The pharmacokinetics of uniphyllin in nocturnal asthma.

Three consecutive doses of approximately 10 mg/kg of a once daily slow-release theophylline preparation (Uniphyllin) were given at 22.00 hours to 15 patients with nocturnal asthma who were recovering from an acute exacerbation of their asthma. Twenty-four hour plasma theophylline profiles were obtained after the first and third doses. Following the first dose, the mean peak level was 12.5 mg/litre, mean time to peak was 8.1 hours and mean apparent elimination half-life was 6.6 hours. Pharmacokinetic data were similar following the third dose. In nocturnal asthma, Uniphyllin should be given at about 20.00 hours to coincide peak levels with the time of maximum airflow obstruction.