Theophylline Flashcards
1
Q
What is theophylline used for
A
An antimuscarinic drug used as a bronchodilator in asthma and to stabilise COPD
2
Q
What is theophylline’s therapeutic range
A
10 to 20mg/L
May need loading doses
3
Q
What are the warning signs to report to the GP for theophylline
A
- Toxicity- agitation, vomiting, restlessness, dilated pupils, sinus tachycardia, hyperglycaemia, severe hypokalaemia may develop rapidly convulsions, cardiac arrhythmias
- Symptoms of uncontrolled asthma (cough, wheeze, tight chest)
- Frequent courses of antibiotics and/or oral corticosteroids (poor asthma control)
4
Q
What should you monitor for in theophylline
A
Serum potassium (can cause hypokalaemia)
Plasma theophylline concentration
5
Q
What are the key interactions in theophylline
A
- Potentially serious hypokalaemia form beta agonist therapy (caution in asthmatics as it may be potentiated from corticosteroids, diuretics)- monitor plasma potassium
- Increased plasma concentration with diltiazem, verapamil, erythomycin,
- Increased plasma concentrations of theophylline in elderly patients, heart failure, hepatic impairment, viral infections
- Quionlines + theophylline = convulsions
- Reduced plasma concentration with alcohol, carbmazepine, phenytoin, phenobarbital
- CONCENTRATION IS DECREASED IN SMOKERS (enzyme inhibitor)
6
Q
Why is it important to maintain the same brand of theophylline
A
The rate of absorption can vary between different brands
