Theophylline plus hydroxyzine versus theophylline monohydrate in the treatment of asthma

The efficacy of 281.7 mg of theophylline monohydrate and a combination of theophylline (240 mg) + hydroxyzine (7.5 mg) were compared in a double-blind, crossover, placebo-controlled study in 15 patients with chronic reversible bronchial asthma. The patients took the drugs tested at 7.00 a.m., 3.00 p.m. and 10.00 p.m. During the 3-day trial period, the patients measured their peak expiratory flow (PEF) values every day at 7.00 a.m., 10.00 a.m. and 10.00 p.m., and during the last trial day, theophylline serum levels were also determined. Use of theophylline monohydrate resulted in slightly steadier serum theophylline levels than with theophylline + hydroxyzine and morning levels of theophylline were significantly higher (p less than 0.01) during the former treatment. Despite this, only the theophylline + hydroxyzine combination had a significant effect (p less than 0.05 at 7.00 a.m., p less than 0.01 at 10.00 a.m. and 10.00 p.m.) on PEF values at each time of measurement. There was a significant difference (p less than 0.05) in PEF values at 10.00 a.m. between the trial preparations in favour of the theophylline + hydroxyzine combination. Theophylline + hydroxyzine significantly decreased (p less than 0.05) nocturnal dyspnoea and most patients preferred this preparation. The differences in side effects were not statistically significant. The addition of hydroxyzine to theophylline increases the clinical efficacy of the latter.