OB Pharmacology Flashcards
OB Pharm
Tocolytics
Slow contractions
○ Terbutaline
○ Magnesium-sulfate
Oxytotics
Stimulate contractions
○ Oxytocin
Terbutaline
Therapeutic class: Selective Beta 2 adrenergic agonist
Mechanism of action: Binds to beta 2 adrenergic receptors in the respiratory system to cause
bronchodilation by inhibiting the release of hypersensitivity reaction products from mast cells.
ALSO works on beta 2 receptors in the uterus to slow or stop contractions.
* OB Indications
* Preterm labor
Nursing considerations:
* SE: shakiness, jitteriness, dizziness, drowsiness, sleep disturbances, weakness, headache,
nausea, vomiting, tachycardia, hypertension, hyperglycemia, CNS overstimulation
* Assess HR, BP, EKG, blood glucose
* Monitor HR of mom and baby when used in labor - monitor fetal heart monitor strips
closely
* Monitor EKG
Magnesium sulfate
Therapeutic class: Electrolyte
Indication: Hypomagnesemia, Torsade de Pointes, pre-eclampsia, preterm labor,
seizures, asthma exacerbation
Nursing Considerations:
● Monitor for hypermagnesemia
○ Confusion, dizziness, weakness, decreased reflexes
● Give IV slowly
Oxytocin
Therapeutic class: Hormones
Indication: Induction of labor; PPH
Action: Stimulates uterine smooth muscle causing it to contract
Nursing Considerations:
● Monitor contractions
● Monitor fetus
● Warn mother contractions will be more painful
● Monitor BP, HR, glucose, and K
Prostaglandins
● Ripen the cervix
○ Prostaglandin E1 (Misoprostol)
○ Prostaglandin E2 (Dinoprostone)
Misoprostol
Therapeutic class: Prostaglandin E1 analogue
Indication: Stomach ulcers, induction of labor, elective pregnancy termination, D&C
Action: Inhibits acid secretion through stimulation of the prostaglandin E1 receptors in
the stomach. It also causes the cervix to soften and the uterus to contract.
Nursing considerations:
● Closely monitor uterine contraction and the FHR in response to the contractions
● Can be given SL or vaginally
● Use with caution in women who have had a prior uterine surgery, as it can
increase the risk of uterine rupture
Dinoprostone
Therapeutic class: Prostaglandin E2 analogue
Indication: Induction of labor, elective termination of pregnancy
Action: Stimulates the muscles in the uterus to contract and also causes cervical
dilation
Nursing considerations:
● Closely monitor uterine contractions and the FHR in response to the contractions
● It can be given as a vaginal gel or a vaginal suppository
● It can very slightly increase the risk for amniotic fluid embolism
Labor Pain Control Methods
Natural methods
● Hypnobirthing
● Hydrotherapy
● Touch therapy
● Movement
● Positioning
● Breathing
Nitrous Oxide
● First made popular in Europe and Australia, this method is becoming more
common throughout U.S. hospitals as a minimally invasive tool to manage
labor pain.
● A tasteless and odorless gas that is mixed with oxygen through a mask
● The mother will hold the mask and decide when to take a breath – this
typically is most effective if the mother begins to inhale about 30 seconds
before the onset of a contraction
● It helps to reduce anxiety and causes a feeling of well-being
● It does not limit movement for the client, slow labor, or cause significant risk
for the baby
Systemic Analgesics
● Lessens the pain without a loss of feeling or muscle movement
● Typically, the medications used are opioids given through the IV
● Typical narcotics given in labor include:
○ Meperidine (Demerol), Butorphanol (Stadol), Morphine and Nalbuphine (Nubain)
● These typically “take the edge off”, but the bulk of the pain will remain
● These do cross the placenta, so limited use is better, as it can lead to
respiratory depression in both the mother and baby. However, with
regulated use, APGAR scores are generally not or minimally impacted.
● Some hospitals limit use an hour prior to expected delivery to lessen
sedation in the newborn. This can impact breathing and the first
breastfeeding attempts.
Local Anesthetics
Local Anesthetics
● This method is often used if an incision needs to be made to make the
vaginal opening bigger (episiotomy) or to repair a laceration/tear that
occured during delivery
● It will very quickly numb a specific area and negative effects to the mother or
baby are rare
● This will do nothing to relieve the pain from contractions, so typically women
use this in addition to other forms of pain control
Regional Anesthesia – Epidural
● Small catheters are placed into the lower spine that slowly pump pain
medication to that area. This will stop pain signals from traveling from your
spine to the brain.
● This method removes the most pain without slowing labor too much. The mother is awake and alert and should still be able to feel pressure/contractions to know when to push.
● They don’t always work–some women report no or partial pain relief if the catheter wasn’t placed correctly.
● They can drop blood pressure quickly–monitor closely!
● Many women with an epidural cannot walk or move their lower
extremities–sometimes a catheter is placed in the bladder in this case.
headache - epidural blood patch, but first nsaids, caffeine
Regional Anesthesia – Spinal Block
● Typically used for pain control during a planned C-section.
● This medication is injected directly into the fluid of the spinal cord and will
block pain for a couple of hours. It takes effect very quickly, so it also may be
given if a painful procedure is needed during a vaginal delivery (vacuum
assist).
● It will completely remove any pain from the lower body for 1-2 hours
● It may decrease blood pressure, so monitor closely. In rare cases, this will
also lead to a drop in fetal HR.
General Anesthesia
● This is reserved for use only during emergency situations
● It may also rarely be used if a spinal/epidural won’t work (history of spinal
injury)
● This causes complete loss of sensation and consciousness
● It will delay how quickly the mother can bond with her new baby and often
impacts breastfeeding negatively
● Risks of this method include:
○ Inability to place the ETT, increased risk for pneumonia/lung infections
○ Anesthetic medication toxicity
○ Respiratory depression in the newborn
○ Fetal lethargy
○ Longer hospital stays and recovery times
