Pharmacology of Tocolytic agents

Question 1

What are tocolytic agents?

Answer 1

Drugs designed to inhibit contractions of myometrial smooth muscle cells.
Drugs that decrease uterine contractility

Question 2

What are the aim of tocolysis?

Answer 2

To stop uterine contractions
To prevent preterm pregnancy
To prevent perinatal morbidity and mortality related to associated with preterm birth.

Question 3

Commonly used tocolytic medications include?

Answer 3

1. β 2 agonists: Terbutaline, retodrine
2. calcium channel blockers: Nifedipine, nicardipine
3. NSAIDs: Indomethacin, sulindac , ibuprofen, aspirin
4. magnesium sulfate.

Question 4

What is preterm labor?

Answer 4

which refers to when a baby is born too early before 37 weeks of pregnancy

Question 5

Tocolytics are considered for people with confirmed preterm labor between how many week gestation age?

Answer 5

24 and 34 weeks of gestation age

Question 6

Tocolytics are considered for people with confirmed preterm labor between how many week gestation age?

Answer 6

24 and 34 weeks of gestation age
and used in conjunction with other therapies that may include corticosteroids administration, fetus neuroprotection, and safe transfer to facilities.

Question 7

Name Beta 2 agonist that can be used as tocolytic agents?

Answer 7

Terbutaline
Isoxsurpin
Ritodrine
Fenoterol
Salbutamol

Question 8

What is MOA of beta 2 agonist as tocolysis agent?

Answer 8

Is through beta 2 receptor stimulation, causing smooth muscle relaxation.

Question 9

Why beta 2 agonist should not be used for more than 48 hours? as they can lead to increased risk

Answer 9

as they can lead to increased risk to the mother.

Question 10

When to use beta 2 agonist?

Answer 10

Used in uncomplicated premature labor between 24th to 33rd weeks of
gestation.

Question 11

What is FDA recommendation for terbutaline used?

Answer 11

Off label use, FDA has advised that injectable terbutaline should only be used in urgent situations, and that the oral form of the drug should never be used.

Question 12

Contraindications: of terbutaline?

Answer 12

• Pregnant diabetic or pregnancy induced diabetic patients.
• poorly controlled diabetes mellitus,
• hyperthyroidism,
• Patients taking beta blockers.

Question 13

Side effects of terbutaline?

Answer 13

Mother: Tachycardia , palpitations, hypotension, dyspnea, chest pain, hypokalemia, hyperglycemia, lipolysis, pulmonary edema, myocardial ischemia.

Fetus: Fetal tachycardia, hyperinsulinemia, hypoglycemia

Question 14

Contraindications: of Ritodrine.

Answer 14

Poorly controlled thyroid disease, hypertension, and diabetes

Question 15

Contraindications of foneterol

Answer 15

Diabetes, tachyarrhythmia, hypertrophic obstructive cardiomyopathy, hypersensitivity to fenoterol

Question 16

Name Ca channel blocker used as tocolytic agent.

Answer 16

Nifedipine and nicardipine

Question 17

Mechanism of action CCB as tocolytic agent

Answer 17

• Block the influx of calcium ions, thereby reducing the intra cellular calcium, reduces the tone of myometrium and opposes the contraction.
• CCB has prominent smooth muscle relaxant action which is effective if used early enough.

Question 18

Side effects CCB?

Answer 18

Tachycardia, Flushing , headache, dizziness, nausea, transient
hypotension.
- Administration of calcium channel blockers should be used with care in patients with renal disease and hypotension.

Fetal: Calcium channel blockers have the fewest neonatal adverse effects
- Reduced placental perfusion may cause fetal hypoxia

Question 19

Why CCB should not be used concomitantly with magnesium sulfate?

Answer 19

use of calcium channel blockers and magnesium sulfate may result in
cardiovascular collapse

Question 20

Contraindications CCB?

Answer 20

Contraindications: Hypotension, preload dependent cardiac disease.

Question 21

What is Atosiban?

Answer 21

It is a peptide analogue of oxytocin , acts as an oxytocin receptor antagonist

Question 22

Effectiveness of Atosiban?

Answer 22

As effective as nifedipine and more effective than beta agonists.
- Fewer side effects than β 2 agonists

Question 23

Administration of Atosiban?

Answer 23

Atosiban is a modified form of oxytocin that is administered by intravenous infusion for 2 48 hours.