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42 Cards in this Set
- Front
- Back
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What is the basic function of oxytocics? What are the three major classes of these drugs?
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To stimulate uterine contractions.
- Oxytocin - Prostaglandins - Ergot Alkaloids |
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What is the basic function of tocolytics? What are the three (five) major classes of these drugs?
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To inhibit uterine contractions and to inhibit premature labor (< 36 weeks) to permit further fetal development.
- β2 agonists - CCBs - NSAIDS (- Magnesium sulfate, not used) (- Oxytocin receptor antagonists, not used in the US) |
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c/c contractures vs. contractions in the context of labor
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Contractures: long-lasting, low-frequency
Contractions: frequent, high-intensity activity |
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Partuition: give a basic outline of the three phases
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Phase I: contractions of increasing strength, cervix dilates
Phase II: ~1 hour, expulsion of fetus Phase III: ~10 minutes, expulsion of placenta, aftercontractions of the uterus (reduces bleeding). |
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Explain the relationship between oxytocin and vasopressin
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Oxytocin and vasopressin are very similar
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Oxytocin: what does it do?
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- Stimulates uterine smooth muscle contraction
- Uterine has to be "primed" with estrogen in order to be sensitive to oxytocin. - Oxytocin also stimulates breast myoepithelial cells for lactation. |
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Oxytocin: uses
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- To induce labor (IV)
- To contract uterus after birth to reduce bleeding (IM) - To promote milk release (intranasal) |
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What aspects to you need to monitor when you induce labor?
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- Fetal and maternal HR
- Maternal BP - Frequency of contractions |
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Oxytocin: AE
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- Tetany of uterus
- Oxytocin acts like ADH, so can retain water and can dilute serum Na, leading to hyponatremia. (also may cause HF, seizures, death) - Preservative used with oxytocin (chlorobutanol) may have a negative inotropic effect and cause vasodilation, hypotension, and tachycardia. |
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Dinoprostone
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Prostaglandin (PGE2)
Used for cervical ripening to prep for labor Used to produce midtrimester abortion Used as a vaginal gel or suppository |
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Carboprost
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Prostaglandin (15-methyl PGF2)
Used to produce midtrimester abortion Used to decrease pospartum bleeding IM |
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Prostaglandins: AE
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IV:
- Vomiting, fever, diarrhea, bronchoconstriction - Hypo/hypertension, syncope, dizziness, flushing IM carboprost and local administration of dinoprostone limit systemic AEs. |
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Misoprostol: uses, AE, off-label uses.
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PGE1 analog used to prevent NSAID ulcers.
- Used 48 hours after Mifepristone (RU486) - AE: vomiting, diarrhea, abdominal, pelvic pain. Vaginal bleeding common. - Off-label use: cervical ripening, labor induction. |
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Mifepristone (RU-486)
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A progestin receptor partial agonist.
Used to produce first trimester abortion by destroying the placenta. |
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Ergot Alkaloids
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Derived from fungus that grows on rye, etc.
Molecular activities: agonists/antagonists at the serotonin receptor (5-HT), dopamine & α-adrenergic receptors. Produces strong uterine contractions: - low doses: clonic contractions - high doses: tonic contractions Too dangerous for use during labor |
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Name 2 ergot alkaloids
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Ergonovine
Methylergonovine |
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Ergonovine, Methylergonovine
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Ergot alkaline
Used to decrease bleeding post partum or after abortion AE: NVD, vasospasm, bowel ischemia |
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Ritodrine
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(Yutopar) only FDA approved drug for preterm labor
Only available IV in the US (available as PO in Canada) |
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What are some drugs that are used off label as tocolytics?
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Albuterol, terbutaline
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β2-agonists as tocolytics: AE
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Increased maternal and fetal HR
Arrhythmias Hypokalemia Maternal pulmonary edema Myocardial ischemia Skeletal muscle tremor Hyperglycemia Does not decrease fetal mortality! |
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What CCBs can be used as tocolytics?
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Nifedipine, but not approved for use in the US
- As effective as ritodrine but fewer maternal AE and lower neonatal morbidity. - AE: Dizziness, nervousness Flusing, headache, nausea Muscle cramps, tremors Hypotension Decreased fetal blood supply |
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How can NSAIDs function as tocolytics?
