👶 Module 14 · Reproductive
11 drugs · 1 concepts · tested on the Final
💡 The big idea
A small module built around one question: are we trying to START something, STOP something, or REPLACE something? Start: labor (oxytocin, misoprostol), ovulation (clomiphene), erection (sildenafil). Stop: preterm labor and eclamptic seizures (terbutaline, magnesium sulfate) with betamethasone buying time for fetal lungs. Replace or block: estrogen, progesterone, testosterone, finasteride, tamsulosin.
🧠 How to think about this module
- Sort every drug by intent: stimulate the uterus, relax the uterus, or manipulate a sex hormone.
- Obstetric drugs are always assessed on two clients. The fetal heart rate is the second set of vital signs.
- The dangerous OB drugs — oxytocin and magnesium sulfate — are the ones with hold parameters. Learn the parameters, not the mechanism.
- Male genitourinary drugs split by target: prostate SIZE (finasteride shrinks it, over months) vs smooth muscle TONE (tamsulosin relaxes it, within days).
- Magnesium sulfate has one antidote and one early warning: calcium gluconate, and the loss of deep tendon reflexes.
🏷️ The whole module in 8 classes
Learn these groups and the drug list stops being 11 separate names.
| Class | What it does | Examples | What gets tested |
|---|
| Uterine stimulants (oxytocics) | Start or strengthen contractions and control postpartum hemorrhage. | oxytocin, misoprostol, methylergonovine, carboprost, dinoprostone | Tachysystole. Stop the oxytocin for more than 5 contractions in 10 minutes, contractions lasting over 90 seconds, or a non-reassuring fetal heart rate — then reposition to the left side, give oxygen, increase the maintenance IV, and call. Methylergonovine is contraindicated in hypertension. |
| Tocolytics | Relax the uterus to delay preterm birth long enough for steroids to work. | terbutaline, magnesium sulfate, nifedipine, indomethacin | Terbutaline causes maternal tachycardia, tremor, and hyperglycemia; the FDA warns against prolonged use beyond 48 to 72 hours. Indomethacin is limited to under 32 weeks because of ductus arteriosus closure. |
| Magnesium sulfate | Seizure prophylaxis in preeclampsia and eclampsia, and fetal neuroprotection before 32 weeks. | magnesium sulfate IV | Hold the infusion and call for absent deep tendon reflexes, a respiratory rate under 12, or urine output under 30 mL/hr. Calcium gluconate is the antidote and stays at the bedside. Expect flushing and warmth — that is normal. |
| Antenatal corticosteroids | Given to the mother to accelerate fetal lung maturity. | betamethasone, dexamethasone | Two IM doses 24 hours apart, typically between 24 and 34 weeks, given as soon as preterm birth is anticipated because benefit begins around 24 hours after the first dose. Maternal blood glucose rises — monitor closely in diabetes. |
| Fertility agents | Induce ovulation. | clomiphene, letrozole, gonadotropins, human chorionic gonadotropin | Multiple gestation and ovarian hyperstimulation syndrome. Sudden abdominal distension, rapid weight gain, or shortness of breath needs immediate evaluation. Teaching centers on timing intercourse to the ovulation window. |
| Estrogens and progestins | Supply or replace sex hormones for contraception, menopausal symptoms, or luteal support. | conjugated estrogens, estradiol; progesterone, medroxyprogesterone; combined oral contraceptives | Thromboembolism, stroke, and MI risk, sharply higher with smoking over age 35 — that combination is a contraindication, not a caution. Teach the ACHES warning signs. Take an oral contraceptive at the same time daily. |
| Androgens and antiandrogens | Replace testosterone, or block its conversion to dihydrotestosterone. | testosterone (gel, patch, IM); finasteride, dutasteride | Testosterone gel transfers by skin contact — cover the site, wash hands, and keep children and pregnant partners away. Finasteride is absorbed through skin and is teratogenic; it also lowers PSA by about half, which can mask prostate cancer. |
| Prostate and erectile agents | Relax smooth muscle in the bladder neck or in penile vasculature. | tamsulosin, alfuzosin (alpha-1 blockers); sildenafil, tadalafil (PDE-5 inhibitors) | Tamsulosin causes orthostatic hypotension and dizziness — first dose at bedtime — and intraoperative floppy iris syndrome, so the client must tell an eye surgeon they take it. Sildenafil with any nitrate is an absolute contraindication. |
⚖️ Oxytocin vs magnesium sulfate — opposite jobs, both with hold parameters
| Oxytocin | Magnesium sulfate |
|---|
| Makes the uterus CONTRACT: induction, augmentation, postpartum hemorrhage | RELAXES the uterus and prevents eclamptic seizures |
| Hold for more than 5 contractions in 10 minutes, contractions over 90 seconds, or a non-reassuring fetal heart rate | Hold for absent deep tendon reflexes, respiratory rate under 12, or urine output under 30 mL/hr |
| Risk: uterine rupture, fetal distress, water intoxication at high doses | Risk: respiratory depression, cardiac arrest, neonatal depression |
| No antidote — stop the infusion, turn to the left side, oxygen, increase the maintenance IV, call | Antidote: calcium gluconate, kept at the bedside |
🚨 Red flags DANGER
- Absent deep tendon reflexes on magnesium sulfate: stop the infusion and give calcium gluconate. Reflexes disappear BEFORE respirations fail — that is the warning you act on.
