| Formulary Chapter 3: Respiratory system - Full Chapter
Theophylline (Uniphyllin Continus®)
Uniphyllin Continus® Modified release tablets 200mg, 300mg, 400mg
(Note: Slo-Phyllin® Modified release capsules of all strengths have been discontinued by the manufacturer. Further details can be found here.)
(Nuelin SA® Modified release tablets 175mg, 250mg have also been discontinued by the manufacturer.)
Theophylline is seldom used, but may be used for severe asthma and COPD. Initiate therapy on a low dose and increase slowly if there is no therapeutic response.
Theophylline has a narrow margin between therapeutic and toxic dose and must be monitored closely with frequent blood tests. The therapeutic range for theophylline is 10-20mg/litre.
- Initiation of IV therapy: 4-6 hours
- Subsequent levels for IV therapy: every 24 hours
- Initiation of oral therapy: 2-4 days
- Change of IV dose: 12-24 hours later
- Change of oral dose: 2-4 days
- The half-life is increased (giving higher theophylline levels) in heart failure, cirrhosis, and viral infections, in the elderly and by drugs such as cimetidine, ciprofloxacin, erythromycin, fluvoxamine, diltiazem, verapamil and oral contraceptives. The half-life is decreased (giving lower theophylline levels) in smokers, and in chronic alcoholism, and by drugs such as phenytoin, carbamazepine, rifampicin and barbiturates.
- Modified release preparations of theophylline should be prescribed by brand name. Prescribers should not interchange brands of theophylline due to the differences in bioavailability.
- Slo-phyllin® capsules can be opened and the granules sprinkled on soft food prior to administration.
- Vomiting may indicate a toxic dose.