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Terbutaline (Terbutaline Sulfate) - Warnings and Precautions

 
 



WARNINGS

Deterioration of Asthma

Asthma may deteriorate acutely over a period of hours or chronically over several days or longer. If the patient needs more doses of terbutaline sulfate tablets, USP than usual, this may be a marker of destabilization of asthma and requires reevaluation of the patient and the treatment regimen, giving special consideration to the possible need for anti-inflammatory treatment, e.g., corticosteroids.

Use of Anti-Inflammatory Agents

The use of beta-adrenergic agonist bronchodilators alone may not be adequate to control asthma in many patients. Early consideration should be given to adding anti-inflammatory agents, e.g., corticosteroids.

Cardiovascular Effects

Terbutaline sulfate tablets, USP, like all other beta-adrenergic agonists, can produce a clinically significant cardiovascular effect in some patients as measured by pulse rate, blood pressure, and/or symptoms. Although such effects are uncommon after administration of terbutaline sulfate tablets, USP at recommended doses, if they occur, the drug may need to be discontinued. In addition, beta-agonists have been reported to produce electrocardiogram (ECG) changes, such as flattening of the T wave, prolongation of the QTc interval, and ST segment depression. The clinical significance of these findings in unknown. Therefore, terbutaline sulfate tablets, USP, like all sympathomimetic amines, should be used with caution in patients with cardiovascular disorders, especially coronary insufficiency, cardiac arrhythmias, and hypertension.

Seizures

There have been rare reports of seizures in patients receiving terbutaline; seizures did not recur in these patients after the drug was discontinued.

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; hyperthyroidism; diabetes mellitus; hypersensitivity to sympathomimetic amines; and 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 exacerbation 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 sulfate have been reported to aggravate preexisting diabetes and ketoacidosis.

Information for Patients

The action of terbutaline sulfate tablets, USP should last up to 6 hours or longer. Terbutaline sulfate tablets, USP should not be used more frequently than recommended. Do not increase the dose or frequency of terbutaline sulfate tablets, USP without consulting your physician. If you find that treatment with terbutaline sulfate tablets, USP becomes less effective for symptomatic relief, your symptoms become worse, and/or you need to use the product more frequently than usual, you should seek medical attention immediately. While taking terbutaline sulfate tablets, USP, other inhaled drugs and asthma medications should be taken only as directed by your physician. Common adverse effects include palpitations, chest pain, rapid heart rate, tremor or nervousness. If you are pregnant or nursing, contact your physician about use of terbutaline sulfate tablets, USP. Effective and safe use of terbutaline sulfate tablets, USP includes an understanding of the way that it should be administered.

Drug Interactions

The concomitant use of terbutaline sulfate tablets, USP with other sympathomimetic agents is not recommended, since the combined effect on the cardiovascular system may be deleterious to the patient. However, this does not preclude the use of an aerosol bronchodilator of the adrenergic-stimulant type for the relief of an acute bronchospasm in patients receiving chronic oral therapy with terbutaline sulfate tablets, USP.

Monoamine Oxidase Inhibitors and Tricyclic Antidepressants

Terbutaline sulfate should be administered with extreme caution to patients being treated with monoamine oxidase inhibitors or tricyclic antidepressants, or within 2 weeks of discontinuation of such agents, since the action of terbutaline sulfate on the vascular system may be potentiated.

Beta-Blockers

Beta-adrenergic receptor blocking agents not only block the pulmonary effect of beta-agonists, such as terbutaline sulfate tablets, USP, but may produce severe bronchospasm in asthmatic patients. Therefore, patients with asthma should not normally be treated with beta-blockers. However, under certain circumstances, e.g., as prophylaxis after myocardial infarction, there may be no acceptable alternatives to the use of beta-adrenergic blocking agents in patients with asthma. In this setting, cardioselective beta-blockers could be considered, although they should be administered with caution.

Diuretics

The ECG changes and/or hypokalemia that may result from the administration of non-potassium sparing diuretics (such as loop or thiazide diuretics) can be acutely worsened by beta-agonists, especially when the recommended dose of the beta-agonist is exceeded. Although the clinical significance of these effects is not known, caution is advised in the coadministration of beta-agonists with non-potassium sparing diuretics.

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 25 times the maximum recommended daily oral 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 55 times the maximum recommended daily oral 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 25 times the maximum recommended daily oral dose for adults on a mg/m2 basis).

Teratogenic Effects

Pregnancy Category B

A reproduction study in Sprague-Dawley rats revealed terbutaline sulfate was not teratogenic when administered at oral doses of 50 mg/kg (approximately 25 times the maximum recommended daily oral dose for adults on a mg/m2 basis). A reproduction study in New Zealand white rabbits revealed terbutaline sulfate was not teratogenic when administered at oral doses up to 50 mg/kg (approximately 55 times the maximum recommended daily oral 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, this drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. (see PRECAUTIONS, Tocolysis).

Use in Labor and Delivery

Because of the potential for beta-agonist interference with uterine contractility, use of terbutaline sulfate tablets, USP 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 sulfate tablets, USP should be used during nursing only if the potential benefit justifies the possible risk to the newborn.

Pediatric Use

Terbutaline sulfate tablets, USP are not recommended for patients under the age of 12 years because of insufficient clinical data to establish safety and effectiveness (see DOSAGE AND ADMINISTRATION).

Page last updated: 2010-08-16

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