Intravenous theophylline therapy: nomogram guidelines.

We evolved a nomogram for guiding and standardizing intravenous theophylline therapy in hospitalized patients. It provides rapid calculation of a loading dose based on body weight and previous therapy and a maintenance infusion rate related to three categories of expected metabolic activity. The guidelines were prospectively used in the treatment of 72 patients, mainly in a respiratory care unit. The nomogram was successfully used to attain near-steady-state serum concentrations in the therapeutic range of 8 to 20 mg/litre in 72% of patients, with only two patients outside of the range of 5 to 25 mg/litre. These guidelines facilitate initial theophylline dosage in older patients with liver and cardiac disease and provide a rational basis for interpreting serum concentration measurements and adjustment of drug therapy.