Drugs that affect uterine motility (Contractility) Flashcards
Uterine stimulants
promote/stimulate uterine contractility
Oxtyocics
oxytocin, pitocin, syntocinon
Therapeutic actions of Oxytocics
promote an increase in force, frequency and duration of uterine contractions
- initiates and or stimulates uterine contractions
- stimulates milk letdown reflex
Pharmacokinetics of Oxytocics
functions similarly to natural oxytocin (hormone produced in hypothalamus & stored in posterior pituitary)
- absorption- well absorbed from nasal mucosa
- distribution
- widely distributed in extracellular fluid
- small amounts reach fetal circulation
- metabolism/excretion- rapidly metabolized by kidney adn liver
- half life 3-9 minutes
Indications for use of Oxytocics
- Induction of labor- initiate uterine contractions prior to spontaneous onset of labor and/or contractions that will lead to labor and delivery
- Increase effectiveness of contractions- when inadequate or ineffective uterine contractions during labor
- Postpartum- control bleeding and promote involution
- Stimulation of milk letdown reflex- in breastfeeding mothers
Drug interactions of oxytocics
- severe hypertension may result if oxytocin given after administration of vasopressors
- Hypotension may result if used concurrently with cyclopropane anesthesia
Complications/ side-effects of oxytocin
- anti-diuretic effect- non electrolyte IV solutions should not be used for infusions may lead to water intoxication
- increased cardiac output which may lead to increased blood pressure
- IV bolus may lead to decreased blood pressure and tachycardia
- Increase chance of neonatal hyperbilirubinemia
- increased risk f abnormally strong or titanic contractions which leads to fetal distress (also placental perfusion decreases)
- Uterine overstimulation
- Increased risk of uterine rupture
- Increased chance of placental abruption
- associated with increased risk of epidurlal anesthesia and increased risk of c-section
Contraindications of Oxytocics
- Abnormal fetal lie, CPD, or cord presentation
- Prior surgery or trauma to the uterus
- Placental abnormalities- complete placenta previa or if a complete placental abruption has occurred or is suspected
- Non-reassuring FHR, fetal distress; and or positive stress test (OCT)
- Active gental herpes
- Abnormalities of uterus, cervix, pelvis, or vagina that are not compatible with a vaginal delivery
- Invasive cervical cancer
Implications of Oxytocics
*THE FDA RECOMMENDS THE USE OF PITCOIN ONLY WHEN MEDICALLY INDICATED. IT SHOULD NOT BE GIVEN FOR ELECTIVE INDUCTION OF LABOR
Indications for use when initiating labor
- Inadequate uterine contractions after PROM
- Post- term fetus or IUGR
- Fetus is jeopardy if no delivered ASAP
- Maternal medication problems ( severe Rh incompatibility, isoimmunizaton, diabetes or renal disease
- Preeclampsia/Eclampsia and or HELP
- intrauterine fetal demise (stillbirth)
- Logistics- history of precipitous labors (especially when must travel long distance for delivery)
Favorable indicatiors
conditions necessary for successful induction
- Bishops Pelvic Score- the higher the score the greater the chance of a favorable outcome
- 0 to 3 for each of area
- cervical dilation
- cervical effacement
- cervical consistency (firm, medium, or soft)
- station- related to ishial spines
- position (posterior vs anterior)
Nursing interventions/ responsibilities related to Oxytocics
- monitor contractions- frequency, duration, and strength
- Give IV piggyback with infusion pump
- Monitor FHR and maternal vital signs
- Stop infusion if unfavorable FHR
- Use electrolyte solution to lessen chance of antidiuretic effect
- monitor for water intoxication
Ergot Alkaloids
- sustained uterine contractions
- Methylergonovine (Methergine)
- Ergotrate ( Ergonovine)
Pharmacokentics of Ergot alkaloids
- effect uterine and smooth muscle stimulates adrenergic, dopaminergic, and serotonergic receptors which results in
- stimulation of uterine contractions
