Chapter 34: Women's Health Drugs
Mechanism of Action for Osteoporosis drugs
Bisphosphonates: alendronate (Fosamax), ibandronate (Boniva), Risedronate (Actonel), Zoledronic acid (Reclast) work by inhibiting osteoclast-mediated bone resorption, thus preventing bone loss Selective Estrogen Receptor Modulators: Raloxifene (Evista), Tamoxifen (Nolvadex) stimulate estrogen receptors on bone and increase bone density Calcitonin: directly inhibits osteoclastic bone resorption (like thyroid hormone) Teriparatide: Only drug that stimulates bone formation, derivative of parathyroid hormone, action similar to natural parathyroid hormone Denosumab: monoclonal antibody that blocks osteoclast activation, thereby preventing bone resoprtion
Contraindication of Osteoporosis Drugs
Bisphosphonates: drug allergy, hypocalcemia, esophageal dysfunction, inability to sit or stand upright for at least 30 mins after taking medication Selective Estrogen Receptor Modulators: women w/known drug allergy to these drugs, women who are or may become pregnant, women w/venous thromboembolic disorder (deep vein thrombosis, pulmonary embolism, retinal vein thrombosis) or w/hx of such a disorder Calcitonin: drug allergy, allergy to salmon Teriparatide: drug allergy Denosumab: hypocalcemia, renal impairment or failure, infection
Adverse Effects of Contraceptives
CV: Hypertension, edema, thromboembolism, pulmonary embolism, MI CNS: dizziness, headache, migraines, depression, stroke GI: N/V/D, anorexia, cramps, constipation, increased weight, cholestatic jaundice GU: amenorrhea, cervical erosion, breakthrough bleeding, dysmenorrhea, breast changes Other: alterations in serum metal and plasma protein levels, alterations in carb and lipid metabolism, increase in serum hormone concentrations. It is the estrogen component that appears to be source of most of these metabolic effects
Adverse Effects of Uterine Stimulants
CV: hypotension or hypertension, chest pain CNS: headache, dizziness, fainting GI: N/V/D GU: vaginitis, vaginal pain, cramping Other: leg cramps, joint swelling, chills, fever, weakness, blurred vision
Adverse Effects of Fertility Drugs
CV: tachycardia, deep vein thrombosis, hypovolemia CNS: dizziness, headache, flushing, depression, restlessness, anxiety, nervousness, fatigue GI: nausea, bloating, constipation, vomiting, anorexia Other: urticaria, ovarian hyperstimulation, multiple pregnancy (twins or more), blurred vision, diplopia, photophobia, breast pain
Mechanism of Action and Drug Effects
Clomiphene is nonsteroidal ovulation stimulant that blocks estrogen receptors in uterus and brain resulting in false signal of low estrogen levels to the brain. Hypothalamus and pituitary then increase production of Gn-RH from hypothalamus and FSH and LH (from pituitary) which stimulates maturation of ovarian follicles. Ideally, this leads to ovulation Menotropin (Pergonal): derived from urine of postmenopausal women; standardized mixture of FSH and LH, stimulates development of ovarian follicles, leading to ovulation, may also be given to men to stimulate spermatogenesis Chronic gonadotropin alfa (Ovidrel): recombinant form of human chorionic gonadotropin, causes rupture and ovulation of mature ovarian follicles, maintenance of corpus luteum, used to stimulate ovulation.
Interactions of Estrogens
Decrease activity of oral anticoagulants, and concurrent administration of rifampin and St. John's wort can decrease their estrogenic effect. use w/tricyclic antidepressants may promote toxicity of antidepressant. Smoking should be avoided b/c it can diminish effect and add to risk for thrombosis.
Drug Profile of Dinoprostone (Prostin E2, Cervidil, Prepidil)
Derivative of naturally occurring Prostaglandin E2. Used for termination of pregnancy from the 12-20th gestational weeks, for evacuation of uterine contents in the management of missed abortion or intrauterine fetal death up to 28 wks gestational age, for management of nonmetastatic gestation trophoblastic disease and for ripening of an unfavorable cervix in pregnant women at or near term when there is a medical or obstetric need for labor induction (available only for vaginal use)
Drug Profile of Calcitonin
Derived from salmon (fish) sources, available in both injectable and nasal form, nasal spray (Miacalcin) is now more commonly used
Mechanism of Action of Estrogens and Drug Effects
Development and maintenance of the female reproductive system Development of female secondary characteristics (Feminization) Shaping of body contours and development of the skeleton--long bones are usually inhibited from growing resulting in females being shorter than males. Produce their effects in estrogen-responsive tissues, which have a large number of estrogen receptors (such as genital organ, breasts, pituitary gland, hypothalamus) Production of estrogen increases greatly at time of puberty which causes initiation of menses, breast development, redistribution of body fat, softening of skin, other feminizing changes.
