The Leeds Teaching Hospitals NHS Trust

Theophylline

Theophylline

Theophylline relaxes bronchial smooth muscles and is used to prevent or treat asthma. It is rapidly cleared from the circulation (The half-life of theophylline in smokers averaged 4.3 (SD = 1.4) hr, significantly shorter than the mean value in nonsmokers (7.0, SD =1.7 hr), (reference Clin Pharmacol Ther. 1976 May; 19 (5 Pt1): 546-51). In neonates the half life is prolonged (20-30 hr) due to immaturity of the liver. Patients with chronic heart failure also tend to have increased half lives. Clearance is a function of a metabolic process that is dose dependent, hence a small dose increase can cause a disproportionately large increase in serum concentration and intoxication. Side effects include sweating, tremor, vomiting, pupil dilation and hyperventilation

Tube 01 (SE) - Serum Gel
ID Tests&Tubes0114
Additional Information For monitoring purposes, blood should not be drawn until a steady state has been attained. This will not be achieved until 24-48 hours after starting therapy or changing dose. In neonates the period may be as long as 5-6 days. Blood should be taken for trough values before a dose. During infusions, blood should be taken after stopping the infusion for 15 min. There is a circadian rhythm of theophylline metabolism, resulting in higher morning trough levels than later in the day. Repeat blood sampling must be done at the same time each day. Theophylline metabolism is associated with large intraindividual variations and levels should be closely monitored.
Turn Around A&E: 1 hour
Day Case: 6 Hours
In-Patient: 6 Hours
Out-Patient: N/A
GP: N/A
Send to Blood Sciences Cross Site
Contact For further details please contact Leeds Pathology customer services: leedsth-tr.pathologycustomerservice@nhs.net.
Collection Con Intensive care units, renal unit, transplant unit, patients on IV heparin use lithium-heparin (Green with Yellow ring) tube. Minimum volume: 500µl serum / plasma
Instructions for Lab Staff: Standard lab processing - No special requirements.
Sample REQ Blood
Ref. Range Notes Blood Sciences reference ranges are available through the useful information and links page:
https://www.leedsth.nhs.uk/a-z-of-services/pathology/blood-sciences/useful-information-and-links/
Units mg/L
Telepath THEO2L
ICE Codes LTHEO