- Sildenafil, tadalafil, or vardenafil with nitroglycerin or any nitrate: potentially fatal hypotension. Ask about them in every chest pain assessment.
- Oxytocin tachysystole with a non-reassuring fetal heart rate: stop the oxytocin, reposition to the left lateral side, increase the maintenance IV, apply oxygen by mask, and call.
- A pregnant person must never handle crushed or broken finasteride tablets or come into skin contact with testosterone gel. Both are teratogenic through the skin.
- Misoprostol given to a pregnant client for ulcer prevention causes miscarriage — it is contraindicated for that indication even though it is used deliberately in obstetrics.
🧵 Exam traps ⭐ HIGH YIELD
- Misoprostol appears twice in this course with opposite intentions. As a GI protectant it is forbidden in pregnancy; in obstetrics it is used deliberately to ripen the cervix. Read the indication in the stem.
- Terbutaline is a beta-2 agonist. It shows up in asthma and in preterm labor — same drug, same mechanism, different chapter.
- Betamethasone here is given to the mother for the FETAL lungs. In the skin module it is a topical steroid for dermatitis. Same drug, unrelated uses.
- Magnesium toxicity announces itself neurologically first (lost reflexes), not respiratorily. Waiting for the respiratory rate to fall is waiting too long.
- Finasteride and tamsulosin both treat BPH but on different timelines — finasteride takes 3 to 6 months, tamsulosin works within days. 'Why isn't it working yet?' questions are about finasteride.
- Clomiphene's most-tested adverse outcome is multiple gestation, and the client must be taught this before the first cycle.
🧠 Ways to remember it
- ACHES for estrogen warning signs: Abdominal pain, Chest pain, Headache, Eye problems, Severe leg pain.
- Magnesium: reflexes go first, then respirations. Calcium gluconate at the bedside.
- Ox pulls (oxytocin contracts). Mag relaxes.
- Nitrates plus sildenafil: no way, no how.
- Betamethasone before birth = Baby's Breath.
🧠 The concepts 1
Magnesium sulfate🚨 DANGER
In obstetrics, magnesium sulfate is given IV to PREVENT AND TREAT SEIZURES in preeclampsia and eclampsia. It is also used for fetal neuroprotection in preterm birth under 32 weeks and for short-term tocolysis. It is a CNS depressant and smooth muscle relaxant, and a high-alert drug.
- The FIRST sign of toxicity is LOSS OF DEEP TENDON REFLEXES. Check the patellar reflex before each dose and hourly during infusion.
- HOLD the infusion and notify the provider for absent DTRs, respirations under 12 to 16 per minute, urine output under 30 mL/hr (magnesium is renally cleared), or a decreased level of consciousness.
- ANTIDOTE: CALCIUM GLUCONATE IV. Keep it at the bedside whenever magnesium is infusing.
- Therapeutic serum range in preeclampsia is roughly 4 to 7 mEq/L (normal is 1.3 to 2.1). Levels around 10 and above cause respiratory paralysis, then cardiac arrest.
- Flushing, warmth, sweating, and lethargy are expected, not toxicity. Monitor the fetal heart rate; the newborn may be hypotonic. Non-obstetric uses: torsades de pointes, severe asthma exacerbation, and hypomagnesemia.
Reflexes, Respirations, urine Output. Lose a reflex, stop the drip and grab calcium gluconate.
