Terbutaline

INTRODUCTION

Indications

Management of reversible airway disease due to asthma or COPD; inhalation and SC used for short-term control and oral agent as long-term control. Unlabeled Use: Management of preterm labor (tocolytic).

Action

Results in the accumulation of cyclic adenosine monophosphate (cAMP) at beta-adrenergic receptors. Produces bronchodilation. Inhibits the release of mediators of immediate hypersensitivity reactions from mast cells. Relatively selective for beta₂ (pulmonary)–adrenergic receptor sites, with less effect on beta₁ (cardiac)–adrenergic receptors. Therapeutic Effects: Bronchodilation.

Adverse Reactions/Side Effects

CNS: nervousness, restlessness, tremor, headache, insomnia. Resp: PARADOXICAL BRONCHOSPASM (EXCESSIVE USE OF INHALERS). CV: angina, arrhythmias, hypertension, tachycardia. GI: nausea, vomiting. Endo: hyperglycemia.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Watch for signs of paradoxical bronchospasm (wheezing, cough, dyspnea, tightness in chest and throat), especially at higher or excessive doses. If condition occurs, advise patient to withhold medication and notify physician or other health care professional immediately.

• Assess pulmonary function at rest and during exercise (See Appendices I, J, K) to document effectiveness of medication in controlling bronchospasm.

• Assess blood pressure (BP) periodically and compare to normal values (See Appendix F). Report a sustained increase in BP (hypertension) to the physician.

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report a rapid heart rate (tachycardia) or signs of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Be alert for signs of hyperglycemia, including confusion, drowsiness, flushed/dry skin, fruit-like breath odor, rapid/deep breathing, polyuria, loss of appetite, and unusual thirst. Patients with diabetes mellitus should check blood glucose levels frequently.

• Monitor and report signs of CNS toxicity, including nervousness, restlessness, tremor, or hyperactivity. Sustained or severe CNS signs may indicate overdose or excessive use of this drug.

Interventions

• When implementing airway clearance techniques or respiratory muscle training, attempt to intervene when the airway is maximally bronchodilated. Peak responses typically occur 1–2 hr after inhalation, 2–3 hr after oral administration, and 0.5-1 hr after SC injection.

• Because of the risk of cardiovascular stimulation, use caution during aerobic exercise and endurance conditioning. Cardiac effects should be minimal at lower oral doses or occasional inhaled use. Cardiovascular effects such as arrhythmias, angina pectoris, or increased BP may occur at higher doses or during excessive use, and are caused by inadvertent stimulation of beta receptors on the heart.

Patient/Client-Related Instruction

• Advise patient to not exceed the recommended dose or frequency of inhalations. Contact physician immediately if bronchospasm is not relieved by medication or is accompanied by diaphoresis, dizziness, or other symptoms.

• Counsel patient ...