Theophylline, Serum


Theophylline is used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). As a bronchodilator, theophylline directly relaxes human airways smooth muscle and, like β-agonists, acts as a functional antagonist, preventing and reversing the effects of all bronchoconstrictor agonists. Theophylline may also have an additional effect on mucociliary clearance through a stimulatory effect on ciliary beat frequency and water transport across the airway epithelium. There is increasing evidence that theophylline has anti-inflammatory effects in asthma and COPD. Several drugs including macrolide and quinolone antibiotics, cimetidine and fluvoxamine may increase plasma theophylline concentrations to levels that produce side effects (headache, nausea and vomiting, abdominal discomfort, and restlessness, increased acid secretion, gastroesophageal reflux, and diuresis). At high theophylline concentrations, convulsions, cardiac arrhythmias and death may occur.


Measurement of theophylline level is used in the management of patients with Asthma and COPD. Desired therapeutic effects are achieved at concentrations between 10 - 20 μg/mL. Toxic effects are reported at concentrations higher than 20 μg/mL.

Sample Type, Quantity & Conditions

1 ml Serum 1 ml Li-Heparin or K2, K3-EDTA Plasma Stability: 1 Week at 2-8 °C 6 Months at -20 °C

Special Precautions

Sampling time: 4 Hrs after oral solid dose or 1 Hr after I.V. or oral liquid dose. Avoid lipemic and haemolysed samples.

Normal Range

Referance range: 10.00-20.00 μg/mL Panic: > 20 μg/mL Neonates: > 10 μg/mL

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