Maternity II Pharm Flashcards
Oxytocin
Theraputic Acitions
- Promotes an increase in force, frequency, and duration of uterine contractions.
- Initiates and/or stimulates uterine contractions
- Stimulates milk letdown reflex
Oxytocin
Pharmacokinetics
- Functions similarly to natural oxytocin
- Absorption well absored in the nasal mucosa
- Distribution well distributed in extracellular fluid and small amounts reach fetal circulation
- Metabolism/excretion rapidly metabolized by kidneys and liver
- Half-life 3-9 minutes
Oxytocin
Indications of Use
- Induction of labor- initiate uterine contractions prior to spontaneous onset of labor and/or contractions that will lead to labor and delivery
- Increase effectivness of contractions when inadequate or ineffective uterine contractions during labor
- Postpartum control bleeding and promote involution
- Stimulate of milk letdown relfex in breastfeeding mothers
Oxytocin
Drug Interactions
Oxytocin
Complications/ Side effects of oxytocin
- Anti-diuretic effect (non-electrolyte IV solutions should not be used for infusions, may lead to water intoxicity if they are not used)
- Increased cardiac ouput which may lead to increased blood pressure
- IV bolus may lead to decreased blood pressure & tachycardia
- Increased chance of neonatal hyperbilirubinemia
- Increased risk of abnormally strong or titanic contractions leads to fetal distress as placental perfusion is decreased
- Uterine overstimulation
- Increased change of uterine rupture
- Increased change of placental abruption
- Associated with increased risk of epidural anesthesia and increased risk of cesearan
Oxytocin
Contraindications
- Abnormal fetal like, CPD, or cord presentation
- Prior surgery or trauma to uterus
- Placental abnormalities: ie: complete placental previa or if complete placental abruiption has occured or is suspected
- Non-reassuring FHR; fetal distress; and/or posstive stress test (OCT)
- Active genital herpes
- Over distention of the uterus (more than one fetus/ polyhydramnios)
- Abnormalities of uterus, cervix, pelvis, or vagina that are not compatible with vaginal delivery
- Invasive cervical cancer
Oxytocin
FDA Recommendation
The FDA recommends the use of oxytocin only when medically indicated. It should not bue used for elective induction of labor
Oxytocin
indications for use when initating labor
- Inadequate uterine contractions after PROM
- Post term fetus or IUGR
- Fetus in jeopardy if not delivered ASAP
- Maternal medical problems (Rh incompatibility/isoimmunization; diabetes; or renal disease)
- Preeclampsia/eclampsia and/or HELLP
- Intrauterine fetal demise (“stillbirth”)
- Logistics- hisotry of precipitous labors
Oxytocin
Favorable Indicators
Conditions necessary for successful induction
- A reliable indicator is Bishop’s Pelvic Score the higher the scoure the greater the change of a favorable outcome
- Cervical dilation
- Cervical effacement
- Cervical consistency (firm, medium, or soft)
- Station- related to ishial spines
- Position (posterior vs anterior)
Oxytocin
Nursing interventons/ responsibilities
- 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 change of antidiuretic effect
- Monitor for water intoxication
Ergot Alkaloids
used for
sustained uterine contractions
Names of Ergot Alkaloids
- Methylergonovine (methergine)
- Ergotate (ergonovine)
Methylergonovine
Pharamcokinetics
- Effect uterine and smooth muscle stimulates adrenergic, dopaminergic, and serotonergic receptors which results in:
- Stimulation of uterine contractions
- Constriction of arterioles and veins
Methylergonovine
Drug ineractions
Parenteral sympathomimetics and other ergot alkaloids administered together can result in increased vasomotor action related to hypertension
Methylergonovine
Indiations for use
(post aborition and postpartum period only)
- Increase uterine tone
- Decrease bleeding