Theophylline
Also known as: Aminophylline, Blood, Elixophyllin® Elixir, Theo-24®, Theo-Dur®, Theochron™
Use
Theophylline is prescribed for bronchial asthma, chronic obstructive pulmonary disease, and newborn apnea. It's important for monitoring serum levels due to its extensive metabolism and the influence of various factors like drug interactions, heart failure, liver disease, infections, and smoking on its clearance and half-life. Optimal resampling time after dosage changes is critical to avoid toxicity, which can occur over a wide range of theophylline levels, unrelated to serum concentrations.
Special Instructions
Blood levels should be interpreted in the context of the patient's clinical status and concurrent medication usage. Monitoring is crucial as toxic effects can include nausea, vomiting, arrhythmias, and convulsions. Avoid using gel-barrier tubes as they may absorb the drug, affecting accuracy of results.
Limitations
The association between severity of toxic effects and serum concentrations is not definite, as shown by studies. Trough levels should be carefully timed. Gel-barrier tubes are known to absorb theophylline, potentially leading to significant decreases in measured drug levels. Half-life and required drug dose can vary greatly among different patient conditions and smoking status.
Methodology
Immunoassay
Biomarkers
LOINC Codes
- 4049-3
- 4049-3
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube or green-top (heparin) tube. Do not use a gel-barrier tube.
Collection Instructions
Transfer separated serum or plasma to a plastic transport tube. Trough: immediately prior to next dose; after change in dose: children: two days, adults: one to two days.
Storage Instructions
Room temperature
Causes for Rejection
Gel-barrier tube; hemolysis; gross lipemia; icteric specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |