Influence of Gender on Theophylline Dosage Requirements in Children with Chronic Asthma

The total daily dose of theophylline required to achieve a four-hour steady-state serum concentration within the 10–20 μg/ml therapeutic range was examined for 49 age-matched pairs of female and male children, age 5–15 years, with chronic asthma. All patients received the same 100 percent bioavailable slow-release product (Theodur®) at eight-hour intervals for more than 72 hours. Total body clearance of theophylline was estimated from the four-hour measurement which closely approximated the average serum concentration. A clinical pharmacist interviewed all patients or parents before a blood sample was obtained to document compliance and other factors that might alter the interpretation and reliability of the measurement.