Drug Profile of methylergonovine (Methergine)
Ergot alkaloid, used primarily in immediately postpartal period to enhance myometrial tone and reduce likelihood of postpartum uterine hemorrhage contra: known hypersensitivity, pelvic inflammatory disease Should be used w/caution in pts w/hypertension Not to be used for augmentation of labor before delivery of placenta, during a spontaneous abortion, or given to pts w/pregnancy induced hypertension
About Contraceptive Drugs
Estrogen-Progestin combos often referred to as "the pill" are oral contraceptives that contain both estrogenic and progestational steroids. Most common estrogenic component is ethinyl estradiol (semisynthetic steroidal estrogen), most common progestin component is norethindrone. Monophasic and triphasic oral contraceptives are the most numerous on the market and the most widely prescribed
Indications of Estrogen
Hormone replacement therapy to counter estrogen deficiency is most commonly known for its benefits in treating menopausal symptoms (hot flashes) Atrophic vaginitis (shrinkage of vagina and or urethra), hypogonadism, oral contraception (in combo w/a progestin), ovarian failure or castration (or removal of ovaries), uterine bleeding, breast or prostate cancer (palliative treatment in advanced inoperable cases), osteoporosis (treatment and prophylaxis), vasomotor symptoms of menopause (hot flashes)
Drug Profile of Estrogen
Indicated for the treatment of many clinical conditions, particularly those that occur around menopause. A study from the Women's Health Initiative demonstrated the possible detrimental effects of estrogen and estrogen-progestin therapy. Results of women who took an estrogen-progestin combo product were found to have an increased risk of breast cancer, heart disease, stroke, and blood clots, although their risk of hip factures and colon cancer was reduced. The women in the study also identified adverse cognitive effects, they showed an increased risk of developing dementia and demonstrated reduced performance on test of cognitive function. A second study of hormone replacement therapy where women who had undergone hysterectomy received estrogen (alone) and the women were advised to stop taking their assigned medication b/c the therapy appeared to be associated w/increased risk of stroke. Also there was no effect on rates of coronary heart disease or breast cancer but it was associated w/a reduced rate of hip facture. Now understood that HRT is more beneficial for women who are just beginning menopause b/c it can treat menopause related symptoms and reduce the risk of osteoporosis or factures. HRT not recommended for women w/hx of endometrial cancer. Estrogen therapy has not proven safe in women w/breast cancer. When hormone therapy is discontinued after several years of use, assess bone-mineral density and begin treatment if indicated. Effects of all estrogens are similar b/c there are only slight difference in chemical structures and these difference yield drugs of different potencies which make for a variety of indications and routes of administration (highly customizable doses) Estrogen-progestin combo products are commonly referred to as continuous combined hormone replacement therapy. Use of estrogen alone has been associated w/increased risk of endometrial hyperplasia, a possible precursor of endometrial cancer. Addition of continuously administered protestin w/estrogen regimen reduces incidence of endometrial hyperplasia. Examples of combo products: conjugated estrogens w/medroxyprogesterone, norethindrone acetate w/ ethinyl estradiol, and estradiol w/norethindrone
Drug Profile of Medroxyprogesterone (Provera, Depo-Provera)
Inhibits section of pituitary gonadotropins which prevents follicular maturation and ovulation, stimulates growth of mammary tissue and has an antineoplastic action against endometrial cancer. Used to treat uterine bleeding, secondary amenorrhea, endometrial cancer, renal cancer and it is also a contraceptive. Most common use to prevent endometrial cancer caused by estrogen replacement therapy. Also sometimes used as adjunct therapy in certain types of cancer. Depo-Provera is long-lasting shot (once every 3 months) Concern about use in women younger than 25 year of age and use for longer than 2 years d/t potential for bone density loss.
