Reproductive and Urinary System Medications Study Guide

Introduction to Reproductive System Hormones

  • Gonadotropic Hormones     - These hormones are responsible for the optimal functioning of both the testes and the ovaries.     - They are secreted by the pituitary gland.     - Follicle-stimulating hormone (FSH): This hormone regulates the production of sperm in males and eggs in females.     - Luteinizing hormone (LH): This hormone triggers the release of the egg (ovulation) and promotes the secretion of estrogen and progesterone.     - Interstitial cell-stimulating hormone (ICSH): This is the male equivalent of LH; it regulates the production of testosterone.

Female Reproductive Hormones Produced in the Ovaries

  • Estrogens     - Primary forms include estradiol, estrone, and estriol.     - Mechanism: Estrogens enter cells and bind to receptors within the cytoplasm, where they promote messenger RNA (mRNA) activity.

  • Progesterone     - This hormone is released into circulation after ovulation has occurred.     - It is essential for supporting the early development of the fetus.

Male Reproductive Hormone: Testosterone

  • Testosterone is responsible for various physiological developments and maintenance tasks, including:     - Growth of male sexual accessory organs.     - Growth of the testes and the scrotal sac.     - Thickening of the vocal cords.     - Hair growth and male-pattern baldness.     - Increased protein anabolism and decreased protein catabolism.     - Increased bone growth.     - Thickening of the cartilage and skin.     - Vascular thickening.     - Increased hematocrit levels.

Contraceptive Medications: Principles and Types

  • Mechanism of Action     - Administration of exogenous estrogen and progestin causes the body to stop its natural production of these hormones.     - Low doses inhibit the ability to conceive through:         - Inhibition of ovulation.         - Inhibition of fertilization.         - Prevention of implantation.         - Prevention of fetal growth.

  • Oral Contraceptive Pills (“The Pill”)     - Monophasic Pills: These provide a constant amount of hormones for the first 2121 days of the cycle.         - Examples: Ethinyl estradiol and norgestrel (Cryselle 28, Lo/Ovral 28, Ogestrel-28); Ethinyl estradiol and norethindrone (Aranelle, Ortho-Novum).     - Biphasic Pills: These provide a constant dose of estrogen but two different doses of progestin during the monthly cycle to allow the uterine lining to develop normally.         - Examples: Ethinyl estradiol and norethindrone (Jenest-28); Ethinyl estradiol and desogestrel (Apri, Ortho-Cept).     - Triphasic Pills: These contain varying amounts of estrogen and progestin in three different strengths throughout the cycle.         - Examples: Ethinyl estradiol and norethindrone (Aranelle, Ortho-Novum 7/7/7); Ethinyl estradiol and levonorgestrel (Alesse, Portia).     - Mini Pill: Contains only progestin and is slightly less effective than combination pills.         - Examples: Progestin (Errin, Provera).     - Symptoms: Users may experience symptoms similar to those of pregnancy.

  • Emergency and Alternative Contraceptives     - Postcoital High-Dose Estrogen: Used when contraception fails or is used improperly to prevent pregnancy.         - Examples: Levonorgestrel emergency contraceptive (Plan B); Ethinyl estradiol and levonorgestrel (Preven).     - Contraceptive Ring: A flexible ring containing estrogen and progestin inserted into the vagina monthly; it is removed after 33 weeks to allow for menstruation.     - Contraceptive Implant: A small plastic rod placed in the upper arm that prevents ovulation and inhibits sperm; effective for up to 33 years.         - Example: Etonogestrel (Implanon).     - Intrauterine Device (IUD):         - Levonorgestrel intrauterine system (Mirena): Contains progestin, makes the environment hostile to sperm and implantation; effective for 55 years.         - Copper IUD: Naturally toxic to sperm; effective for 1010 years.     - Transdermal Contraceptive Patch: Ethinyl estradiol and norelgestromin (Ortho Evra patch); a new patch is applied weekly for 33 weeks, followed by one week off.

  • Risks and Barriers     - Hormonal Risks: Increased risk of blood clots, especially in women older than 3535 years or those who smoke.     - Barrier Devices: Condoms and diaphragms; often used with spermicides like nonoxynol-9 (Encare, Conceptrol). These are the only methods effective against sexually transmitted diseases (STDs).     - Mifepristone (Mifeprex): Formerly RU-486. It blocks progesterone and is used within the first 77 weeks of the last menstrual period. Contraindicated for patients on blood thinners.

Hormone Replacement Therapy (HRT) in Women

  • Indications: Used for women experiencing menopause to replace naturally declining hormones.

  • Regimens:     - If the uterus has been removed: Estrogen alone.     - If the uterus is intact: Estrogen combined with progestin.

  • Formulations:     - Oral: Estrace, Premarin.     - Cream: Estrace, Dienestrol.     - Patch: Estraderm, Vivelle.     - Combination: Prempro (Pill), Climara-Pro (Patch).     - Estrogen/Testosterone Combination: Used to relieve specific menopause symptoms (Covaryx, Estratest).

