Addis G J, Barclay J, Chang E M
Eur J Clin Pharmacol. 1979 Sep;16(2):97-100. doi: 10.1007/BF00563114.
This paper reports a study of the bronchodilator effects of doses of the beta 2 agonist fenoterol and the muscarinic blocker ipratropium suitable for administering in combination as a standard dose of two discharges from a single metered-dose pressurised aerosol. In 12 middle-aged bronchitics who had already been shown to respond to both types of drug the combination was almost always a little (6% on average) more effective than either drug singly. It is possible that an equal or better effect could have been obtained if fenoterol or perhaps ipratropium had been given alone in an individually determined maximally effective dose.