preeclampsia
HTN, fluid retention, proteinurea
Eclampsia
Seizures in preggos with HTN followed by coma
Mag tocolytic
No longer recommended, MOA unknown, minimially effective with high risks
Mag MOA
Inhibits ACh at NMJ by competing with calcium for binding at calcium channels, decreased BBB permeability which in turn decreases cerebral edema, antagonizes NMDA in CNS
Mag adverse effects
Hypotension, flushing, headache, dizzy, lethargy, dry mouth, rise in body temp
Mag contras and doses
Heart block/renal failure
4g in 50ml of 20
Maintenance 5g in 250mL over 60
2g in 50mL of 20 for ongoing seizures
