Double-blind crossover study of carbuterol and salbutamol in bronchial asthma

A double-blind crossover comparative study between carbuterol 3 mg thrice daily, carbuterol 2 mg thrice daily and salbutamol 4 mg thrice daily by the oral route was conducted in thirty patients suffering from bronchial asthma, selected at random, with more than 20% reduction in airway obstruction following isoprenaline inhalation. Each patient received all three drugs consecutively, each for 6 days, with a wash-out period in-between. The present study established a relative superiority of carbuterol 3 mg thrice daily over carbuterol 2 mg and salbutamol 4 mg thrice daily as evidenced by a higher percentage of subjective improvement (78.8%), preference shown by more cases (17/27), and need of additional drugs in a minimum number of cases (6/27), and significant improvement in FEV1 and MMEFR (p less than 0.05). Salbutamol is known to produce tachycardia and a rise in blood pressure. There were no adverse side-effects on the cardiovascular system but unlike salbutamol, carbuterol produced a fall in pulse rate and blood pressure which should make carbuterol more acceptable to patients, especially on prolonged usage. There was an absence of significant side-effects on the haemopoietic system and kidneys; other side-effects observed with all three types of treatment were of a minor nature and did not necessitate withdrawal of the drug. Thus, carbuterol is an effective and safe selective beta 2-adrenergic stimulant, is relatively free from side-effects, and has a sustained bronchodilator effect, an advantage in therapeutic application, and is, as a result, a new effective drug in the management of bronchial asthma.