The effectiveness of an antitussive beta 2 sympathomimetic combination, such as dextromethorphan and salbutamol combination were compared with dextromethorphan, which is a plain antitussive and a placebo in a double-blind clinical trial in almost 108 out-patients who had cough and is associated with acute respiratory infection.

The result of the trial showed that the dextromethorphan-salbutamol combination is superior to plain dextromethorphan or placebo in suppressing the cough at night. A spontaneous improvement was observed in all treatment groups in the 4-day treatment period. There were no significant differences between the treatments as shown in the symptom scores for the frequency of cough and its severity during the day, the quantity of sputum or easy expectoration. Also, a significant improvement was observed in cough during the day in all treatment groups.

The results of the trial advise that the use of antitussives is generally not necessary and the only indication could be symptomatic relief, especially at night. An antitussive such as dextromethorphan combined with a beta 2-sympathomimetic could be the most effective treatment in cough of acute respiratory infection.

Source: Eur J Respir Dis. 1986 Aug;69(2):95-9.