12.01 Tocolytics

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  1. Anti-contraction meds, labor suppressant
  2. Tokos = Greek word for childbirth
  3. Lytic = lysis = decline of disease/symptoms

Nursing Points


  1. Use: prevent preterm labor by suppressing uterine contractions
    1. Preterm = before 37 weeks
  2. If preterm labor cannot be stopped, tocolytics allow time for the administration of betamethasone to attempt to quickly increase lung maturity over 24-48 hours


  1. Assess contractions
    1. True labor v. false labor
  2. Fetal monitoring
    1. Assess for fetal distress

Therapeutic Management

  1. Follow your protocol/order set:
    1. Frequency of assessments
    2. Vitals
    3. Adverse reactions
    4. I&O
  2. Terbutaline (Brethine)
    1. Class: Beta 2 adrenergic-agonist
    2. MOA: Cause smooth muscle relaxation in uterus
    3. Nursing Implications
      1. Most adverse effects are cardiac related
        1. Maternal tachycardia
      2. Also causes bronchodilation
      3. See Autonomic Nervous System lesson in Pharmacology course
    4. Route
      1. IV, SubQ
  3. Nifedipine
    1. Class: Calcium channel blocker
    2. MOA: Disrupts calcium entry into the cell, which reduce smooth muscle contractions in uterus
    3. Nursing Implications
      1. Rapidly lowers BP, watch closely as you may need to give fluids or other meds to increase BP
      2. Don’t use with mag unless you really need to b/c it will lower BP further
    4. Route
      1. PO
      2. Multiple dosing options and no clear gold dosing standard
  4. Indomethacin
    1. Class: NSAID
    2. MOA: Inhibits prostaglandins, which cause uterine contractions
    3. Nursing Implications:
      1. Same bleeding precautions as other NSAIDs
      2. Don’t use if patient has peptic ulcers
      3. Should only be used if <32 weeks
      4. Can prematurely close fetus’ ductus arteriosus → assessment by ultrasound
      5. Can decrease fetal urine production → watch for oligohydramnios (deficiency of amniotic fluid)
    4. Route
      1. PO, rectal, vaginal
  5. Always monitor for potential adverse reactions and notify MD when noted

Nursing Concepts

  1. Pharmacology
  2. Safety
  3. Evidence based practice

Patient Education

  1. Thoroughly educate mother and support system about what to expect
  2. Medication purpose
  3. Side effects to notify about
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In this lesson I will discuss tocolytics with you and why they are used and what to watch for with each.

What is a tocolytic? This is a medication that stops contractions. So it is an anti-contraction meds or labor suppressant. And why in the world would we stop labor? Well preterm labor needs to be stopped as well as when the uterus is hyperstimulated, so contracting too much. Also when a breech patient comes for a version, for flipping the baby the provider will want to relax the uterus so we give a tocolytic. Now there is constant research going on with tocolytics so this is ever changing but we will talk about some of the main ones.

Let’s look at some options. Terbutaline and Nifedipine are the ones I see used most but this can vary by the facility. Terbutaline is going to be given IV or subcutaneous. The biggest side effect is maternal tachycardia. T and T. We typically would just continue to monitor the mother through this tachycardia. It is one of those benefit over risk things where giving her the terbutaline is more important unless she worsens or has other concerns. Nifedipine is given PO and the biggest side effect will be hypotension. Indomethacin is given either PO, rectal, or vaginal. This drug is an NSAID so a mother with peptic ulcers or bleeding problems should probably be given a different tocolytic. This drug puts the fetus at risk also. It can decrease the amount of urine the fetus produces so we need to watch for oligohydramnios and it can also cause the ductus arteriosus to close in the heart prior to birth. This is rare but ultrasounds should be done to detect if this has occurred but this can cause big problems for the baby.

We want to offer medication education. So things to educate the family on are what to expect. If she is given terbutaline for example we want her to know that she might feel her heart rate increase or with Nifedipine her blood pressure might drop so she might feel lightheaded. We also want her to know the medication purpose. Why are we are giving it? We need to stop the contractions. Also we want her to report any side effects. We will be really monitoring the patient but if she starts to not feel right or is having these side effects then we want to know so we can intervene if necessary.

Our concepts are pharmacology because we are talking about medications. Safety because we are looking out for the safety of the baby by stopping preterm labor and also safety of the mother with medication use and evidence based practice because research is continually being done about the best treatments for preterm labor and is ever evolving.

Alright so the important things for you to remember are here. Tocolytics are used to stop uterine contractions. So this would be in preterm labor or anytime we need to relax the uterus. So for example a version or a hyperstimulated uterus during labor. The most commonly used drugs are Terbutaline, Nifedipine, and Indomethacin. Our biggest side effects of terbutaline are tachycardia. Nifedipine is hypotension, and indomethacin is bleeding because it is a NSAID, oligohydramnios from a decrease in fetal urine and the ductus arteriosus closing prior to delivery, so this should only be used if less than 32 weeks gestation

Make sure you check out the resources attached to this lesson and review the side effects of each tocolytic. Now, go out and be your best selves today. And, as always, happy nursing.

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