Nursing Pharmacology Chapter 31: Endocrine: Gonadal Hormones
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 |
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
Contraception: Progestin monotherapy
High incidence of abnormal bleeding
Decreases with time
Amenorrhea is common
Contraceptive Effectiveness: similar to IUD/combination formulations containing 20-30 ug ethinyl estradiol
Depot medroxyprogesterone acetate (DMPA)/three months provides extended inhibition of ovulation
Suppression of ovulation may persist for over year in a half following
Treatment discontinuation (after final injection)
Long-term DMPA
Decreases as for blood loss
Decreases endometrial cancer risk
Progestin implants (subcutaneous) -- L-Norgestrel
Extremely effective
Duration of effect: 5-6 years
Capsules: release between 33% and 50% as much steroid as world contraceptive patients
Low hormone levels resulted in:
Little effect on lipoproteins metabolism
Limited effect on carbohydrate metabolism
Limited effect on BP
Disadvantages:
Requirement of surgical of insertion/removal
Irregular bleeding
Advantages: progestin contraception-- patients with:
Hepatic disease
Hypertension
Psychoses/mental retardation
History of thromboembolic disease
Side Effects:
Dizziness, headache, loathing, weight gain, decreased glucose tolerance
"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 and 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
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)--check current NCI Guidelines
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).
Stage II: Breast Cancer
Following Surgery: Adjuvant Therapy
Following the treatment used to control local disease, adjuvant combination chemotherapy is given to reduce the rate of recurrence and improve survival in pre- and postmenopausal node-positive patients.
Many different drug regimens have been developed.
Numerous studies have shown that combination chemotherapy is superior to single-agent treatment, and single-agent adjuvant chemotherapy should be avoided outside a clinical trial.
The drug combinations listed have been tested and provide therapeutic benefit.
Not all have been compared to an untreated control group in prospective randomized trials.
CMF: cyclophosphamide + methotrexate + fluorouracil.
Various recognized combinations of cyclophosphamide , doxorubicin, fluorouracil
CA +/- tamoxifen: cyclophosphamide + doxorubicin +/- tamoxifen
Following the treatment used to control local disease, adjuvant endocrine therapy with tamoxifen alone is given to reduce the rate of recurrence and improve survival in postmenopausal patients with lymph node involvement and positive hormone receptors.
Tamoxifen, either alone or combined with chemotherapy, prolongs disease-free survival when administered for 24 months as adjuvant therapy to postmenopausal women with axillary lymph node metastases.
In a large trial of 3887 postmenopausal women with node-positive and node-negative breast cancer randomized to receive either 2 or 5 years of adjuvant tamoxifen, the longer duration of tamoxifen appeared to improve disease-free and overall survival.
For ER-negative patients or ER-positive patients with large tumors, adjuvant chemotherapy with a proven effective regimen.
For ER-positive patients, adjuvant chemotherapy or tamoxifen (20 mg/day)
Data from the NSABP-B-16 protocol indicate that patients 50 years of age and older who have hormonally responsive, node-positive tumors treated with chemotherapy (AC) and tamoxifen had a significantly increased disease-free and overall survival when compared with patients given tamoxifen alone.
There was no apparent drug interaction between chemotherapy and tamoxifen.
Stage IIIB Breast Cancer(locally advanced, including inflammatory)
see: NIH/NCI website for most current NCI recommendations
In stage IIIB breast cancer, initial surgery is generally limited to biopsy.
Removal of residual tumor may be performed if a good response is achieved with chemotherapy with or without radiation therapy.
Treatment options: Standard:
1. Core needle biopsy, fine-needle aspiration or incisional biopsy for diagnosis and receptor protein assay followed by preoperative chemotherapy.
If the patient has a good response, local therapy with surgery and/or irradiation is recommended. If the response is poor, palliative radiation therapy may be recommended.
Chemotherapy regimens with or without hormones are given in conjunction with the above surgical and radiotherapeutic procedures. Chemotherapy can be given prior to surgery in cases where primary resection is not feasible or is technically difficult.
Commonly used chemotherapy regimens include:
CMF: cyclophosphamide + methotrexate + fluorouracil.
CAF: cyclophosphamide + doxorubicin + fluorouracil .
CA: cyclophosphamide + doxorubicin.
3. If combination chemotherapy is contraindicated, pretreatment with tamoxifen may be recommended for patients whose tumors are positive for estrogen- and progesterone-receptor proteins.
Stage IV Breast Cancer
see: NIH/NCI website for most current NCI recommendation for most current NCI recommendations
Treatment Options Standard:
A biopsy to determine histology and ER and PR levels.
If visceral disease is minimal or absent and ER and PR status is positive, hormonal therapy is an excellent first treatment.
Tamoxifen or oophorectomy can be used for premenopausal patients.
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.
Megestrol is associated with weight gain, which may be an undesirable side effect.
If visceral disease is present or ER and PR status is negative, one of the following combination chemotherapy regimens will produce equivalent results:
CMF: cyclophosphamide + methotrexate + fluorouracil.
CAF: cyclophosphamide + doxorubicin + fluorouracil.
CA: cyclophosphamide + doxorubicin.
Partial agonist; weak estrogen
Competitive inhibition: endogenous estrogens
Ovulation-inducing drug
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
Overview:
Isoxazole derivative of ethisterone
Suppresses ovarian function
Slowly metabolize; half-life > or 15 hours
Mechanism of Action:
Inhibits midcycle LH/FSH surge
Does not affect basal LH/FSH levels
Binds to many receptor types/proteins including:
Androgen
Progesterone
Glucocorticoid
Sex hormone-binding globulin
Corticosteroid-binding globulin
Inhibit several cytochrome P450 systems, including:
P450scc -- cholesterol side chain-cleaving form
P450c11 -- 11-β-hydroxylase
P450C17 -- 17-α-hydroxylase
P450c21 -- 21-hydroxylase
Primary use: treating endometriosis
Other uses:
Breast fibrocystic disease
Hematologic
Christmas disease
Idiopathic thrombocytopenic purpura
Hemophilia
Weight gain, edema, reduced breast size, acne, voice deepening, headache, hot flushes, libido changes, muscle cramps, increased hair growth
In presence of hepatic dysfunction (danazol may cause some mild/moderate hepatocellular damage)
Contraindications: Danazol: may cause urogenital anomalies in the newborn
In pregnancy
Breast feeding
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.
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.
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 and estrogen secretion
Effects: clomiphene
Stimulates ovulation in patients with amenorrhea/other ovulatory abnormalities
Unknown mechanism
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
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
Primary Reference: Goldfien, A., The Gonadal Hormones and Inhibitors, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 653-680.
Carr, B. R. and Bradshaw, K.D, Disorders of the Ovary and Female Reproductive Tract , In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, pp 2097-2115.
Mitchell-Leef, D.E. Endometriosis in Medicine for the Practicing Physician, Fourth edition, (Hurst, J. Willis, editor in chief) Appleton and Lange, 1996, pp 751-755.