Plasma theophylline level and effect on lung function after oral and rectal administration of aminophylline.

Twelve patients with partly reversible, chronic airway obstruction, according to a double blind randomized cross-over design, received on three consecutive days oral aminophylline 500 mg, a 500 mg aminophylline suppository and a placebo. The effects on ventilatory function were studied and the plasma concentration of theophylline was measured. After rectal administration, the plasma concentration of theophylline rose to 5 to 10 microgram/ml, and after oral ingestion the plasma level in most patients exceeded 10 microgram/ml. Administration of the aminophylline suppository resulted in moderate improvement in ventilatory function, and although the improvement was less pronounced than after oral administration, the use of a suppository in the treatment of patients with chronic obstructive lung disease should not be rejected.