Contraindications for Uterine Stimulants
Known drug allergy, pelvic inflammatory disease, cervical stenosis, uterine fibrosis, high-risk intrauterine fetal positions before delivery, placenta previa, hypertonic uterus, uterine prolapse or any condition in which vaginal delivery is contraindicated (increased bleeding risk). Contra to use of abortifacients: known drug allergy, present IUD, ectopic pregnancy, concurrent anticoagulant therapy or bleeding disorder, inadequate access to emergency health care or inability to understand or comply w/follow-up instructions
Contraindication of Contraceptives
Known drug allergy, pregnancy, known high risk for or hx of thromboembolic events such as myocardial infarction, venous thrombosis, pulmonary embolism or stroke
Adverse Effects of Progestin
Liver dysfunction commonly manifested as jaundice, thrombophlebitis, and thromboembolic disorder such as pulmonary embolism. GI: Nausea, vomiting GU: amenorrhea, spotting Other: edema, weight gain or loss, rash, pyrexia, somnolence or insomnia, depression
Interactions of Uterine Stimulants
Most common and important involve sympathomimetic drugs. Combo produces vasoconstriction and severe hypertension
Drug profile of Alendronate (Fosamax)
Oral bisphosphonate and the first nonestrogen nonhormonal option for preventing bone loss. Works by inhibiting and/or reversing osteoclast-mediated bone resorption. Indicated for prevention and treatment of osteoporosis in men and in postmenopausal women, also for treatment of glucocorticoid-induced osteoporosis in men and for treatment of Paget disease in women. Take precautions in pts w/dysphagia, esophagitis, esophageal ulcer, or gastric ulcer b/c drug can be irritating. Recommended that it be taken w/8 oz of water immediately upon waking in the morning and that the patient not lie down for at least 30 mins after taking it. Extremely long half-life so going several days w/o a dose will do little to reduce therapeutic efficacy. Recommended to remain on therapy for roughly 5 yrs.
Indications for Uterine Stimulants
Oxytocin (injectable form Pitocin) is used to induce labor and enhance labor when uterine contractions are weak and ineffective. Also used to prevent or control uterine bleeding after delivery, to induce completion of an incomplete abortion (following miscarriages) and to promote milk ejection during lactation Prostaglandins may be used to induce labor by softening cervix and enhancing uterine muscle tone. May also be used to stimulate myometrium to induce abortion during second trimester when uterus is resistant to oxytocin (dinoprostone and misoprostol) Misoprostol is also used as a stomach protectant. Misoprostol is administered orally or intravaginally and costs pennies which is why it is often used in the US even though prescribing info says it should not be used in this way. Ergot alkaloids are used after delivery to prevent postpartum uterine atony (lack of muscle tone) and hemorrhage Mifepristone is used to induce abortion and is often given w/misoprostol for this purpose
Interactions for Progestin
Possible decrease in glucose tolerance when taken w/antidiabetic drugs (dosage of antidiabetic drug may need to be adjusted Concurrent use of medroxyprogesterone or norethindrone and aminoglutethimide or rifampin induces increased metabolism of progestin
Mechanism of Action and Drug Effects of Contraceptives
Prevent ovulation by inhibiting release of gonadotropins and secondarily increase cervical mucus viscosity, resulting in: decreased sperm movement and fertilization of the ovum Thinning of endometrium, with possible inhibition of implantation of a fertilized egg (zygote) Improved menstrual cycle regularity Decrease blood loss during menstruation Decrease incidence of function ovarian cysts and ectopic pregnancies
Drug Profile of Megestrol (Megace)
Primarily used in palliative management of recurrent inoperable or metastatic endometrial or breast cancer. Can cause appetite stimulation and weight gain so it is also used in management of anorexia, cachexia, or unexplained substantial weight loss in pts w/AIDS and in pts w/cancer
Indications of Contraceptives
Primarily used to prevent pregnancy. Used to treat endometriosis and hypermenorrhea and to produce cyclic withdrawal bleeding in pts w/amenorrhea. Occasionally combo oral contraceptives are used to provide emergency contraception (not effective if woman is already pregnant) which is why they should be taken within 72 hrs of unprotected intercourse w/follow-up dose 12 hrs after first dose. Ex: Preven, Plan B, Alesse, Ella One oral contraceptive of note is Seasonale (extended cycle) which includes both estrogen and progestin components--sold in packages containing 3 mos worth of medication including 1 wks worth of nonhormonal tabs this is b/c it reduces a woman's menstrual cycle to once every 3 mos
Drug Profile of Clomiphene (Clomid)
Primarily used to stimulate production of pituitary gonadotropins which in turn induces maturation of ovarian follicle and eventually ovulation.
