Table of Contents
What are Tocolytics?
Tocolytics are a type of medication that can help delay or stop preterm labor, which is when a baby is born before 37 weeks of pregnancy. Preterm birth can cause serious health problems for the baby, such as breathing difficulties, vision loss, cerebral palsy, and developmental delays. Therefore, tocolytics can be useful in giving the baby more time to grow and develop in the womb, and allowing the mother to receive other treatments that can improve the baby’s chances of survival and well-being.
Tocolytics Examples
There are different kinds of tocolytics, each with their own mechanism of action, benefits, and side effects. Some of the most commonly used tocolytics are:
- β 2 agonists, such as terbutaline, which relax the uterine muscles by stimulating the β 2 receptors on them. These drugs can also affect the heart and lungs, causing increased heart rate, palpitations, chest pain, tremors, and anxiety. They are not recommended for long-term use or for women with heart problems or diabetes.
- Calcium channel blockers, such as nifedipine, which prevent calcium from entering the uterine muscle cells, thus reducing their contraction. These drugs can also lower blood pressure and cause headaches, flushing, dizziness, and nausea. They are generally well-tolerated and effective in delaying preterm labor.
- NSAIDs, such as indomethacin, inhibit the production of prostaglandins, which are hormones that stimulate uterine contractions. These drugs can also reduce blood flow to the kidneys and the placenta, causing decreased urine output, fluid retention, bleeding problems, and fetal complications such as premature closure of the ductus arteriosus (a blood vessel that connects the pulmonary artery and the aorta in the fetus). They are usually used for short-term treatment and are avoided after 32 weeks of gestation.
- Magnesium sulfate, which acts as a muscle relaxant by interfering with calcium uptake in the uterine muscle cells. This drug can also cause sedation, weakness, flushing, sweating, nausea, vomiting, and blurred vision. It can also affect the nervous system of the mother and the baby, causing respiratory depression, low blood pressure, low heart rate, low calcium levels, and bone problems. It is usually given intravenously in a hospital setting and monitored closely.
Tocolytics are not a cure for preterm labor, but rather a temporary measure to postpone delivery for a few days or weeks. They are not effective in all cases and may have serious side effects for both the mother and the baby. Therefore, they should only be used when the benefits outweigh the risks and when there is a clear indication for delaying birth.
Indications for Tocolytics
Some of the indications for using tocolytics are:
- When preterm labor occurs between 24 and 34 weeks of gestation
- When there is evidence of fetal distress or infection
- When there is a need to transfer the mother to a specialized facility or administer corticosteroids to enhance fetal lung maturity
- When there is a chance of reversing or treating the underlying cause of preterm labor
Contraindications for Tocolytics
Tocolytics are not indicated in cases where:
- The pregnancy is beyond 34 weeks of gestation
- There is severe preeclampsia or eclampsia (a condition characterized by high blood pressure and proteinuria in pregnancy)
- There is placental abruption (a condition where the placenta separates from the uterine wall)
- There is fetal death or severe malformation
- There is chorioamnionitis (a bacterial infection of the amniotic fluid and membranes)
- There is active vaginal bleeding or rupture of membranes
- There is a maternal allergy or intolerance to the tocolytic drug
Tocolytics are an important tool in managing preterm labor and improving neonatal outcomes. However, they are not without risks and limitations. Therefore, they should be used judiciously and under close medical supervision. If you have any questions or concerns about tocolytics or preterm labor, please consult your doctor or healthcare provider.
Short & Long Term Nursing Care While Administering Tocolytics
Nursing care for tocolytics involves assessing the mother and the baby, administering the medication, monitoring for side effects and complications, and educating the mother about the purpose and risks of the treatment. Some of the general nursing care for tocolytics are:
- Assessing the contractions, cervical dilation and effacement, fetal heart rate and variability, and signs of fetal distress or infection.
- Administering the medication according to the protocol or order set, using the appropriate route and dosage.
