 |
Therapuetic Drug Monitoring Information
Please note oral theophylline/aminophylline must be specified by brand
Different brands are not interchangeable
Check interactions with theophyline before prescribing new drugs as further monitoring may be required
| Factors to consider in TDM |
Information |
Further details |
| When level should be done (after initiation) |
5 days |
|
| When bloods should be taken |
4-6hrs post dose |
|
| Optimal drug levels |
10–20 mg/litre
(55–110 micromol/litre) |
Lower drug levels may still provide therapuetic benefit |
| When levels should be taken again following dose alteration |
3 days |
|
| Non-drugs factors which can affect levels |
Increased in:
- Heart failure
- Hepatic impairment
- Viral infections
- Elderly patients
Decreased in:
- Smokers
- Alcohol consumption
|
Consider levels if there are changes in the non-drug factors listed |
| Signs of toxicity |
- Nausea
- Vomiting - Severe and protracted
- Abdominal pain
- Mild metabolic acidosis
- Hypokalemia
- Tachycardia
- Hypophosphatemia
- Hypomagnesemia
- Hypocalcemia/hypercalcemia
- Hyperglycemia
|
Seek advice if suspected |
|
