Theophylline prescribing, serum concentrations, and toxicity.

The use of theophylline in clinical practice has raised concerns about variability in serum concentrations and potential toxicity. Prior research has shown that theophylline metabolism can be affected by factors such as liver function and medication interactions. However, the extent to which serum monitoring influences clinical decisions remains unclear. This gap motivated a retrospective analysis of theophylline prescriptions and serum levels at a single hospital. The study aimed to evaluate the relationship between prescribed doses and measured concentrations. It also sought to determine how often high levels were linked to adverse outcomes. The researchers focused on two distinct patient groups to compare outcomes. This approach allowed them to assess the impact of serum monitoring on treatment adjustments. The findings may help clarify the role of serum theophylline testing in clinical decision-making.

The study aimed to evaluate how serum theophylline monitoring affects prescribing practices and patient outcomes. It focused on patients receiving slow-release theophylline at a single hospital. The researchers wanted to understand the relationship between prescribed doses and actual serum levels. They also sought to identify factors associated with high theophylline concentrations. The study compared two groups: outpatients on stable treatment and those with elevated levels. This comparison allowed the researchers to assess the impact of serum monitoring on management decisions. The goal was to determine how often high levels led to dosage changes. The findings could inform guidelines on the use of serum theophylline testing in clinical practice.

The researchers conducted a retrospective analysis of 1913 serum theophylline assays over 18 months. They divided patients into two groups: 113 outpatients on stable treatment and 28 with concentrations over 25 mg/l. They reviewed medical records to assess the influence of serum levels on management decisions. The study examined the relationship between prescribed doses and measured concentrations. They also looked at factors like liver function and diuretic use. The researchers recorded how often high levels led to dosage reductions. They compared outcomes between patients receiving oral theophylline and those on infusion. This approach allowed them to identify patterns in prescribing and toxicity risks.

In the stable outpatient group, there was a weak correlation between prescribed dose and serum theophylline levels. High concentrations were linked to abnormal liver function, diuretic use, and duplicate prescriptions. When high levels were reported, dosage was always reduced. However, only one-third of patients with low levels had their doses increased. Of the 28 patients with concentrations over 25 mg/l, 18 were on oral theophylline and 10 on infusion. Three patients experienced seizures, two of whom died. One patient required resuscitation after cardiac arrest. These findings suggest that high theophylline levels may contribute to hidden morbidity.

The study found that serum theophylline levels did not consistently reflect prescribed doses. High concentrations were often associated with factors like liver dysfunction and diuretic use. Dosage adjustments were more common after high levels than after low ones. The researchers observed severe outcomes in patients with very high concentrations. These findings suggest that theophylline toxicity may be under-recognized. The study highlights the importance of serum monitoring in identifying at-risk patients. It also raises questions about the reliability of dose-based prescribing. The authors propose that serum testing should be used more routinely in clinical practice.