Effect of chronic theophylline therapy on brain blood flow and function in adult asthmatics

The impact of theophylline therapy on neuropsychological (NP) function in adult asthmatics is unclear. Additionally, whether the previously demonstrated acute reduction in cerebral blood flow (CBF) persists with continued administration of theophylline, or whether accommodation develops, has not been previously reported. We examined the effects of chronic theophylline administration on CBF and NP function in adults with mild to moderate asthma. Sixty adult patients with mild to moderate asthma were entered into this double-blind, placebo-controlled, crossover, random sequence study. Subjects received theophylline or placebo for 6 wk interposed with a 2-wk washout period. At the conclusion of Week 1 and Week 6 of each drug phase, patients received NP testing, and CBF was determined using the 133Xenon washout method. Forty-three patients completed the study. Theophylline administration was associated with small (6%), but statistically significant, reductions in CBF after both 1 and 6 wk of treatment. No differences consequent to theophylline administration were observed in any of the tests of NP function after 1 or 6 wk of therapy. While CBF was decreased after theophylline, the changes were small compared with previously reported decrements in CBF immediately after theophylline administration.