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NSAIDs inhibit uterine contractions, prolonging gestation
AE: closure of ductus arteriosus |
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Atosiban
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Synthetic oxytocin receptor antagonist.
Specific for uterine smooth muscle IV, not available in the US (is in Canada) AE: NV, headache, dizziness, flushing, tachycardia, hypotension, hyperglycemia. |
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What are some basic stragegies for treating urinary incontinence?
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- Give a α1-agonist (psuedoephedrine)
- Estrogens? - Tricyclic antidepressants (Na channel blockers ?) - Exercise, surgery, implants |
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What is the main symptom of urge incontinence?
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Sudden involuntary bladder contraction.
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What types of drugs are used to treat urge urinary incontinence?
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Muscarinic antagonists/ antispasmodics (Oxybutynin, Tolterodine)
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Oxybutynin
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Antimuscarinic/antispasmodic used to treat urge urinary incontinence.
Comes in transdermal patch and sustained release form which may reduce systemic AEs. (Ditropan) |
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Oxybutynin, tolterodine: AE
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Systemic antimuscarinic effects
Dry mouth, blurred vision, dizziness, constipation, urinary retention, sedation. Many cannot tolerate and use adult diapers instead. |
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Tolterodine
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Antimuscarinic used for urge urinary incontinence
Claims to be more bladder selective (only slightly so) Less dry mouth (Detrol) |
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How do α1-antagonists decrease urinary retention?
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They antagonize sympathetic tone to the bladder sphincter. Relax the sphincter = less outflow resistance.
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Doxazosin
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α1-antagonist used to treat urinary incontinence. Blocks sympathetic tone to bladder sphincter.
AE: orthostatic hypotension, dizziness, fatigue. (Cardura) |
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Tamsulosin
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α1-antagonist used to treat urinary incontinence. Blocks sympathetic tone to bladder sphincter.
AE: dizziness, fatigue. Tamsulosin generally has less orthostatic hypotension. (Flomax) |
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Name a 5 α-reductase inhibitor
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Finasteride (Proscar)
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5 α-reductase inhibitors: what do they do?
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Inhibit the conversion of testosterone to DHT.
This decreases the size of the prostate, decreases outflow resistance, and decreases urinary retention. Takes months to work! Also promotes hair growth! α1-antagonists can have faster action. |
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Finasteride
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5 α-reductase inhibitor
Can decrease the incidence of prostate cancer. Often used in combination with an α1-antagonist AE: Impotence Decreased libido Decreased ejaculate volume Gynecomastia Pregnant women should not handle tablets! There is a risk to male fetal development. |
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Alprostadil
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PGE1 used for erectile dysfunction
Intravacernosal injection or urethral suppository. Relaxes trabecular smooth muscle and dilation of cavernosal arteries. For patients with spinal cord injuries or prostatectomies May be used in a "trimix" alprostadil + papaverine (nonspecific muscle relaxant) + phentoamine AE: pain at injection site, priapism |
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What are cGMP phosphodiesterase type 5 inhibitors used for?
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Erectile dysfunction
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What is the MOA of cGMP phosphodiesterase type 5 inhibitors?
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sexual arousal --> NO release --> activation of guanylyl cyclase --> increased cGMP --> vasodilation --> engorgement
PDE5 inhibitors inhibit the breakdown of cGMP |
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Name three cGMP phosphodiesterase type 5 inhibitors.
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Sildenafil (Viagra) 4 hours
Tadalafil (Cialis) 36 hours Vardenafil (Levitra) 4 hours Differences in selectivity and half-life. |
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cGMP phosphodiesterase type 5 inhibitors: AE
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Used for erectile dysfunction
Headace Flushing Dyspepsia Abnormal vision, blindness, hearing loss Back pain with tadalafil! |
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Tadalafil: special AE
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Back pain!
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cGMP phosphodiesterase type 5 inhibitors: contraindications
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Pts taking organic nitrates and α1-antagonists, antiHTNs --> hypotension!
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