Term
| what happens to the myometrium during pregnancy? |
|
Definition
| undergoes extensive hypertrophy |
|
|
Term
| what types of receptors are on myometrial cells? |
|
Definition
| excitatory and inhibitory |
|
|
Term
| 3 excitatory receptors on myometrial cells? |
|
Definition
1. alpha1 adrenergic
2. oxytocin
3. prostaglandin |
|
|
Term
| what are the inhibitory receptors on myometrial cells? |
|
Definition
|
|
Term
| how is labor initiated in humans? |
|
Definition
| elevated cortisol + depressed progesterone |
|
|
Term
| how is the uterus primed for initiation of labor in humans? |
|
Definition
mediated by hormones
increase the density of oxytocin receptors and PGE |
|
|
Term
| what is the goal of initiation of labor/priming the uterus? |
|
Definition
| increase the frequency and organization of contractions |
|
|
Term
| how do receptors on the myometrium inhibit contration? |
|
Definition
| B adrenergic agonists --> increase cAMP --> inhibit contraction |
|
|
Term
| how do receptors on the myometrium cause contration? |
|
Definition
| they are coupled to PLC --> IP3 --> increase Ca --> contraction |
|
|
Term
| 4 uses of drugs that stimulate the uterus? |
|
Definition
1. induction of labor
2. control of postpartum atony and hemorrhage
3. induction of uterine contractions after C section or uterine surgery
4. therapeutic abortion in first trimester |
|
|
Term
| what drug is used to induce labor? |
|
Definition
|
|
Term
| 3 drugs used to control postpartum atony and hemorrhage? |
|
Definition
1. oxytocin
2. ergonovine
3. misoprostol |
|
|
Term
| what drug is used for induction of uterine contractions after C section or uterine surgery? |
|
Definition
|
|
Term
| 2 drugs used for therapeutic abortion? |
|
Definition
1. prostaglandin
2. mifepristone |
|
|
Term
oxytocin is secreted from where?
what other hormone is secreted from the same organ?
where are these hormones made? |
|
Definition
posterior pituitary
vasopressin/ADH
made in hypothalamus |
|
|
Term
| what are conditions in which the induction of labor may be indicated (11)? |
|
Definition
1. prolonged pregnancy
2. preeclampsia
3. chronic HTN
4. diabetes mellitus
5. Rh isoimmunization
6. previous stillbirth
7. advanced maternal age
8. intrauterine death
9. intrauterine growth retardation
10. major fetal anomalies
11. hydramnios |
|
|
Term
| administration of oxytocin? |
|
Definition
| infused IV because it is a peptide and not orally active |
|
|
Term
|
Definition
|
|
Term
| mechanism of action of oxytocin? |
|
Definition
| binds to receptors on myometrium - increases electrical activity |
|
|
Term
|
Definition
| increases strength and organization of contractions |
|
|
Term
| when is the uterus very responsive to oxytocin and why? |
|
Definition
in late gestation
because the receptors have increased |
|
|
Term
| what is important about administering oxytocin and why? |
|
Definition
IV must be started slowly until see increase in contractile strength
because responses are variable even though the uterus is very responsive in late gestation |
|
|
Term
| contraindications for oxytocin? |
|
Definition
1. previous uterine surgery
2. abnormal fetal position
3. evidence of fetal distress |
|
|
Term
| side effects of oxytocin? |
|
Definition
rare
1. nausea
2. fetal trauma
3. uterine rupture
4. water intoxication |
|
|
Term
| why is water intoxication a side effect of oxytocin? |
|
Definition
| because of it's ADH-like activity |
|
|
Term
| can induction of labor be elective? |
|
Definition
| NO not without medical indications |
|
|
Term
| chemical nature of oxytocin? |
|
Definition
| physiological substance; peptide |
|
|
Term
| nature of uterine contraction with oxytocin? |
|
Definition
| contraction followed by relaxation |
|
|
Term
| sensitivity of uterus to oxytocin? |
|
Definition
increases with duration of pregnancy
most sensitive at term; immature uterus is resistant |
|
|
Term
| can oxytocin be administered orally? |
|
Definition
|
|
Term
| duration of action of oxytocin? |
|
Definition
|
|
Term
| onset of action of oxytocin? |
|
Definition
IV - immediate
IM - 2.5 mins |
|
|
Term
|
Definition
1. induction of labor
2. postpartum uterine atony |
|
|
Term
|
Definition
rapid
but has prolonged actions |
|
|
Term
| does sensitivity to ergonovine increase at term? |
