Pharmacology, part 42: Reproductive Medications - Estrogen, Progesterone, Uterine Stimulants, Tocolytic Agents

September 20, 2021 Updated: January 10, 2022 8 min read

In this article, we cover the reproductive system medications estrogens and progestin, as well as uterine stimulants and tocolytic agents.

The Nursing Pharmacology video series follows along with our Pharmacology Second Edition Flashcards, which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.

Cool Chicken When you see this Cool Chicken, that indicates one of Cathy's silly mnemonics to help you remember. The Cool Chicken hints in these articles are just a taste of what's available across our Level Up RN Flashcards for nursing students!

Estrogens - conjugated estrogen, estradiol (Estrace)

Estrogens, which include conjugated estrogen and estradiol, are indicated for contraception, post-menopausal osteoporosis, dysmenorrhea (painful menstruation; used in a combination estrogen/progesterone), or for prostate cancer.

Estrogens - mode of action

These medications bind to estrogen receptors in the body, promoting growth and development of female sex organs and secondary sex characteristics in women.

Estrogens - side effects

The main side effects of estrogens include embolic effects (i.e., blood clots). A patient taking estrogen is at higher risk for DVT, PE, an MI (myocardial infarction, or “heart attack”), or a stroke. Other side effects include hypertension, weight gain, edema (swelling caused by excess fluid trapped in the body's tissues), and increased risk of certain types of cancer, for example, estrogen-dependent breast cancers.

Estrogens - contraindications

This medication is contraindicated in patients who smoke, have hypertension, or who are at increased risk for blood clotting (embolic events). As noted above, some breast cancers are estrogen-dependent — a patient with an estrogen-dependent cancer should not be treated with estrogen.

Progesterones - medroxyprogesterone (Depo-Provera), norethindrone

Progesterones, which include medroxyprogesterone and norethindrone, can be used for contraception, either alone or in combination with estrogen. They can also be used in the treatment of dysmenorrhea (painful menstruation).

Progesterones - mode of action

Progesterones inhibit gonadotropin production, preventing follicular maturation and ovulation.

Progesterones - side effects

The side effects of progesterone include an increased risk for embolic events or blood clots, just as with estrogen — patients taking progesterone are at increased risk for DVT, PE, MI, and stroke; menstrual changes; edema; and an increased risk of breast cancer.

The injectable medication medroxyprogesterone (Depo-Provera) comes with an increased risk for bone loss.

Progesterones - contraindications

Progesterone is contraindicated for any patient who is at increased risk for blood clots.

This medication carries a black box warning due to the risk of decreased bone mineral density in patients who use Depo-Provera or injectable medroxyprogesterone. Patients being administered this medication should be encouraged to increase their intake of calcium and vitamin D.

Oxytocic - oxytocin (Pitocin)

Oxytocin and dinoprostone are medications used in the induction and enhancement of labor. Oxytocin may also be used in the treatment of postpartum hemorrhage.

Oxytocin - mode of action

Oxytocin works by stimulating the uterus.

Oxytocin - side effects

Side effects can include painful contractions, uterine rupture, and water intoxication (a form of acute hyponatremia, that is, abnormally low sodium).

Oxytocin - nursing care

A patient on oxytocin should have their contractions closely monitored — contractions should be 60 – 90 seconds in duration and occur every 2 – 3 minutes. If contractions are happening more frequently or lasting longer, it may be necessary to discontinue oxytocin. It will also be important to monitor maternal and fetal blood pressure and pulse.

Note that magnesium sulfate may be used to help relax the uterus if hyper-stimulation of the uterus occurs due to oxytocin.

Uterine stimulant - methylergonovine (Methergine)

Methylergonovine is another uterine stimulant and is used for postpartum hemorrhage.

Methylergonovine - mode of action

Methylergonovine has the same mode of action as oxytocin, that is, it stimulates the uterus.

Methylergonovine - side effects

Side effects can include abdominal pain, nausea and vomiting, and hypertension.

Methylergonovine - contraindications

A patient who has hypertension should not receive this medication.

Tocolytic (preterm labor) - terbutaline (Bricanyl)

Terbutaline is a tocolytic agent used in the treatment of preterm labor. It helps to delay labor but will not prevent it.

Cool Chicken When flying, turbulence delays arrival time (just like terbutaline delays arrival of the baby).

Terbutaline is also used for asthma and COPD.

Terbutaline - mode of action

The mode of action of terbutaline is to activate Beta-2 receptors, which helps to relax the uterus.

It also causes bronchodilation, which is why it's used to treat asthma and COPD.

Terbutaline - side effects

This medication has many side effects, including tachycardia, angina, hypokalemia (low blood levels of potassium), dysrhythmias (irregular beating of the heart), restlessness, and tremor.

Note that this medication comes with a black box warning due to the risk for significant maternal and fetal distress if it’s used for more than 48 hours.

Terbutaline - contraindications

Terbutaline is for short-term use only — under 48 hours (as noted above). Its use should be limited to pregnancies under 37 weeks in gestation.

Remember that there are other tocolytic agents that can be used for preterm labor, including magnesium sulfate, as well as nifedipine, which is a calcium channel blocker.


Full Transcript

Hi, I'm Cathy, with Level UP RN. In this video, I'm going to begin my coverage of reproductive system medications. Specifically, I'll be covering estrogens, progestin, as well as uterine stimulants, and tocolytic agents. If you have our pharmacology addition to flashcards, be sure to pull those out. I am in the reproductive system. Those are purple cards, and you can follow along. At the end of the video, I'm going to provide you guys a quick little knowledge check to test your understanding of some of the key information I'll be covering in this video. So definitely, stay tuned for that.