  • Clinical Considerations:     - Benefits: Decreases bone loss and cardiovascular dysfunction.     - Risks: Increased risk of breast cancer, stroke, and blood clots.

Pharmacology of Estrogens and Progestins

  • Estrogens     - Actions: Affect FSH/LH release, cause fluid retention, thin cervical mucus, conserve calcium/phosphorus, and inhibit ovulation.     - Systemic Effects: Maintain secondary sex characteristics, protect the heart from atherosclerosis, and retain calcium in bones.     - Contraindications: Pregnancy, idiopathic vaginal bleeding, breast/estrogen-dependent cancer, history of thromboembolic disorders, heavy smoking, and hepatic dysfunction.     - Interactions: Drugs affecting CYP3A4, corticosteroids, anticoagulants, thyroid medications, and oral diabetes drugs.

  • Progestins     - Actions: Transform proliferative endometrium into secretory endometrium, inhibit FSH/LH secretion, and inhibit uterine contractions.     - Indications: Amenorrhea, functional uterine bleeding, and fertility programs.     - Adverse Effects: Drospirenone carries a specific risk for hyperkalemia.     - Interactions: Barbiturates, carbamazepine, phenytoin, penicillins, tetracyclines, and St. John’s wort.

Androgen Therapy and Male HRT

  • Indications for Men: Used for male menopause or prostate cancer (where estrogen is used to decrease testosterone).     - Testosterone Replacement: May decrease risks of heart disease and diabetes (e.g., AndroGel).

  • Androgens Pharmacology     - Actions: Increase nitrogen, sodium, and potassium retention; increase red blood cell production; increase protein anabolism.     - Indications: Hypogonadism, certain breast cancers in females, and endometriosis (Danazol).     - Adverse Effects: Virilization in prepubescent males; inhibition of testicular function, gynecomastia, and priapism in postpubescent males; hepatocellular cancer.

Medications for Labor and Abnormal Bleeding

  • Abnormal Uterine Bleeding: Treated with oral contraceptives (estrogen/progesterone) or Gonadotropin-releasing hormone agonists like Leuprolide (Eligard, Lupron) and Goserelin (Zoladex).

  • Labor Induction/Ripening:     - Cervical Ripening: Dinoprostone (Prepidil) softens the cervix.     - Oxytocin (Pitocin): Causes uterine contractions; used for induction or to control postpartum bleeding.

  • Tocolytics (Stopping Labor):     - Terbutaline (Brethine): Short-term use (2424 to 4848 hours).     - Magnesium Sulfate: Treats preeclampsia and slows labor; may prevent cerebral palsy.     - Nifedipine (Adalat CC): Oral calcium channel blocker to relax uterine smooth muscle.     - Indomethacin (Indocin): NSAID used for less than 77 days; avoided in the last 22 months of pregnancy due to fetal cardiac risks.

Infertility and Other Disorders

  • Ovulation Stimulants:     - Clomiphene (Clomid): Increases FSH and LH.     - Menotropins (Menopur): Stimulates follicle ripening.     - Chorionic gonadotropin (Ovidrel): Stimulates the release of the egg.

  • Sexual Health:     - Erectile Dysfunction (ED): Treated with PDE5 inhibitors (Sildenafil, Vardenafil, Tadalafil) or Alprostadil (Caverject). PDE5 inhibitors are contraindicated with organic nitrates.     - STDs: Metronidazole (Trichomonas), Acyclovir (Herpes), Miconazole (Yeast).

The Urinary System and Diuretics

  • System Functions: Volume/composition regulation, Vitamin D activation, BP regulation (RAAS), and erythropoietin secretion.

  • Loop Diuretics (Most Effective):     - Act on the loop of Henle; inhibit sodium/chloride reabsorption.     - Examples: Furosemide (Lasix), Bumetanide (Bumex), Torsemide (Demadex).

  • Thiazide Diuretics:     - First-line for essential hypertension.     - Examples: Hydrochlorothiazide, Chlorothiazide, Metolazone.

  • Potassium-Sparing Diuretics:     - Minimize K loss; Spironolactone is the drug of choice for hyperaldosteronism.

  • Osmotic Diuretics:     - Mannitol (Osmitrol) used for intracranial or intraocular pressure.

Urinary Disorders and Prostate Health

  • Benign Prostatic Hypertrophy (BPH): Treated with Alpha-adrenergic blockers like Tamsulosin (Flomax), Dutasteride (Avodart), and Finasteride (Proscar).

  • UTI and Spasms:     - Antibiotics: Bactrim, Augmentin.     - Analgesics: Pyridium (may turn urine orange/red).     - Antispasmodics/Anticholinergics: Oxybutynin (Ditropan XL), Tolterodine (Detrol), Solifenacin (VESIcare).

  • Urine Color Changes: Antibiotics, anticoagulants, and laxatives can change urine to brown, blue-green, orange, or red. This is usually harmless but requires patient education.