Pharmacokinetics of Theophylline in Ten Elderly Patients

Abstract

The 2-compartment pharmacokinetics of theophylline in 10 hospitalized elderly patients with apparently normal renal, hepatic and cardiopulmonary functions was investigated after i.v. administration of the drug. Nine patients suffered from slight hemiparesis and 1 from Parkinson''s disease. Biological theophylline half-lives of 5.4-9.0 h and plasma clearance values of 28-42 ml kg-1h-1 were found. The apparent volumes of distribution during the .beta.-phase, Vd.beta., were 0.33-0.43 1 kg-1. A therapeutic concentration of about 10 .mu.g theophylline/ml serum could be established in the investigated group of elderly patients following an i.v. initial loading dose of 3.7 theophylline/kg followed by a continuous infusion of 0.35 mg/kg body wt per h. In the therapeutic use of theophylline, monitoring of the serum theophylline concentration is generally advised because of reported variability in the biological half-life of the compound.