Overview
DESCRIPTION Terbutaline sulfate USP is a beta-adrenergic agonist bronchodilator available as tablets of 2.5 mg (2.05 mg of the free base) and 5 mg (4.1 mg of the free base) for oral administration. Terbutaline sulfate is ±-α-[( tert –butylamino) methyl]-3,5-dihydroxybenzyl alcohol sulfate (2:1) (salt).
Mechanism of Action
CLINICAL PHARMACOLOGY In vitro and in vivo pharmacologic studies have demonstrated that terbutaline exerts a preferential effect on beta 2 -adrenergic receptors. While it is recognized that beta 2 -adrenergic receptors are the predominant receptors in bronchial smooth muscle, data indicate that there is a population of beta 2 -receptors in the human heart, existing in a concentration between 10% to 50%. The precise function of these receptors has not been established (see WARNINGS ). In controlled clinical studies in patients given terbutaline sulfate orally, proportionally greater changes occurred in pulmonary function parameters than in heart rate or blood pressure.
Indications
- INDICATIONS AND USAGE Terbutaline sulfate is indicated for the prevention and reversal of bronchospasm in patients 12 years of age and older with asthma and reversible bronchospasm associated with bronchitis and emphysema.
Common Doses
- 5 mg
- 2.5 mg
- 15 mg
- 7.5 mg
Dosage
DOSAGE AND ADMINISTRATION Adults The usual oral dose of terbutaline sulfate for adults is 5 mg administered at approximately six-hour intervals, three times daily, during the hours the patient is usually awake. If side effects are particularly disturbing, the dose may be reduced to 2.5 mg three times daily, and still provide a clinically significant improvement in pulmonary function. The total dose within 24 hours should not exceed 15 mg. Children Terbutaline sulfate is not recommended for use in children below the age of 12 years. A dosage of 2.
Black Box Warning
WARNING: TOCOLYSIS Oral terbutaline sulfate has not been approved and should not be used for acute or maintenance tocolysis. In particular, terbutaline sulfate should not be used for maintenance tocolysis in the outpatient or home setting. Serious adverse reactions, including death, have been reported after administration of terbutaline sulfate to pregnant women. In the mother, these adverse reactions include increased heart rate, transient hyperglycemia, hypokalemia, cardiac arrhythmias, pulmonary edema and myocardial ischemia.
Contraindications
- CONTRAINDICATIONS 1. Tocolysis Oral terbutaline sulfate has not been approved and should not be used for acute or maintenance tocolysis. [see Boxed Warning: Tocolysis . ] 2. Hypersensitivity Terbutaline sulfate is contraindicated in patients known to be hypersensitive to sympathomimetic amines or any component of this drug product.
Side Effects
- ADVERSE REACTIONS Adverse reactions observed with terbutaline sulfate are similar to those commonly seen with other sympathomimetic amines. All of these reactions are generally transient in nature and usually do not require treatment. The frequency of these side effects appears to diminish with continued therapy. The following table lists the adverse reactions seen in 199 patients treated with terbutaline sulfate tablets during six double-blind crossover studies and four double-blind parallel studies (short- and long-term) performed in the United States.
Interactions
- Drug Interactions The concomitant use of terbutaline sulfate 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.