Contraindications/Cautions:contraceptives
thrombophlebitis |
thromboembolic
history |
cerebrovascular
disease history (or active) |
bleeding:
unknown cause |
known/possible
breast tumor; other estrogen-dependent cancer |
liver
disease |
asthma |
migraine |
eczema |
hypertension |
optic
neuritis |
diabetes |
retrobulbar
neuritis |
epilepsy |
edema
(e.g. CHF patients) |
adolescents,
before epiphysial closure |
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- drug interactions with antibiotics:
- antibiotics may decrease
contraceptive efficacy (associated with a
decrease in enterohepatic cycling
secondary to decrease in gastrointestinal
flora)
- enterohepatic cycling increases
estrogen bioavailability
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- Postcoital
Contraceptives:
- "morning-after"
pill: estrogen only or estrogen +
progestins
- typically, treatment within
three days (72 hours): 99%
effective
- used often come currently
with antiemetics (40% incidence of
nausea/vomiting)
- Adverse Effects:
- nausea/vomiting
- headache
- dizziness
- breast tenderness
- leg/abdominal
cramps
- Mifepristone
(RU-486)
- progesterone & glucocorticoid
receptor antagonist
- luteolytic action
- effective
postcoital contraceptive in
combination with prostaglandin
- Beneficial Effects: Oral
Contraceptives:
- reduction
in risk of:
- ovarian cysts
- ovarian
cancer
- endometrial cancer
- benign
breast disease
- decreased
incidence:
- pelvic
inflammatory disease
- ectopic
pregnancy
- iron
deficiency
- duodenal
ulcer
- rheumatoid arthritis
- Improvement
in Conditions:
- premenstrual symptoms
- endometriosis
- acne
- hirsuitismin
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Estrogen/Progesterone Inhibitors &
Antagonists
- Tamoxifen
- Competitive partial agonist
inhibitor of estradiol at estrogen
receptors
- nonsteroidal; orally
active
- Adverse/Side
effects:
- hot flushes,
nausea/vomiting (frequency = 25%)
- Tamoxifen: in
adjuvant therapy for breast
cancer: (35% decrease in
contralateral breast cancer
frequency)
- No improvement in
outcome associated with treatment
> 5 years
- Tamoxifen (due to
agonist properties) stimulates
the endometrium; increasing
endometrial cancer risk
- Raloxifene does
not appear to stimulate the
endometrial
- Used in treating breast cancer--NCI Guidelines (4/1999)
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- Stage
I Breast
Cancer
- Following Surgery:
Adjuvant therapy
- For suitable
estrogen-receptor negative
(ER)-negative patients, adjuvant
chemotherapy with a proven
effective regimen.
- There
is continuing controversy
concerning the routine
use of adjuvant
chemotherapy in all
patients with
ER-negative,
node-negative cancers.
- For
ER-positive patients, adjuvant
chemotherapy or tamoxifen (20 milligrams daily).
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- Clomiphene:
- partial agonist; weak
estrogen
- competitive inhibition:
endogenous estrogens
- ovulation-inducing drug
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- Mifepristone
(RU-486)
- Overview:
- "19-nor
steroid": high affinity for
progesterone receptors
- competitively
inhibits progesterone action at
the receptor
- Luteolytic
properties when administered in
mid-luteal time frame
- long half-life
- effective
emergency postcoital
contraceptive (dosage: 600 mg)
- Possible Clinical Uses:
- endometriosis
- breast cancer
- other neoplasms
(with glucocorticoid/progesterone
receptors)
- Present major use: mefepristone
- early
pregnancy termination (effective
approximately 85% of the time)
- Major Adverse
Effect: prolonged bleeding
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Other
Ovarian Inhibitors
- Anastrozole:
- inhibits aromatase --
required for estrogen synthesis
- effective in
tamoxifen-resistant breast cancer
- FDA approved for this use
- Stage IV Breast Cancer: For patients who relapse
following a period of response or
prolonged stability on initial hormone
therapy, either megestrol acetate, anastrozole, or letrozole can be valuable
palliative treatment.
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- Letrozole/Fadrozole:
- nonsteroidal aromatase
inhibitors
- comparably
effective as tamoxifen
- Stage IV Breast Cancer: For patients who relapse
following a period of response or
prolonged stability on initial hormone
therapy, either megestrol acetate, anastrozole, or letrozole can be valuable palliative
treatment.
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- Ovulation-Inducing
Drugs
- Clomiphene
- Overview:
- partial
estrogen agonist; orally
active
- related to
chlorotrianisene
- slowly
excreted
- Pharmacological Effects:clomiphene
- Mechanism
of Action:
- partial
agonist at estrogen
receptors
- promotes
enhanced gonadotropin
& estrogen secretion
- Effects:clomiphene
- stimulates
ovulation in patients
with amenorrhea/other
ovulatory abnormalities
- unknown
mechanism
- Clinical Uses:clomiphene
- promote
ovulation patients
wishing to become
pregnant
- not useful if abnormality
is due to underlying
ovarian or pituitary
failure
- 80%
of patients with
amenorrhea/anovulatory
abnormalities will
initiate ovulatory
cycling: 50% of these
patients are likely to
become pregnant
- Adverse Effects:clomiphene
- Most
common: hot flushes
- Ovarian
enlargement
- a variety
of other symptoms
probably secondary to
hormonal changes (due to
ovulatory menstrual
cycle)
- Multiple
pregnancy:frequency
= 10%
- Contraindications/Cautions:clomiphene
- considered
dosage reduction in
patients with enlarged
ovaries
- treatment
> one-year: possible
increase risk for
low-grade ovarian cancer
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