Severe cases: Determination of acid-base balance, blood sugar and electrolytes, particularly serum potassium levels. Monitoring of heart rate and rhythm and blood pressure. Metabolic changes should be corrected. A cardioselective beta-blocker (e.g. metoprolol) is recommended for the treatment of arrhythmias causing haemodynamic deterioration. The beta-blocker should be used with care because of the possibility of inducing bronchoconstriction: use with caution in patients with a history of bronchospasm. If the beta2-mediated reduction in peripheral vascular resistance significantly contributes to the fall in blood pressure, a volume expander should be given.. Bronchodilation. Terbutaline is a selective beta 2-adrenergic agonist recommended for the relief of bronchospasm in bronchial asthma and other bronchopulmonary disorders in which bronchospasm is a complicating factor.. Bricanyl® [Amp] is a bronchodilator, prescribed for asthma, bronchitis and emphysema. It works by relaxing and opening the airways that cause easy breathing..