Theophylline clearance: Effect of marked obesity

Abstract

Total body clearance (ClT) of theophylline [used to treat bronchospastic disease] was examined in 12 markedly obese patients and related to total body weight (TBW) and ideal body weight (IBW). Patients were infused with aminophylline continuously and evaluated at steady state. Total body clearances of theophylline were 29.5 .+-. 7.8 ml/h per kg TBW and 58.8 .+-. 15.9 ml/h per kg IBW. In patients with congestive heart failure (CHF) (no. = 4) theophylline ClT was 19.7 .+-. 1.9 ml/h per kg TBW or 47.7 .+-. 8.3 ml/h per kg IBW while in those with no CHF (no. = 8) clearance was 34.5 .+-. 3.5 ml/h per kg TBW or 64.3 .+-. 16.2 ml/h per kg IBW. Acute renal failure did not appear to alter theophylline ClT in 2 patients (1 with and 1 without CHF). Mean theophylline ClT closely approximated that of a normal population when corrected for IBW, but there was a much stronger correlation between theophylline ClT and weight when corrected for TBW. Maintenance doses of theophylline in markedly obese patients with CHF should be based on a theophylline ClT of 19.7 ml/h per kg TBW and of 34.5 ml/h per kg TBW in those with no CHF.