THEOPHYLLINE

Question 1

Therapeutic range of theophylline

Answer 1

10-20mg/l

Question 2

how often does drug plasma levels need to be checked in theophylline

Answer 2

• 4-6HR after each dose
• 5DY after tx
• at least 3DY after dose change

Question 3

why should same brands be prescribed and dispensed

Answer 3

brands don’t have same bioavailability

Question 4

s/e of theophylline

Answer 4

• vomiting
• palpitations
• arrythmias

Question 5

theophylline interactions

Answer 5

• smoking -increases theophylline clearance (if pt stops smoking dose changes needed)
• fever = reduces clearance
• CYP enzyme inducers decrease conc
• CYP inhibitors inc conc
• drugs that cause hypokalaemia corticosteroids, SABA/LAMA, diuretics