Enprofylline and theophylline slow-eroding tablets in the treatment of asthma: a comparison.

Fifteen asthmatic outpatients were randomly treated during two periods of 14 days each with sustained-release preparations of either enprofylline (3-propyl-xanthine) or theophylline (Theo-Dur) in a double-blind crossover study. After 4 days of treatment the mean daily doses of enprofylline and theophylline, which were 14.1 and 16.2 mg/kg/day, produced mean plasma concentrations of 4.9 and 12.7 micrograms/ml, respectively. Taking into account all the parameters used to evaluate the antiasthmatic effects, the peak expiratory flow, the number of puffs used from a beta-agonist aerosol, the asthma symptom score and the patients' preferred period, enprofylline was found to be better than theophylline. Enprofylline produced more headaches during the 1st week than theophylline did. However, during the 2nd week the score for headaches decreased to the same level as in the theophylline treatment group. Thus, enprofylline and theophylline seem to have comparable bronchodilator properties and side-effects in the long-term treatment of asthma.