PRECAUTIONS
Tocolysis
Terbutaline sulfate has not been approved and should not be used for tocolysis. Serious adverse reactions may occur after administration of terbutaline sulfate to women in labor. In the mother, these include increased heart rate, transient hyperglycemia, hypokalemia, cardiac arrhythmias, pulmonary edema, and myocardial ischemia. Increased fetal heart rate and neonatal hypoglycemia may occur as a result of maternal administration.
General
Terbutaline, as with all sympathomimetic amines, should be used with caution in patients with cardiovascular disorders, including ischemic heart disease, hypertension, and cardiac arrhythmias; in patients with hyperthyroidism or diabetes mellitus; and in patients who are unusually responsive to sympathomimetic amines or who have convulsive disorders. Significant changes in systolic and diastolic blood pressure have been seen and could be expected to occur in some patients after use of any beta-adrenergic bronchodilator.
Immediate hypersensitivity reactions and exacerbations of bronchospasm have been reported after terbutaline administration.
Beta-adrenergic agonist medications may produce significant hypokalemia in some patients, possibly through intracellular shunting, which has the potential to produce adverse cardiovascular effects. The decrease is usually transient, not requiring supplementation.
Large doses of intravenous terbutaline have been reported to aggravate pre-existing diabetes mellitus and ketoacidosis.
Carcinogenesis, Mutagenesis, Impairment of Fertility
In a 2-year study in Sprague-Dawley rats, terbutaline sulfate caused a significant
and dose-related increase in the incidence of benign leiomyomas of the mesovarium
at dietary doses of 50 mg/kg and above (approximately 810 times the maximum
recommended daily subcutaneous (sc) dose for adults on a mg/m2 basis).
In a 21-month study in CD-1 mice, terbutaline sulfate showed no evidence of
tumorigenicity at dietary doses up to 200 mg/kg (approximately 1,600 times the
maximum recommended daily sc dose for adults on a mg/m2 basis). The
mutagenicity potential of terbutaline sulfate has not been determined.
Reproduction studies in rats using terbutaline sulfate demonstrated no impairment
of fertility at oral doses up to 50 mg/kg (approximately 810 times the maximum
recommended daily sc dose for adults on a mg/m2 basis).
Pregnancy
Teratogenic Effects: Pregnancy Category B
A reproduction study in Sprague-Dawley rats revealed terbutaline sulfate was
not teratogenic when administered orally at doses up to 50 mg/kg (approximately
810 times the maximum recommended daily sc dose for adults on a mg/m2
basis). A reproduction study in New Zealand white rabbits revealed terbutaline
sulfate was not teratogenic when administered orally at doses up to 50 mg/kg
(approximately 1,600 times the maximum recommended daily sc dose for adults
on a mg/m2 basis).
There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human responses, terbutaline should be used during pregnancy only if the potential benefits justify the potential risk to the fetus.
Use In Labor and Delivery
Because of the potential for beta-agonist interference with uterine contractility, use of terbutaline for relief of bronchospasm during labor should be restricted to those patients in whom the benefits clearly outweigh the risk.
Terbutaline crosses the placenta. After single dose IV administration of terbutaline to 22 women in late pregnancy who were delivered by elective Cesarean section due to clinical reasons, umbilical blood levels of terbutaline were found to range from 11% to 48% of the maternal blood levels.
Nursing Mothers
It is not known whether this drug is excreted in human milk. Therefore, terbutaline should be used during nursing only if the potential benefit justifies the possible risk to the newborn.
Pediatric Use
Terbutaline is not recommended for patients under the age of 12 years because of insufficient clinical data to establish safety and effectiveness.
Geriatric Use
Clinical studies of terbutaline sulfate injection did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.