Mechanism of Action and Drug Effects of Progestin
Produce same physiologic responses as those produced by progesterone: Induction of secretory changes in endometrium, including diminished endometrial tissue proliferation; an increase in basal body temperature; thickening of the vaginal mucosa; relaxation of uterine smooth muscle,; simulation or mammary alveolar tissue growth; feedback inhibition (negative feedback) of release of pituitary gonadotropins (FSH and LH) and alterations in menstrual blood flow, especially in presence of estrogen
About Progestins
Progesterone is most active natural progestational hormone and it is produced by the corpus luteum after each ovulation and during pregnancy by the placenta Commonly used progestins: Hydroxyprogesterone (Hylutin), Levonorgestrel (Plan B), Medroxyprogesterone (Provera, Depo-Provera), Megestrol (Megace), Norethindrone acetate (Aygestin), Norgestrel (Ovrette, Ovral), Progesterone (Prometrium), Etonogestrel implant (Implanon)
Interactions of osteoporosis drugs
Raloxifene: cholestyramine and ampicillin decrease absortion; decreases effects of warfarin Bisphosphonates: aspirin and NSAIDs have potential for additive GI irritation calcium supplements and antacids can interfere w/absorption (need to be spaced 1-2 hrs apart) Calcitonin: calcium supplements more likely to cause hypercalcemia
Indications for Osteoporosis drugs
Raloxifene: primarily used for prevention of postmenopausal osteoporosis. Bisphosphonates: used in both prevention and treatment of osteoporosis Teriparatide: used primarily for subset of osteoporosis patient at higher risk of fracture (those w/prior facture) Calcitonin: treatment of osteoporosis
Drug Profile of Raloxifene (Evista)
SERM, used primarily for prevention of postmenopausal osteoporosis. Has positive effects on cholesterol level but not used specifically for this purpose. May not be best choice for women near menopause b/c use is associated w/hot flashes.
Adverse Effects of Osteoporosis Drugs
SERMs: primary AEs are hot flashes and leg cramps, can increase risk of venous thromboembolism and are teratogenic. Leukopenia may also occur and predispose the pt to various infections Bisphosphonates: most common are headache, GI upset, joint pain. Usually well tolerated. Risk of esophageal burns w/these medications if they become lodged in esophagus before reaching the stomach, for this reason pt must take w/a full glass of water and remain sitting upright or standing for at least 30 mins afterwards. Also reports of osteonecrosis of the jaw. Possible association to the development of severe (possibly incapacitating) bone, muscle, and/or joint pain as well as low energy fractures when using for long periods of time. Calcitonin: flushing of the face, nausea, diarrhea, and reduced appetite. Teriparatide: chest pain, dizziness, hypercalcemia, nausea, arthralgia Denosumab: infections occur more frequently
Interactions of Contraceptives
Several drugs can decrease effectiveness of contraceptives, educate pts about importance of using alternative contraceptives for at least 1 mo during and after taking antibiotics (esp penicillins and cephalosporins), barbiturates, isoniazid, rifampin. Effectiveness of anticonvulsants, beta-blockers, hypnotics, antidiabetic drugs, warfarin, theophylline, tricyclic antidepressants, and vitamins, may be reduced when taken w/oral contraceptives
Contraindications of Progestin
Similar to those for estrogen
Drug Profile of Oxytocin (Pitocin, Syntocinon)
Synthetic form of endogenous hormone oxytocin
About Estrogens
Three major endogenous estrogens: Estradiol (principal and most active), Estrone, Estriol Synthesized from cholesterol in ovarian follicles Basic chemical structure of a steroid referred to as steroid hormone Steroidal: conjugated estrogens, estradiol transdermal, estropipate, many others.
Adverse Effects of Estrogens
Thromboembolic events are the most serious; can also cause nausea, photosensitivity, chloasma (consists of brownish, macular spots that often occur on the forehead, cheeks, lips, and neck) CV: hypertension, thrombophlebitis, edema GI: N/V/D, constipation GU: Amenorrhea, breakthrough uterine bleeding, enlarged uterine fibromyomas Dermatologic: Chloasma (facial skin discoloration, also called melisma), hirsutism, alopecia Other: tender breast, fluid retention, decreased carb tolerance, headches
Interaction w/Fertility Drugs
Tricyclic antidepressants, butyrophenones (haloperidol), phenothiazines (promethazine) and antihypertensive drug methyldopa, when any of these are taken in conjunction w/fertility drugs prolactin concentrations may be increased which may impair fertility
Indications for Fertility Drugs
Used primarily for promotion of ovulation. May also be used to promote spermatogenesis in infertile men. Remember: Progesterone formulations are also used to treat female infertility.
