THEOPHYLLINE

Question 1

THEOPHYLLINE INDICATIONS

Answer 1

For Uniphyllin Continus® -

• Chronic asthma
• Reversible airways obstruction,
• Severe acute asthma

SAME BRAND OF THEOPHYLLINE SHOULD BE MAINTAINED

Question 2

Therapeutic drug monitoring

Answer 2

Target plasma-theophylline concentration of 10–20 mg/litre (55–110 micromol/litre) is required for satisfactory bronchodilation, although a lower plasma-theophylline concentration of 5–15 mg/litre may be effective.

Adverse effects can occur within the range 10–20 mg/litre and both the frequency and severity increase at concentrations above 20 mg/litre.

Plasma-theophylline concentration is measured 5 days after starting oral treatment and at least 3 days after any dose adjustment. A blood sample should usually be taken 4–6 hours after an oral dose of a modified-release preparation (sampling times may vary—consult local guidelines).

Question 3

When to measure plasma levels

Answer 3

Plasma-theophylline concentration is measured 5 days after INITIATION

At least 3 days after any dose adjustment

A blood sample should usually be taken 4–6 hours after an oral dose of a modified-release preparation (sampling times may vary—consult local guidelines).

Question 4

Dose adjustments due to interactions for theophylline

Answer 4

Dose adjustment may be necessary if smoking started or stopped during treatment.

Theophylline is metabolised in the liver. The plasma-theophylline concentration is increased in heart failure, hepatic impairment, and in viral infections.

The plasma-theophylline concentration is decreased in smokers, and by alcohol consumption.

Question 5

If a patient wants to reduce or quit smoking?

Answer 5

Dosage of theophylline should be decreased

Question 6

TOXICITY EFFECTS - SICK + FAST

Answer 6

VOMITING

AGITATION

DILATED PUPILS

TACHYCARDIA + ARRHYTHMIAS

HYPERGLYCEAMIA

CONVULSIONS

TREAT TOXICITY WITH ACTIVATED CHARCOAL