Tocolytics
Stacy Fernandez, MD/MPH Candidate 2011
tocolytics
Drugs that decrease uterine tone (BEMP)
Beta-2 agonists
Ethanol
Magnesium Sulfate
Methylxanthines
Potent (volatile) anesthetics (NO)
Objectives
Delay labor for 48 hrs to administer steroids
Transport mom and baby to facility able to provide
appropriate care
Prolong pregnancy with self limited conditions
(pyelonephritis, abdominal surgery, etc)
terbutaline and Ritodrine
Beta-2 agonists cause myometrium relaxation
MOA- Inc Adenyl Cyclase and cAMP
Side Effects
B1
B2
Side Effects
Contraindication
Inc HR, CO
Cardiac Disease
Inc Glu, Dec BP
Hyperthyroid
Pulmonary Edema Uncontrolled DM
Caution with
Dec K+
Bleedi
Arrythmias
Bleeding
Ethanol
give in 10% D5W
thought to inhibit oxytocin
associated with an increased risk of gastric aspiration
Magnesium
MOA- unknown, but may interfere with Ca at the plasma membrane voltage
gated channels, hyperpolarizing the cell
CNS depressant and a mild vasodilator
works at the NMJ (in the Blue Book)
Side Effects: flushing, diaphoresis, decreased fetal HR and variability
Contraindications: Myastenia Gravis, myocardial compromise
Indomethacin
Nonspecific COX inhibitor, prostaglandin synthetase
inhibitor
Prostaglandins increase myometrial gap junctions
that increase Ca through transmembrane influx and
from the sarcolemma
Side Effects: Primary Pulmonary Hypertension,
premature PDA closure, predispose to bleeding
(decreased Thromboxane A2)
increasing uterine tone
PGF2 alpha
Ergots
Oxytocin
Ketamine
Amide local anesthetics
Thank you!
Questions?