Theophylline - serum
Last updated: Tuesday, 30, March, 2004
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5 mL blood in plain tube.
Preferably collected pre-dose; timing of post-dose peak varies with formulation.
| Therapeutic Interval|
Neonate: 33-66 µmol/L (6-12 mg/L)
Child, adult: 55-110 µmol/L (10-20 mg/L)
Monitoring theophylline therapy.
During acute illness, the half-life may be prolonged beyond the usual range of 3-9 hours.
Toxicity may develop if the dosage is not reduced. Toxicity may occur within the therapeutic interval in some patients.
Cigarette smoking reduces the half-life and therefore decreases levels significantly.
Glynn-Barnhart A et al. Drugs 1988; 35: 711-726.