Continuous treatment of asthmatic patients with enprofylline and theophylline.

Twenty-five asthmatic outpatients were treated for 3 one-week periods with either enprofylline slowly eroding 300 mg tablets t.i.d., theophylline 300 mg tablets (Theo-Dur) t.i.d., or placebo in a double-blind, cross-over, randomized trial. Sixteen patients were able to complete 2 or 3 one-week periods. Evaluation of bronchodilating properties by home recordings of peak expiratory flow (PEF) and side effects suggested that enprofylline was an effective antiasthmatic xanthine derivative for continuous treatment, as it improved mean morning PEF significantly. Continuous treatment with the 2 xanthine derivatives resulted in mean steady state plasma levels within therapeutic range for theophylline, and 3-4 times lower mean plasma levels for enprofylline. Enprofylline induced headache in 13 of 16 patients, theophylline in 9 of 19 patients, and placebo in 2 of 18 patients. No serious side effects were seen.