About Uterine Stimulants
Used to either promote or prevent start or progression of labor. In immediate postpartum period, meds may be used to promote rapid shrinkage (involution) of uterus to reduce risk of postpartum hemorrhage. Often referred to as oxytocics b/c they mimic oxytocin which acts directly on the uterus and is secreted from the posterior lobe of the pituitary gland
About Infertility Drugs
Used to treat anovulation which can be caused d/t imbalances of hormones at the level of the hypothalamus, pituitary, or ovary. Hormone deficiencies at the hypothalamic and pituitary levels are often treated with gonadotropin ovarian stimulants. These drugs stimulate increased secretion of gonadotropin-releasing hormone (Gn-RH) from the hypothalamus, which then results in increased secretion of FSH and LH from the pituitary gland. These hormones, in turn, stimulate the development of ovarian follicles and ovulation. They also stimulate ovarian secretion of the estrogens and progestins that are part of the normal ovulatory cycle. Babies born through in vitro used to be referred to as "test tube babies"
Indications of Progestins
Useful in treatment of functional uterine bleeding caused by hormonal imbalance, fibroids, uterine cancer; treatment of primary or secondary amenorrhea; in adjunctive and palliative treatment of some cancer and endometriosis; an, alone or in combo w/estrogens in the prevention of conception. May also be helpful in preventing a threatened miscarriage and alleviating symptoms of premenstrual syndrome. Medroxyprogesterone is most commonly used. Norethindrone and norgestrel are commonly used alone or in combo w/estrogens as contraceptives. Megestrol is commonly used as adjunct therapy in treatment of breast and endometrial cancers. Progestin is often included w/estrogen therapies for women after menopause to decrease endometrial proliferation. Forms of progesterone are also used to treat female infertility
Mechanism of Action and Drug Effects of Uterine Stimulants
Uterus become more sensitive to oxytocin during pregnancy. Oxytocin stimulates uterine contraction during childbirth and during lactation it promotes the movement of milk from mammary glands to the nipples Prostaglandins (another class of oxytocic drugs) are involved in regulating network of smooth muscle fibers of the uterus (myometrium) and may also play a role in the natural induction of labor. When prostaglandin secretions increased during final weeks of pregnancy, mild myometrial contractions commonly known as Braxton Hicks are stimulated. Ergot alkaloids increase the force and frequency of uterine contractions. Progesterone antagonist mifepristone (Mifeprex) AKA the "abortion pill" also stimulates uterine contractions and is used to induce elective termination of pregnancy
Drugs for Preterm Labor
When contractions could progress to delivery prior to 37th week of pregnancy. Postponing delivery increases likelihood of infant's survival; however this measure is generally employed btw weeks 20-37 of gestation. Spontaneous labor occurring before week 20 is commonly associated w/nonviable fetus and is usually not interrupted. Non-pharmacologic treatment include bed rest, sedation, hydration. Tocolytics are drugs given to inhibit labor. Terbutaline (beta-adrenergic drug) used to be drug of choice for preterm labor--works by directly relaxing uterine smooth muscle, no longer used d/t maternal and fetal safety risks Magnesium sulfate is also used IV although efficacy is questioned. It is also used in pregnancy induced hypertension (have calcium gluconate readily available to reverse magnesium toxicity) Current recommendation for management of preterm labor include use of NSAID indomethacin and calcium channel blocker nifedipine. Indomethacin is the most effective tocolytic currently available and inhibits prostaglandin activity. Nifedipine inhibits myometrial activity by blocking calcium influx. Indomethacin is given w/Carafate to protect the stomach) When these treatments are ineffective and delivery is proceeding, corticosteroids (betamethasone or dexamethasone) are given to mother to promote lung maturity in fetus btw 24-34 wks gestation
Contraindications for Fertility Drugs
known drug allergy, primary ovarian failure, uncontrolled thyroid or adrenal dysfunction, liver disease, pituitary tumor, abnormal uterine bleeding, ovarian enlargement of uncertain cause, sex hormone-dependent tumors, and pregnancy