First up, we have our estrogens, which include conjugated estrogen and estradiol.

So these medications will bind to estrogen receptors in the body, and they are used for contraception as well as postmenopausal osteoporosis. It can also be used for dysmenorrhea, so that's painful menstruation as well as prostate cancer.

Key side effects of estrogens include embolic effects, so blood clots. So taking estrogen places the patient at higher risk for a DVT, a PE, as well as an MI or a stroke. Other side effects include hypertension, weight gain, edema, and increased risk of certain types of cancer. So some breast cancers are estrogen-dependent. So if a patient has that type of cancer, we absolutely would not want them to take an estrogen.

Key points, this medication is contraindicated in patients who smoke, who have hypertension, or who are at increased risk for blood clotting. So those are all contraindications with estrogen.

Next, we have our progesterone, which include medroxyprogesterone as well as norethindrone.

These medications can be used for contraception, so either alone or in combination with estrogen. It can also be used in the treatment of dysmenorrhea.

So side effects will include an increased risk for embolic events or blood clots, just like what we saw with estrogen. So progesterone would be contraindicated for any patient who is at increased risk for blood clots. Other side effects include menstrual changes, edema, an increased risk for breast cancer. Also, with injectable medroxyprogesterone, which is Depo-Provera, we have an increased risk for bone loss.

In fact, this medication carries a black box warning due to the risk of decreased bone mineral density in patients who use Depo-Provera or injectable medroxyprogesterone. So for those patients, we're definitely going to want to encourage them to increase their intake of calcium and vitamin D to help counteract that side effect.

Now let's talk about some uterine stimulants, which include oxytocin as well as dinoprostone. These medications are used in the induction and enhancement of labor.

Oxytocin is also used in the treatment of postpartum hemorrhage.

The mode of action is to stimulate the uterus, and side effects can include painful contractions as well as uterine rupture. So I can definitely attest to the painful contractions because I did receive oxytocin when I was in labor with my children. So when your patient is on a medication such as oxytocin, you're going to want to closely monitor their contractions. So contractions should be between 60 and 90 seconds in duration, and they should occur every two to three minutes. If our contractions are happening more frequently than that or are lasting longer than that, then that's a problem, and we may need to [de-see] the oxytocin.

Also, keep in mind that magnesium sulfate can be used to help relax the uterus if we are dealing with hyper-stimulation of the uterus due to oxytocin. We also want to keep an eye on mom's blood pressure and pulse, as well as the fetal blood pressure and pulse.

Another uterine stimulant to know is methylergonovine, which I practice saying 5000 times before I hit record. So this medication is used for postpartum hemorrhage.

It has the same mode of action as oxytocin, so it stimulates the uterus.

Side effects can include abdominal pain, nausea and vomiting, and hypertension. So any patient who has hypertension should not receive this medication because of that side effect of hypertension.

The last medication I want to cover in this video is terbutaline, which is a tocolytic agents that is used in the treatment of pre-term labor. So it helps to delay labor but will not prevent it.

So our little-cool chicken hint here on this card to help you remember this medication, and what it's for is when flying, like an airplane, turbulence will possibly delay your arrival time, just like terbutaline delays the arrival of the baby.

So another thing that terbutaline is used for is asthma, as well as COPD.

So the mode of action of terbutaline is that it activates Beta-2 receptors, and it does that in the lungs, so it causes bronchodilation, which is why it's used for asthma and COPD. It also relaxes the uterus, which is why it's used for pre-term labor.

This medication carries a lot of side effects, including tachycardia, restlessness, and tremor.

Also, this medication has a black box warning due to the risk for significant maternal and fetal distress if it's used for over 48 hours.

So a key point with this medication is that we only want to use it for short-term use, so under 48 hours. We should also use this for pregnancies under 37 weeks in gestation. Keep in mind, there are some other tocolytic agents that can be used for pre-term labor, which include magnesium sulfate, as well as nifedipine, which is a calcium channel blocker.

All right, time for quiz. I have three questions for you. First question is a true, false question. Estrogen is contraindicated for a patient who smokes or who has hypertension. The answer is true. Another contraindication is if the patient has an increased risk for blood clots or embolic events. Question number two, what key teaching do you need to provide a patient who is receiving injectable medroxyprogesterone? The answer is, you need to teach that patient to increase their intake of calcium and vitamin D in order to prevent that key side effect of bone loss with this medication. Question number three, a mom receiving oxytocin is having contractions every two minutes that are 60 seconds in duration. Is that cause for concern, yes or no? The answer is no. So it is normal to have contractions that are 60 to 90 seconds in duration, and that occur every two to three minutes.

Okay, that's it for this video. I hope you enjoyed that quiz. If you struggled with any of the answers, then definitely go back and check the flashcards and study what those a little bit longer or re-watch the video, and I'll see you with more reproductive medications in my next video. Next, we have our uterine stimulants, so medications to know include oxytocin, as well as methylergonovine [laughter]. It'd be a miracle if I can get through this video and say methylergonovine, ergonovine. Okay, I got this. Methylergonovine, ergonovine, ergonovine, methylergonovine, methylergonovine, methylergonovine. If I say enough times, I figure it out. Okay, here we go.


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