💉 The drugs 11
💉 Betamethasone
Corticosteroid, topical
What it is for
Inflammation/itching corticosteroid-responsive dermatoses on the skin/scalp
How it works
Crosses cell membrane to attach to receptors to decrease inflammation, itching; inhibits multiple inflammatory cytokines
Watch for
- INTEG Burning, folliculitis, pruritus, dermatitis, maceration, erythema
- MISC Hyperglycemia, glycosuria, Cushing’s syndrome, HPA axis suppression
Teaching
- Topical route:
- That betamethasone valerate may be used with occlusive dressings for psoriasis or recalcitrant conditions; not to use dipropionate with occlusive dressings
- Avoid use of topical corticosteroids on face
- Cream/ointment/lotion:
🔗 Full card in the drug guide
💉 EstrogensHIGH ALERTBLACK BOX
Estrogen, hormone
What it is for
Vasomotor symptoms (menopause), inoperable breast cancer, prostatic cancer, abnormal uterine bleeding, hypogonadism, primary ovarian failure, prevention of osteoporosis, castration, atrophic vaginitis
How it works
Needed for adequate functioning of female reproductive system; affects release of pituitary gonadotropins, inhibits ovulation; adequate calcium use in bone
Watch for
- CNS Dizziness, headache, migraine, depression, seizures, mood disturbances
- CV Hypertension, thrombophlebitis, edema, thromboembolism, stroke, pulmonary embolism, MI, chest pain
- EENT Contact lens intolerance, increased myopia, astigmatism
- GI Nausea, vomiting, diarrhea, anorexia, pancreatitis …
Teaching
- To avoid breastfeeding; product is excreted in breast milk
- To weigh weekly; to report gain >5 lb
🔗 Full card in the drug guide
💉 Finasteride
Hormone, androgen inhibitor, hair stimulant, 5-α-Reductase inhibitor
What it is for
Symptomatic benign prostatic hyperplasia (Proscar); male-pattern baldness (Propecia)
How it works
Inhibits 5-α-reductase and reduction in DHT; DHT induces androgenic effects by binding to androgen receptors in the cell nuclei of the prostate gland, liver, skin; prevents development of BPH
Watch for
- GU Impotence, decreased libido, decreased volume of ejaculate, sexual dysfunction, gynecomastia
- INTEG Rash
- MISC Breast tenderness, secondary malignancy, angiedema
Teaching
- That volume of ejaculate may be decreased during treatment; that impotence and decreased libido may also occur and may continue after discontinuing treatment
- That Propecia results may not occur for 3 mo
- That Proscar results may not occur for 6-12 mo
- Advise patient to take as directed, not to skip or double doses, up to 12 mo may be required
🔗 Full card in the drug guide
💉 MisoprostolBLACK BOX
Gastric mucosa protectant, antiulcer, Prostaglandin E1 analog
What it is for
Prevention of NSAID-induced gastric ulcers, pregnancy termination
Black box warning
⚠️ Pregnancy, females
🔗 Full card in the drug guide
💉 OxytocinHIGH ALERTBLACK BOX
Hormone, Oxytocic, uterine-active agent
What it is for
Stimulation, induction of labor; missed or incomplete abortion; postpartum bleeding
How it works
Acts directly on myofibrils, thereby producing uterine contraction; stimulates milk ejection by the breast; vasoactive antidiuretic effect
Watch for
- CNS Seizures, tetanic contractions
- CV Hypo/hypertension, dysrhythmias, increased pulse, bradycardia, tachycardia, PVC
- FETUS Dysrhythmias, jaundice, hypoxia, intracranial hemorrhage
- GI Anorexia, nausea, vomiting, constipation
- GU Abruptio placentae …
Teaching
- To report increased blood loss, abdominal cramps, fever, foul-smelling lochia, nausea, blurred vision, itching, swelling
- That contractions will be similar to menstrual cramps, gradually increasing in intensity
- Side effects: italics = common; red = life-threatening
- Canada only
🔗 Full card in the drug guide
💉 ProgesteroneBLACK BOX
Hormone, Progestogen, Progesterone derivative
What it is for
Contraception, amenorrhea, premenstrual syndrome, abnormal uterine bleeding, endometrial hyperplasia prevention, assisted reproductive technology (ART) gel
How it works
Inhibits secretion of pituitary gonadotropins, which prevents follicular maturation, ovulation; stimulates growth of mammary tissue; antineoplastic action against endometrial cancer
Watch for
- CNS Dizziness, headache, depression, fatigue, mood swings