- Monitoring the vital signs, oxygen saturation, weight, heart and lung sounds, urine output and input, and blood tests of the mother.
- Monitoring for adverse reactions such as hypotension, tachycardia, arrhythmias, palpitations, chest pain, tremors, anxiety, nausea, vomiting, headache, flushing, dizziness, bleeding problems, fluid retention, pulmonary edema, respiratory depression, altered level of consciousness, and decreased deep tendon reflexes.
- Notifying the obstetrician or midwife if there are any abnormal findings or changes in the maternal or fetal condition.
- Preparing for intrauterine resuscitation if needed, such as giving intravenous fluid bolus, positioning the mother laterally, and administering oxygen.
- Educating the mother about the purpose of the medication, the potential side effects to report, and the required nursing monitoring.
The specific nursing care for tocolytics may vary depending on the type of medication used. There are different kinds of tocolytics, each with their own mechanism of action, benefits, and side effects. Some of the most commonly used tocolytics are:
- β 2 agonists, such as terbutaline (Brethine), relax the uterine muscles by stimulating the β 2 receptors on them. These drugs can also affect the heart and lungs, causing increased heart rate, palpitations, chest pain, tremors, and anxiety. They are not recommended for long-term use or for women with heart problems or diabetes.
- Calcium channel blockers, such as nifedipine (Procardia), which prevent calcium from entering the uterine muscle cells, thus reducing their contraction. These drugs can also lower blood pressure and cause headaches, flushing, dizziness, and nausea. They are generally well-tolerated and effective in delaying preterm labor.
- NSAIDs, such as indomethacin (Indocin), inhibit the production of prostaglandins, which are hormones that stimulate uterine contractions. These drugs can also reduce blood flow to the kidneys and the placenta, causing decreased urine output, fluid retention, bleeding problems, and fetal complications such as premature closure of the ductus arteriosus (a blood vessel that connects the pulmonary artery and the aorta in the fetus). They are usually used for short-term treatment and are avoided after 32 weeks of gestation.
- Magnesium sulfate, which acts as a muscle relaxant by interfering with calcium uptake in the uterine muscle cells. This drug can also cause sedation, weakness, flushing, sweating, nausea, vomiting, and blurred vision. It can also affect the nervous system of the mother and the baby, causing respiratory depression, low blood pressure, low heart rate, low calcium levels, and bone problems. It is usually given intravenously in a hospital setting and monitored closely.
Some of the specific nursing care for each type of tocolytic:
- For β 2 agonists,
- Assess the maternal heart rate and the fetal heart rate pattern before and after each dose.
- Hold dose and notify obstetrician or midwife for fetal heart rate > 180 beats per minute, indeterminate or abnormal fetal heart rate, maternal heart rate > 120 beats per minute, palpitations, respirations > 30 breaths per minute, pulmonary crackles, or oxygen saturation < 95%.
- For calcium channel blockers,
- Closely monitor for hypotension and give fluids or other medications to increase blood pressure if needed.
- Do not use magnesium sulfate unless necessary because it will lower blood pressure further.
- For NSAIDs,
- Monitor for signs of bleeding such as bruising, petechiae, hematuria, or melena.
- Monitor for signs of oligohydramnios such as decreased fetal movement, decreased amniotic fluid index, or fetal compression.
- Monitor for signs of premature ductus arteriosus closure such as fetal heart murmur, increased pulmonary artery pressure, or decreased aortic pressure.
- For magnesium sulfate,
- Administer by infusion pump and have two nurses check dosage and infusion rate.
- Monitor renal function such as baseline serum creatinine, indwelling urinary catheter, and urine output and input.
- Monitor deep tendon reflexes and have calcium gluconate (antidote) readily available.
- Notify the obstetrician or midwife for urine output < 30 mL per hour, absent deep tendon reflexes, respiratory rate < 12 breaths per minute, oxygen saturation < 95%, shortness of breath, adventitious breath sounds, decreased level of consciousness, or magnesium level > 8 mg per dL.