Classifications: autonomic nervous system agent; beta-adrenergic agonist
Pregnancy Category: C
10 mg/mL, 15 mg/mL, 0.3 mg/mL injection
Preferentially stimulates beta2-receptors in uterine smooth muscle, reducing intensity and frequency of uterine contractions and lengthening gestation period. (Actions may be eliminated by beta-adrenergic antagonists.) Transitory cardiovascular effects include increased cardiac output, increased maternal and fetal heart rates, and widening of maternal pulse pressure (beta1 stimulation).
Beta2- adrenergic agonist clinically effective in preventing or delaying preterm labor (tocolytic effect). Uterine contractions will decrease in frequency and intensity during treatment.
To manage premature labor in selected patients.
Mild to moderate preeclampsia or eclampsia, intrauterine infection, cervix dilated 4 cm or more (in a single pregnancy); pregnancy (category C); hypertension; diabetes mellitus; prior to 20th wk or after 36th wk of pregnancy or if continuation of pregnancy would be hazardous to mother and fetus (e.g., antepartum hemorrhage, eclampsia, intrauterine fetal death, maternal cardiac disease, pulmonary hypertension, maternal hyperthyroidism, severe diabetes mellitus). Also hypovolemia, cardiac arrhythmias associated with tachycardia or digitalis intoxication, uncontrolled hypertension; thyrotoxicosis; bronchial asthma being treated with betamimetics or steroids; lactation.
Concomitant use of potassium-depleting diuretics, cardiac disease.
Adult: PO Start 30 min before terminating infusion, 10 mg q2h for first 24 h, then 1020 mg q46h (max: 120 mg/d) IV 50100 mcg/min, may increase by 50 mcg/min q10min until uterine relaxation is achieved, may continue for up to 12 h after contractions have ceased
Note: IV solution should be clear. Discard if cloudy or a precipitate is present.
PREPARE: IV Infusion: Add 150 mg ritodrine to 500 mL D5W or NS solution to yield 0.3 mg/mL (300 mcg/mL).
ADMINISTER: IV Infusion: Begin at 50 mcg/min and increase by 50 mcg q10 min until desired response. Monitor IV infusion flow rate to prevent circulation overload. Use a microdrip and infusion pump.
Ritodrine (IV route) may produce an increase in serum levels of glucose, insulin, and free fatty acids, and a decrease in serum potassium. It temporarily elevates results of glucose tolerance test.
Assessment & Drug Effects
Patient & Family Education