|
Definition
YES
but can be used before term as well |
|
|
Term
| actions of ergonovine on the uterus? |
|
Definition
alpha-adrenergic and serotoninergic
stimulates contraction |
|
|
Term
| side effects of ergonovine? |
|
Definition
|
|
Term
|
Definition
| prevention of postpartum uterine atony and hemorrhage |
|
|
Term
| chemical nature of ergonovine? |
|
Definition
|
|
Term
| nature of uterine contraction with ergonovine? |
|
Definition
|
|
Term
| sensitivity of uterus with ergonovine? |
|
Definition
increases at term
non-pregnant and immature uterus also stimulated |
|
|
Term
| administration of ergonovine? |
|
Definition
|
|
Term
| onset of action of ergonovine? |
|
Definition
|
|
Term
|
Definition
prolonged
particularly after high dose |
|
|
Term
|
Definition
| prevention of postpartum uterine atony and hemorrhage |
|
|
Term
| what is a PGF2-alpha tocolytic agent? |
|
Definition
|
|
Term
| what is a PGE1 tocolytic agent? |
|
Definition
|
|
Term
|
Definition
| intra-amniotic injection or vaginal suppository |
|
|
Term
| what are prostaglandins used in combo with for termination of first term pregnancy? |
|
Definition
| mifepristone or methotrexate |
|
|
Term
| prostaglandins are used in combo with mifepristone or methotrexate for what? |
|
Definition
| termination of first term pregnancy |
|
|
Term
| what is the direct action of prostaglandins as tocolytics? |
|
Definition
| induce contractions of the uterus |
|
|
Term
| what is a secondary action of prostaglandins? |
|
Definition
| also used to soften the cervix prior to delivery |
|
|
Term
| side effects of prostaglandins? |
|
Definition
1. uterine rupture
2. transient pyrexia
3. nausea
4. diarrhea |
|
|
Term
| why can prostaglandins cause a transient pyrexia? |
|
Definition
| they stimulate receptors in the hypothalamus |
|
|
Term
| chemical nature of prostaglandins? |
|
Definition
physiological substance
fatty acid derivative |
|
|
Term
| nature of uterine contraction with prostaglandins? |
|
Definition
| contraction followed by relaxation |
|
|
Term
| sensitivity of uterus with prostaglandins? |
|
Definition
| contracts uterus in all stages of pregnancy and also non-pregnant and immature uterus |
|
|
Term
| administration of prostaglandins? |
|
Definition
| oral, intra-vaginal, IV, intra-amniotic |
|
|
Term
|
Definition
|
|
Term
|
Definition
1. induction of labor
2. uterine atony
3. hemorrhage |
|
|
Term
| what 2 hormones are secreted by the posterior pituitary? |
|
Definition
1. oxytocin
2. vasopressin/ADH |
|
|
Term
| ADH function in vasculature? |
|
Definition
activates V1 receptors --> Ca increase --> SM contraction --> vasoconstriction
very potent |
|
|
Term
| how does the V1 receptor in the vasculature lead to vasoconstriction? |
|
Definition
| ADH binds --> coupled to PLC --> stimulates IP3 production --> increases Ca |
|
|
Term
| ADH function in the kidney? |
|
Definition
| activates V2 receptors --> coupled to AC --> increase cAMP --> causes water absorption |
|
|
Term
|
Definition
vasculature - V1 receptor leads to vasoconstriction
kidney - V2 receptor leads to water reabsorption |
|
|
Term
| what is a vasopressin V1 receptor selective agonist? |
|
Definition
|
|
Term
| terlipressin is what kind of drug? |
|
Definition
| vasopressin V1 receptor selective agonist |
|
|
Term
| how does terlipressin differ from vasopressin? |
|
Definition
| more selective than vasopressin - only activates V1 |
|
|
Term
|
Definition
1. bleeding
2. esophageal varices
3. hemorrhagic shock |
|
|
Term
| administration of terlipressin? |
|
Definition
| IV or directly to blood vessels |
|
|
Term
| what is a vasopressin V2 receptor selective agonist? |
|
Definition
|
|
Term
| what type of drug is desmopressin? |
|
Definition
| vasopressin V2 receptor selective agonist |
|
|
Term
|
Definition
1. diabetes insipidus
2. bleeding disorders |
|
|
Term
| what is diabetes insipidus? |
|
Definition
| inability to secrete or make normal ADH |
|
|
Term
| how does desmopressin work in diabetes insipidus? |
|
Definition
| mediates water reabsorption through V2 receptor |
|
|
Term
| administration of desmopressin? |
|
Definition
intranasal preparation
enough is absorbed from nasal mucosa to be effective |
|
|
Term
| how is desmopressin used in treatment of bleeding disorders? |
