Pharmacokinetics of an ultralong sustained‐release theophylline formulation when given twice daily in elderly patients with chronic obstructive pulmonary disease: Monitoring implications

Abstract

The steady-state pharmacokinetics of an ultralong sustained release formulation of theophylline (Unilong) twice daily (bid) in elderly hospitalized patients suffering from chronic obstructive pulmonary disease (COPD) have been studied in order to establish guidelines for monitoring. The study was carried out in 37 patients (33 men), aged 60-87 years. Samples were collected from 0 to 12 h after the morning dose on day 9 of treatment with 250 mg bid (n=25) or 375 mg bid (n=12). Considerable variability in apparent clearance (range 0.33-1.49 ml/min per kg of ideal body weight), Css(min)/D (range 0.28-1.86), Css(max)/D (range 0.65-2.33) and (Css(max)-Css(min))/Css(avg) (range 0.18-0.80) was observed. There was no significant correlation between the patient's age and apparent clearance within this elderly population. The concentration-to-dose ratio and the relationship between the steady-state plasma concentration at different times during the dosage interval and Css(avg) are described. It is concluded that the interpatient variability in peak-trough fluctuation of this formulation was higher than that described in healthy volunteers by other investigators, and that the apparent clearance did not decrease with age within this elderly population with COPD. The importance of theophylline monitoring is emphasized and rules to estimate Css(avg) and Css(5h) from Css(0h) when only a single sample obtained before the morning dose is available are given.

Do We Need Different Treatments for Very Elderly COPD Patients?

“…Toxicity is dose-related and problems include: arrhythmias, convulsions, hypokalemia, hyperglycemia, hypercalcemia, hypophosphatemia, acidosis, nausea, vomiting, headache, insomnia, and nausea. One study showed reduced clearance and an increased half-life of theophylline with advancing age [103], in contrast with other studies [104,105] which found no significant correlation between patient age and theophylline clearance. Older adults have a higher risk of toxicity when taking theophylline because of concomitant diseases, especially cardiovascular disease, reduced drug clearance, and polypharmacy, with consequent potential drug-drug interactions.…”