- CV Hypotension, thrombophlebitis, edema, thromboembolism, stroke, pulmonary embolism, MI
- EENT Diplopia, retinal thrombosis
- GI Nausea, vomiting, anorexia, cramps, increased weight, cholestatic jaundice, constipation …
Teaching
- To report breast lumps, vaginal bleeding, edema, jaundice, dark urine, claycolored stools, dyspnea, headache, blurred vision, abdominal pain, numbness or stiffness in leg …
- To avoid gel with other vaginal products; if to be used together, to separate by ≥6 hr; for vaginal route, on proper insertion technique
- To report suspected pregnancy
- To monitor blood glucose if diabetic
🔗 Full card in the drug guide
💉 Sildenafil
Erectile agent, antihypertensive, pulmonary vasodilator, Phosphodiesterase type-5 inhibito
What it is for
Treatment of erectile dysfunction (Viagra); improvement in exercise ability, pulmonary hypertension (Revatio, LiQrev)
How it works
Enhances the effect of nitric oxide (NO) by inhibiting phosphodiesterase type 5 (PDE5), which is necessary for degrading cGMP in the corpus cavernosum
Watch for
- CNS Headache, flushing, dizziness, transient global amnesia, seizures
- CV MI, sudden death, CV collapse, TIAs, ventricular dysrhythmias, CV hemorrhage
- MISC Dyspepsia, nasal congestion, UTI, abnormal vision, diarrhea, rash, nonarteritic ischemic optic neuropathy, hearing loss, priapism …
Teaching
- That product does not protect against sexually transmitted diseases, including HIV
- That product absorption is reduced with a high-fat meal, to take on empty stomach for faster action; to take 30 min to 4 hr before sexual activity; peak is 2 hr
- That product should not be used with nitrates or soluble guanylate cyclase stimulators (riociguat) (PAH)
- That tabs may be split
🔗 Full card in the drug guide
💉 Tamsulosin
Selective α1-peripheral adrenergic blocker, BPH agent, Sulfamoylphenethylamine derivative
What it is for
Symptoms of benign prostatic hyperplasia (BPH)
How it works
Binds preferentially to α1A- adrenoceptor subtype, which is located mainly in the prostate
Watch for
- CNS Dizziness, headache, asthenia, insomnia
- CV Chest pain, orthostatic hypotension
- EENT Amblyopia, floppy iris syndrome
- GI Nausea, diarrhea, dysgeusia
- GU Decreased libido, abnormal ejaculation, priapism
- INTEG Rash, pruritus, urticaria
- MS Back pain
- RESP Rhinitis, pharyngitis …
Teaching
- Not to drive or operate machinery for 4 hr after 1st dose or after dosage increase
- To continue to take even if feeling better
- To advise providers of all products, herbs taken
- To make position changes slowly because orthostatic hypotension may occur
🔗 Full card in the drug guide
💉 TerbutalineBLACK BOX
Selective β2-agonist; bronchodilator, Catecholamine
What it is for
Bronchospasm Unlabeled: Premature labor
How it works
Relaxes bronchial smooth muscle by direct action on β2-adrenergic receptors through the accumulation of cAMP at β-adrenergic receptor sites; bronchodilation, diuresis, CNS, cardiac stimulation occur; relaxes uterine smooth muscle
Watch for
- CNS Tremors, anxiety, insomnia, headache, dizziness, stimulation, restlessness
- CV Palpitations, tachycardia, hypertension, dysrhythmias, cardiac arrest, QT prolongation
- GI Nausea, vomiting
- META Hypokalemia, hyperglycemia
- RESP Paradoxical bronchospasm …
Teaching
- Avoid cough/cold/allergy OTC medications because extra stimulation may occur
- About all aspects of product; to avoid smoking, smoke-filled rooms, persons with respiratory infections
- To maintain adequate hydration; to allow 15 min between inhalation of product and inhaled product containing steroid
- To take on time; if missed, not to make up after 1 hr; to wait until next dose
🔗 Full card in the drug guide
💉 Testosterone
Androgen
What it is for
Breast cancer, metastatic (females); advancing inoperable metastatic (skeletal) mammary cancer who are 1-5 yr postmenopausal; delayed puberty (males)
🔗 Full card in the drug guide
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Where this came from. The drug cards come from your own drug guide, fact-checked against FDA labeling. The explanations were written from your course textbook,
Pharmacology (WTCS, 2e). If anything here contradicts your instructor, believe your instructor — they write the exam.