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metaproterenol (met-a-proe-ter-e-nole)



Therapeutic: bronchodilators

Pharmacologic: adrenergics


Treatment/prevention of bronchospasm due to reversible airway disease (a short-term control agent).


Results in the accumulation of cyclic adenosine monophosphate (cAMP) at beta2-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.


Examination and Evaluation

  • Watch for signs of paradoxical bronchospasm, including wheezing, cough, dyspnea, shortness of breath, and tightness in chest and throat. These signs are more common at higher doses or during excessive use of the inhaler. 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 heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report any rhythm disturbances or symptoms of increased arrhythmias, including palpitations, chest pain, shortness of breath, fainting, and fatigue/weakness.

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

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

  • 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.


  • When implementing airway clearance techniques or respiratory muscle training, attempt to intervene when the airway is maximally bronchodilated. Peak responses typically occur about 1 hr after inhalation or oral administration.

  • Because of the risk of cardiovascular stimulation, use caution during aerobic exercise and endurance conditioning. Cardiac effects should be minimal at lower 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 on proper use of inhaler; observe use of this device whenever possible to ensure proper technique.

  • Instruct ...

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