Products
Theophylline is commercially available as sustained-release tablets and as an injectable (Unifyl, Aminophylline). It has been approved in many countries since 1954. Euphylline is no longer marketed.
Structure and properties
Theophylline (C7H8N4O2, Mr = 180.2 g/mol) is a white crystalline powder that is sparingly soluble in water. It is a methylxanthine and structurally related to caffeine. It is also present in some drugs as theophylline ethylenediamine, which is readily soluble in water.
Effects
Theophylline (ATC R03DA04) has bronchodilator, anti-inflammatory, diuretic, and vasodilator properties and causes vasodilatation in the airways and blood vessels. Many theophylline effects are due to inhibition of phosphodiesterases (PDE). Theophylline is prescribed cautiously and particularly for symptom control in inadequately treated bronchial asthma. In COPD, it shows good anti-inflammatory effects.
Indication
Reversible bronchial obstruction in bronchial asthma or chronic obstructive pneumopathy (COPD). Parenterally, it is used to treat status asthmaticus.
Dosage
According to the drug label. In various clinical situations (eg, dose titration or change of sustained-release drug), determinations of plasma levels may be useful.
Contraindications
- Hypersensitivity
- Acute myocardial infarction
- Cardiac arrhythmia
For complete precautions, see the drug label.
Interactions
Theophylline is metabolized primarily via CYP1A2, which is why plasma levels can vary widely between individual patients. Numerous drug-drug interactions are possible via CYP1A2. It is important to consider these during treatment because they can lead to dangerous overdose. Full details of drug interactions can be found in the SmPC.
Adverse effects
The most common adverse effects include digestive disturbances such as diarrhea, nausea, and vomiting. They often occur at the beginning of therapy, and can be avoided by slowly increasing the dose. If these side effects occur during long-term therapy, plasma levels may be too high, and a review of concomitant medications, as well as patient factors, is prudent. Other possible side effects include cardiovascular disturbances such as rapid pulse, arrhythmias, low blood pressure, and palpable heartbeats. Central disorders such as headache, dizziness, restlessness, sleep disturbances, and agitation are common. Other side effects are possible. Cases of poisoning are frequently described due to a dosage that may be too high.
Cf.
Roflumilast