- constriction of arterioles and veins
Drug interatctions with Ergot alkaloids
- parenteral sympathomimetics and other ergot alkaloids administered together to result in increased vasomotor action and can lead to hypertension
Indication of use of Ergot alkaloids
- post abortion and postpartum period only
- increase uterine tone
- decrease bleeding
Adverse side effects of Ergot alkaloids
- SEVERE HYPERTENSION
- bradycardia
- N/V
- seizures and gangrene with overdose
Contraindications of Ergot alkaloids
- prior to delivery of placenta
- if there is uterine sepsis
- for threatened spontaneous abortion
- if preeclampsia/eclampsia
Nursing implications/ considerations of Ergot alkaloids
- Caution if history of cardiovascular, renal or hepatic dysfunction
- Due to adverse side effects- usually reserved for use with severe and/or life threatening uterine bleeding
- Monitor vital signs and uterine response during and after parenteral administration until patient stabilized (usually 1-2 hrs)
Prostaglandins
Hormone which are synthesized in all body tissues
clinical uses are limited- usually given in conjunction with oxytocin
Therapeutic actions of Prostaglandins
- Induce abortion
- Evacuate uterus with missed abortion, begin hydatidiform mole, or intrauterine fetal death up to 28 weeks gestation
- induce cervical ripening
- control postpartum hemorrhage
- stimulates myometrium (smooth muscle layer of uterus) to contract and lead to hemostasis at placental attachment site
Pharmacokinetics of Prostaglandins
mechanism of action not fully determined
Drug interactions of prostaglandins
increases action of oxytocic drugs
Prostaglandins Contraindicated for patients with
- acute pelvic inflammatory disease (PID)
- Uterine fibroids
- Cervical stenosis
- Cardiac pulmonary, renal or hepatic disease
Adverse side effects of Prostaglandins
- Dizziness, headache, fainting flushing
- acute hypertension chest pain and dysrthymias (Due to stimulation of smooth muscle)
- sustained uterine contractility may lead to cervical lacerations and uterine ruputre
Nursing implications of prostaglandins
- administered intravaginally after warmed to room temperature
- carefully monitor uterine activity and fetal status ( hypertonic contractions and fetal distress)
Prostaglandins most commonly utilized:
- Dioprostone (cervidil, prepidil gel)
- Misoprostol (cytotec)
- Carboprost tromethamine (hemabate, prostin/15m)
Misoprostol
- cervical ripening is unlabeled use
- oxytocin may be started 1 hour after 1st dose
- decreased acid secretion and protects GI mucosa ( most commonly used for NSAID-induced ulcers)
- most common side effects are diarrhea and abdominal pain
Carboprost tromethamine
dose: 250 mcg IM (Deep IM)
- induce pharmacologic abortion between 13-20 weeks
- control postpartum bleeding
* most common side effects is vomiting and diarrhea
Progesterone Receptor Antagonist
Mifepristone (Mifeprex, RU-486) synthetic steroid/abortifacient
- medical termination of pregnancies up to 49 days gestation
- softening and dilation of the cervix prior to mechanical cervical dilation for pregnancy termination
- labor induction when fetal death inutero
- prevents ovulation when taken daily (2mg/day)
- 10 mg given prior to ovulation delays ovulation by 3-4 days
Most common side effects
nearly all women experience abdominal pain uterine cramping, vaginal bleeding and spotting for an average of 9-16 days
In medical abortion blockage of progesterone receptors directly causes
endometrial decidual degeneration
cervical softening and dialation
release of endogeneou prostaglandins
Tocolytics
uterine relaxants
drugs that relax uterine smooth muscle to inhibit uterine contractions during preterm labor * not used before 20 weeks gestation*
Goal of tocolytic therapy
- inhibit/interrupt uterine contractions and provide increased time inutero for fetal growth and development
- delay delivery in order to allow antenatal steroids to be effects
- allow safe transport of mother ( with baby still inutero)
