Pharm EXAM 3
Oxytocin physiologic and pharmacological effects
-uterine stimulation -milk ejection -water retention
Oxytocin adverse effect
-water retention/intoxication
The nurse is caring for a pregnant patient who has chronic asthma. When administering medications to this patient, the nurse should do what?
Advise the patient that taking asthma medications during pregnancy improves fetal outcomes.
The nurse is caring for a patient with epilepsy who is on anticonvulsant therapy and is also breast-feeding. Which patient teaching instruction should minimize the risk to the baby?
"Avoid drugs that have a long half-life."
Teratogenesis and Stage of Development
Development occurs in 3 stages: Week 2: conception (termination or nothing) Week 3-8: embryonic (gross malformations) (1/10) Week 9-term: Fetal (functions and brain related)
For a drug to be a proven teratogen, which criteria must be met? (Select all that apply.)
-The drug must cause a characteristic set of malformations. -The drug must act only during a specific window of vulnerability. - The incidence of malformations should increase with increasing dosage and duration of drug exposure.
Drugs for menorrhagia (heavy menstruation)
-Tranexamic acid (menorrhagia, trauma) -NSAID -Combination oral contraceptives -levonorgestrel-releasing intrauterine system
A nurse develops a plan of care for a pregnant patient receiving nifedipine [Procardia]. Which outcome should be included?
Delivery is postponed for at least 24 hours.
Which nursing action is the priority for a patient in preterm labor who is receiving magnesium sulfate?
Obtaining deep tendon reflexes
Which statement regarding adverse reactions during pregnancy is false?
One in five children is born with a malformation related to drug use during pregnancy. (LESS THAN 1%)
When evaluating the effects of ergonovine [Ergotrate], the nurse expects which assessment finding?
Decreased vaginal bleeding
A nurse is educating a breast-feeding patient about her medications. Which statements by the nurse are true? (Select all that apply.)
-"Drugs taken by lactating women can be excreted in breast milk." - "If drug concentrations in milk are high enough, a pharmacologic effect can occur in the infant." -" "Most drugs can be detected in milk, but concentrations are usually too low to cause harm."
Carboprost tromethamine (Hemabate) -uterine stimulant oxytocics
-#1 agent for postpartum hemorrhage -causes intesnse uterine contractions Adverse: -GI reactions -vomiting and diarrhea -fever -vasoconstriction -constriction of the bronchi
When a pregnant woman has been exposed to a known teratogen, what is the first step in identifying risks for malformation? (Select all that apply.)
-Determine exactly when the drug was taken. -Determine exactly when the pregnancy began.
Ergot alkaloids: ergonovine and methylergonovine - oxytocics for postpartum hemorrhage
-Dried preparation of Claviceps purpurea -Stimulate adrenergic, dopaminergic, and serotonergic receptors -Not used to induce labor (sustained contractions) -Can cause constriction of arterioles and veins and risk of severe hypertension -Used to control postpartum bleeding -SUSTAINED uterine contraction Therapeutic uses: -postpartum bleeding not responding to oxytocin -migraine Adverse effects (IV) -hypertension
Drug therapy during breast-feeding
-Drugs are excreted in breast milk, effect infant Decrease risk to infant -take drugs immediately after breast-feeding -avoid drugs that have a half-life -choose drugs that are excluded from milk -avoid drugs known to be hazardous
Prostagladins (cervical ripening)
-INCREASE COLLAGENASE in cervix, induce labor Side effects: fever, GI, prolonged uterine contraction
Oxytocin (Pitocin) (#1)
-INDUCTION AND POSTPARTUM HEMORRHAGE -naturally produced from posterior pituitary -procuded with orgasm (causes happiness) -milk ejection reflex -similar to antidiuretic hormone (ADH) renal rention
Ergot alkaloids
-POSTPARTUM HEMORRHAGE ONLY -from mold that grows on rye -many side effects (hypertension)
Uterine stimulants (oxytocics) for cervical ripening
-Prostaglandins -Dinoprostone -Misoprostol
Prostaglandins
-RIPEN CERVIX, MAY INDUCE LABOR, POSTPARTUM HEMORRHAGE, ABORTION -naturally produced -cause smooth muscle activity esp in GI tract
Hazards of preterm birth
-before 37 weeks gestation -leading cause of infant/neonatal morbidity -USA: 12.5% of all live births, increasing -Premature birth = 75% of neonatal mortalities, 50% congenital neurological defects Most common: neonatal respiratory distress syndrome, brain hemorrhage, infarcts of intestines
Postpartum hemorrhage
-bleeding after birth, hemodynamic instability -2nd most common cause of maternal death -most common cause: uterine atony (80%) -other causes: lacerations, uterine rupture, inversion, bleeding tendency, retention of placenta Drugs: oxytocins, prostaglandins, ergot alkaloids
Magnesium sulfate
-high dose does not delay preterm birth -increase infant mortality -previously used readily -low-dose may reduce risk of cerebral palsy without increasing mortality
Dinoprostone (cervical ripening) (#1)
-most widely used for cervical ripening -shortens duration of labor, reduced dose of oxytocin -decrease need for C-section -induce abortion -gel or insert can be removed
Misoprostol (cervical ripening)
-not approved for cervical ripening -more convenient/less expensive than dinoprostone -higher incidences of uterine contraction
Challenges with drug therapy during pregnancy and breast-feeding
-not much reliable data on toxicity -effects of drugs are changed by changes of metabolism in pregnancy, timing in pregnancy, fetal metabolism, placental and breast transfer to baby -effects may be subtle (neurological) or long term
3 groups of uterine stimulants (oxytocics)
-oxytocin -ergot alkaloids -prostaglandins
Oxytocin (Pitocin)
-peptide hormone produced by posterior pituitary -increase force, frequency, duration of contraction -uterus becomes more responsive to oxytocin though pregnancy (receptors) -facilitates labor, unclear if initiates labor
What does the uterus normally do?
-provides place for implantation once a month -expands to accommodate and nourish fetus -contracts to expel fetus and placenta AT TERM -contracts to stop atrial flow to placental site, stop postpartum hemorrhage
Uterine relaxants (Tocolytics)
-used to delay preterm birth, not stop it -average delay = 48 hours -buy time to treat infections *if used with glucocorticoids, can accelerate lung development, decrease brain hemmorrhage
Oxytocin precautions and contraindications
-uterine rupture may occur -prolonged uterine contraction > 1minute, cuts circulation to placenta, fetal distress -women with active genital herpes
Drugs used during pregnancy
2/3 of pregnant women take at least ONE medication -Treat pregnancy related problems (nausea, constipation, anemia, and preeclampsia) -Chronic disorders (hypertension, diabetes, epilepsy) -Infectious diseases or cancer -Drugs of abuse (alcohol, cocaine, heroin, nicotine)
Pregnancy changes drug processing
3rd trimester: -renal blood flow doubled -renal excretion accelerated -high blood volume dilutes drugs -liver enzymes changed -carrier molecules (proteins) change -tone and mobility of bowel decrease
A nurse assesses the urine output of a patient receiving oxytocin [Pitocin]. Which finding would require immediate follow-up by the nurse?
80 mL in the past 4 hours
The nurse is preparing to give a drug that is not classified according to a Pregnancy Risk Category. What should the nurse do?
Administer the medication, because the nurse knows that it was in use before 1983.
A nurse prepares to administer a newly prescribed medication to a 22-year-old woman. The insert in the medication package states, "Category X." Select the nurse's best action.
Ask the patient, "When was your last menstrual period?"
Which of these findings, if identified in a patient receiving ergonovine [Ergotrate], should a nurse report to a physician immediately?
Hypertension
How are uterine muscle contractions controlled?
Increase smooth muscle contraction: -beta-adrenergic agonists -oxytocin -prostaglandins 4 classes of drugs: decrease availability of phosphorylated light chain myosin -beta-adrenergic antagonists -calcium channel blockers -cyclooxygenase (COX) inhibitors -oxytocin-receptor antagonists
When to increase uterine muscle activity?
