Double-blind comparative trial of Nuelin Depot and TheoDur with adjusted dosage in asthmatic adults

Abstract

Equivalent doses of two sustained release preparations of theophylline, Nuelin Depot and TheoDur, were compared in a double blind, cross-over study. Twenty adult outpatients with COLD were given adjusted doses of the two preparations to reach a peak value of theophylline in steady state within the therapeutic range. The study consisted of two 14-day periods and airway function parametres, plasma concentrations, asthma symptoms, and side effects were recorded the last day in each period. In addition morning PEFR, use of beta 2 stimulant aerosol and number of nightly attacks were recorded daily. As judged from the peak-trough variation of 24.8 mumol for Nuelin Depot and 26.3 mumol/l for TheoDur as well as the tmax of 4.3 hours for Nuelin and 3.6 hours for TheoDur, both products produced a similar plasma profile. No statistically significant differences were found between the two preparations with respect to airway function parameters, relief of asthma symptoms, need for beta 2-stimulant aerosol or side effects. In conclusion these two sustained release preparations should be considered equivalent for practical use.