Intravenous theophylline therapy: nomogram guidelines

Area of Science:

• Pharmacology
• Clinical Therapeutics
• Medical Nomograms

Background:

• Intravenous theophylline is crucial for managing respiratory conditions.
• Standardizing theophylline dosing is challenging due to variable patient metabolism.
• Accurate dosing is essential to maintain therapeutic serum concentrations and minimize toxicity.

Purpose of the Study:

• To develop and validate a nomogram for guiding intravenous theophylline therapy.
• To standardize the calculation of loading doses and maintenance infusion rates.
• To improve the management of theophylline therapy in hospitalized patients.

Main Methods:

• Evolved a nomogram for calculating theophylline loading dose (based on body weight and prior therapy) and maintenance infusion rate (based on metabolic activity categories).
• Prospectively applied the nomogram in the treatment of 72 hospitalized patients, primarily in a respiratory care unit.
• Monitored serum theophylline concentrations to assess nomogram efficacy.

Main Results:

• The nomogram successfully achieved near-steady-state serum theophylline concentrations within the therapeutic range (8–20 mg/litre) in 72% of patients.
• Only two patients had concentrations outside the broader range of 5–25 mg/litre.
• The nomogram facilitated initial dosing and provided a basis for interpreting and adjusting therapy.

Conclusions:

• The developed nomogram effectively guides and standardizes intravenous theophylline therapy.
• This tool aids in achieving therapeutic serum concentrations, particularly in older patients or those with comorbidities like liver and cardiac disease.
• The nomogram offers a rational approach to theophylline dosage adjustment and interpretation of serum levels.