Repeated dosing of Uniphyl tablets under fed and fasting conditions: comparison of serum theophylline levels, pulmonary function, and asthma symptoms.
In order to determine the effects of repeated administration under fed and fasting conditions on the bioavailability and clinical efficacy of Uniphyl tablets, 22 adult asthmatics took the drug immediately following their evening meal for seven consecutive days and under fasting conditions for an additional seven consecutive days. For each patient, the daily theophylline dose remained constant throughout the study. Peak and trough serum theophylline concentrations (STC), spirometry, asthma symptoms, side effects and use of beta-agonist inhalers were recorded daily at 0730 and 1900 hours. The mean daily theophylline dose was 818.2 +/- 213.0 mg. The mean peak STC when Uniphyl was taken with food was 14.4 +/- 4.5 mg/L and was 13.1 +/- 3.6 mg/L when taken under fasting conditions (P less than .05). The trough STC was 7.4 +/- 2.8 mg/L with food and 6.9 +/- 2.1 mg/L while fasting (NS). There were no significant differences between the two dosing conditions in terms of spirometry, asthma symptom scores, side effects or use of beta-agonist inhalers. There was no significant difference between the patients' morning and evening FEV1 under either dosing condition. Since the differences in STC between fed and fasting conditions were not clinically significant, we conclude that there is no need to restrict patients to a rigid relationship between Uniphyl dosing and meal conditions. On the basis of patient preference and compatibility with a normal lifestyle, we recommend that patients should generally be instructed to take the drug with or shortly following their evening meal.