|
Definition
| increases von Willebrand factor |
|
|
Term
| mechanism of action of ethanol as a tocolytic agent? |
|
Definition
1. inhibition of endogenous oxytocin and ADH release
2. depression of myometrium
3. antagonism to prostaglandins |
|
|
Term
| why is ethanol no longer used as a tocolytic agent? |
|
Definition
| because the incidence of fetal distress syndrome is not reduced |
|
|
Term
| use of drugs that inhibit uterine contractions? |
|
Definition
| to delay premature labor and slow or arrest delivery |
|
|
Term
| drugs that inhibit uterine contraction on average work for how long? |
|
Definition
|
|
Term
| why is the window of time that drugs inhibit uterine contraction important? |
|
Definition
| during that time a corticosteroid is given to promote lung surfactant development |
|
|
Term
| many patients respond to what instead of drugs to inhibit uterine contraction? |
|
Definition
|
|
Term
| contraindications for tocolytics? |
|
Definition
1. membranes already ruptured
2. fetal distress |
|
|
Term
| admin of magnesium sulfate? |
|
Definition
|
|
Term
| mechanism of action of magnesium sulfate? |
|
Definition
| divalent cation that blocks Ca effect --> reduces excitability of uterus |
|
|
Term
| magnesium sulfate is administered IV to a final concentration of what? |
|
Definition
|
|
Term
| excretion of magnesium sulfate? |
|
Definition
|
|
Term
| side effects of magnesium sulfate? |
|
Definition
1. resp depression
2. hypotension
3. cardiac arrest |
|
|
Term
| 3 Ca channel blockers used as tocolytic agents? |
|
Definition
1. verapamil
2. nifedipine
3. nicardipine |
|
|
Term
| mechanism of action of Ca channel blockers as tocolytic agents? |
|
Definition
| block Ca entry into myometrial cells |
|
|
Term
| administration of Ca channel blockers? |
|
Definition
|
|
Term
| side effects of Ca channel blockers? |
|
Definition
1. headaches
2. hypotension
3. reflex tachycardia |
|
|
Term
| ritodrine and terbutaline are what type of drug? |
|
Definition
| beta2-adrenergic agonists |
|
|
Term
| administration of ritodrine and terbutaline? |
|
Definition
|
|
Term
| mechanism of ritodrine and terbutaline as tocolytics? |
|
Definition
| stimulate cAMP in myometrium |
|
|
Term
| side effects of ritodrine and terbutaline in the mother? |
|
Definition
1. tachycardia
2. hyperglycemia
3. pulmonary edema |
|
|
Term
| side effects of ritodrine and terbutaline in the fetus? |
|
Definition
1. tachycardia
2. dysrythmias |
|
|
Term
| administration of indomethacin? |
|
Definition
|
|
Term
| administration of COX-2 inhibitors? |
|
Definition
|
|
Term
| mechanism of action of indomethacin or COX-2 inhibitors? |
|
Definition
| inhibit prostaglandin synthesis |
|
|
Term
| indomethacin or COX-2 inhibitors are useful how as tocolytic agents? |
|
Definition
|
|
Term
| side effects of indomethacin or COX-2 inhibitors? |
|
Definition
1. nausea
2. diarrhea
3. allergic rash
4. oligohydramnios |
|
|
Term
|
Definition
| < 300 mL of amniotic fluid at term |
|
|
Term
| what is the biggest risk with use of indomethacin or COX-2 inhibitors? |
|
Definition
premature closure of the ductus arteriosus
prostaglandins normally maintain patency in the fetus |
|
|
Term
| how are synthetic corticosteroids used in tocolytic therapy? |
|
Definition
| to mature surfactant in the lungs |
|
|
Term
| what women are given progesterone or 17 hydroxyprogesterone? |
|
Definition
| women at high risk for premature delivery - those who have miscarried before |
|
|
Term
| is progesterone or 17 hydroxyprogesterone used as a tocolytic agent? |
|
Definition
|
|
Term
| effect of progesterone or 17 hydroxyprogesterone on miscarriage rates? |
|
Definition
| reduces incidence of miscarriage by 30% |
|
|
Term
| when is progesterone or 17 hydroxyprogesterone? |
|
Definition
| starting at 14-16 weeks gestation for women who are at high risk for premature delivery |
|
|
Term
Tocolytic therapy delays labor by an average of:
a. 4 hours
b. 48 hours
c. 2 weeks
d. 2 years |
|
Definition
|
|
Term
Oxytocin is an excellent drug for the induction of labor because:
a. It can be administered orally
b. It also causes cervical ripening
c. The plasma half-life is a few minutes
d. The plasma half-life is a few hours |
|
Definition
| c. The plasma half-life is a few minutes |
|
|
