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
Methylergonovine
Adverse side-effects
- Severe Hypertension
- bradycardia
- Nausea and vomiting
- Seizures and gangrene with overdose
Mytherlergonovine
Contraindications
- Not to be given before delivery of the placenta
- Not to be given if uterine sepsis
- Not to be given for threatened spontanseous aborption
- Don’t gie if preeclampsia/eclampsia
Mytherlergonovine
Nursing implications/considerations
- Caution if history of cardiovascular, renal, or hepatic dysfunction
- Due to adverse effects usually reserverd for use with severe or life threating uterine bleeding
- Monitor vital signs and uterine response during and after parental administration until patient stabilized (usually 1-2 hours)
Prostaglandins
What are they
Hormones which are synthesized in all body tissues
Prostoglandins
Clinical use
Limited clinical use usually is given in conjunction with oxytocin
Prostaglandins
Theraputic actions
- Induce abortion
- Evacuate uterus with missed aborition, bening hydatidiform mole, or intrauterine fetal death up the 28 weeks gestation
- Induce cervical ripening
- Control postpartum hemorrhage
- Stimulates myometrium (ie: smooth muscle layer of uterus) to contract leads to homostatsis at placental attachment site
Prostaglandins
Pharacokinetics
mechanism of action is not fully determined
Postoglandins
Drug interactions
increases action of oxytoic drugs
Prostaglandins
Contraindicated for patients with:
Prostaglandins
Adverse side effects
Prostaglandins
Nursing Implications
- Administered intravaginally after warm to room temperature
- Carefully monitor uterine activity and fetal status (hypertonic contractions and fetal distress)
Prostoglandins
Most Commonly Used
- Dinoprotone (cervidil, Prepidil Gel)
- Misoprostol (cytotec) - (cervical ripening is unlabeled use) *oxytocin may be started 1 hour after 1st dose [decreased gastric acid secretion and protects GI mucosa (most commonly used for NSAID induced ulcers)]
- Carboprost tramethamine (hemabate): dose 250 mcg IM, induce pharamcologic abortion between 13 and 20 weeks, Control post partum bleeding, common side effects vomiting and diarrhea
Progesterone Receptor Antagonist
Mifepristone
RU-486
- medical termination of pregnacies up to 49 days gestation
- Softening and dilation of the cervix prior to mechanical cervical dilation for pregnancy temination
- Labor induction when fetal death inutero
- Prevents ovulation when taken daily (2mg/day)
- 10mg given prior to ovulation delays ovulation by 3-4 days
Mifepristone
Side effects
nearly all women exerpience abdominal pain uterine cramping and vaginal bleeding or spotting for an average 9-16 days
In medical abortion blockages of progesterone receptors directl causes
- endometrial decidual degernation
- Cervical softening and dilation
- Release of endogenous prostaglandins