Inducing labor -MUST ripen/soften cervix first -MUST have reason to stop pregnancy that outweighs risks of induction -MOST COMMON: prolonged pregnancy (42 weeks) -Stopping postpartum bleeding
During pregnancy:
Placental drug transfer -all drugs cross placenta -some cross easier than others Adverse reactions during pregnancy -can adversely affect mom and fetus **heparin causes osteoporosis **prostaglandins stimulate uterine contractions **certain pain relieves can depress respiration in fetus
Prevention of preterm labor (2 ways)
Progesterone (hydroxyprogesterone) - synthetic hormone for women with one fetus and a histroy of preterm birth Antibiotics - IF the woman has abnormal vaginal flora (bacterial vaginosis) prescribed probiotics
Which action should a nurse take when a pregnant patient develops uterine contractions after receiving dinoprostone [Cervidil] into the vaginal system?
Remove the insert using the long tape.
Inducing labor
Risk: -prematurity -uterine rupture -infection -need for cesarean birth -fetal damage/distress (brain damage) -water intoxication -death -CONTINUOUS MATERNAL AND FETAL MONITORING IF OXYTOCICS ARE USED
Teratogen risks and exposures
Risks of teratogenesis -avoid unnecessary drug use (cocaine) -consider timing, dose, exposure, alternative drugs -50% of pregnancies are unintended Responding to teratogen exposure -identifying details of exposure -ultrasound scans -counseling (termination, preparation)
A teratogenic drug, such as methotrexate, is most likely to cause learning deficits during which phase of fetal development?
Second and third trimesters
A patient who is near term gestation is receiving oxytocin [Pitocin]. Which response should the nurse expect if the medication is having the desired therapeutic effect?
Stimulation of uterine smooth muscle
Teratogenesis
TO PRODUCE A MONSTER Birth defects -gross (obvious) malformations - ex:cleft palate -neurobehavioral and metabolic anomalies Less than 1% of birth defects caused by drugs Identification of teratogens is difficult *only a few drugs are considered proven teratogens
Terbutaline (Brethine)
UTERINE RELAXANTS (TOCOLYTICS) -Beta2-selective adrenergic agonist -not approved by FDA for this use -cause tachycardia, pulmonary edema, decreased BP, hyperglycemia -fast acting, used to stop contractions in distress -oral or SC only, NOT IV
Indomethacin (Indocin)
UTERINE RELAXANTS (TOCOLYTICS) -NSAID, COX inhibitor, antiprostaglandin -second-line tocolytic -higher risk for neonatal complications Side effects: -prolonged renal insufficiency -bronchopulmonary dysplasia -necrotizing enterocolitis -periventricular leukomalacia (poor brain circulation)
Nifedipine (Procardia, Adalat, Nifedical)
UTERINE RELAXANTS (TOCOLYTICS) -calcium channel blocker -suppress labor up to 48 hours -safer than terbutaline, same efficiency -decreases BP, uterine blood flow
Nitroglycerin (nitric oxide donor)
UTERINE RELAXANTS (TOCOLYTICS) -not used in the USA
Atosiban
UTERINE RELAXANTS (TOCOLYTICS) an inhibitor of the hormones oxytocin and vasopressin
3 categories of drugs that affect uterine function:
UTERINE RELAXANTS (tocolytics) -Uterine relaxation (stop prolonged contraction) -Prevention/suppression of preterm labor UTERINE STIMULANTS (oxytocics) -uterine contraction -induction/augmentation of labor -control of postpartum bleeding -induction of abortion DECREASE MENORRHAGIA (heavy menstrual bleeding)
Which finding in a patient receiving an oxytocin [Pitocin] infusion should be reported to the physician immediately?
Uterine contractions lasting longer than 1 minute
According to the FDA Pregnancy Risk categories, which category represents the greatest risk for fetal harm?
X
Category X
drugs that pose the highest risk of fetal harm and are contraindicated during pregnancy