Cimetidine-theophylline interaction: report of four patients.

Four patients who had experienced a cimetidine-theophylline interaction are reported. All patients displayed decreases in theophylline elimination after the introduction of cimetidine. Clearances approached baseline values when cimetidine was discontinued. Patients on this drug combination should be monitored closely for signs of theophylline toxicity. When indicated, a beta agonist may be a better choice of a bronchodilator for peptic ulcer patients.