Theophylline TDM

Question 1

What type of drug is theophylline & what does it do in asthma?

Answer 1

It is an xanthine derivative which induced bronchodilation in asthma

Question 2

Why is theophylline useful for night-time symptoms?

Answer 2

Because it has a long duration of action

Question 3

What should the therapeutic range of theophylline be?

Answer 3

10-20mg/L

Question 4

What conc. of serum theophylline levels should never be exceeded due to toxicity?

Answer 4

> 20mg/L

Question 5

What should you always monitor for theophylline?

Answer 5

U&E - especially K+
Serum levels
Smoking status
LFTs
Lung function

Question 6

What are the signs of theophylline toxicity?

Answer 6

N+V
Diarrhoea
Palpitations
Nervousness
Agitation
Seizures
Arrhythmia

Question 7

What would you have to do to the theophylline dose if the patient is a smoker, or is a chronic alcoholic?

Answer 7

Smoking/alcoholism are liver enzyme inducers, meaning plasma conc. of theophylline decreases, so a higher theophylline dose would be needed

Question 8

What would you have to do to the theophylline dose if the patient has HF/cirrhosis/elderly/has acute alcohol?

Answer 8

These factors are all enzyme inhibiting, so plasma conc. of theophylline will rise and so a lower theophylline dose would be needed

Question 9

What enzyme inhibiting drugs increase theophylline serum levels?

Answer 9

Acute alcohol
Cimetidine
Ciprofloxacin
Erythromycin
Clarithromycin
Ketoconazole

Question 10

What enzyme inducing drugs decrease theophylline serum levels?

Answer 10

Carbamazepine
Phenytoin
Rifampicin
St Johns Wort
Smoking
Barbituates
Alcoholism