How theophylline works
Theophylline has a bronchodilator effect and inhibits the release of messenger substances that are necessary for an inflammatory response. The active ingredient can therefore be used – in addition to inhaled therapy – to prevent and treat shortness of breath (as in bronchial asthma and COPD).
In most cases, the attack is triggered by an allergic reaction (allergic asthma). Due to a genetic predisposition, patients are particularly sensitive to certain triggers (allergens). On contact, the body’s defense system (immune system) overreacts and the lungs “spasm”.
Chronic obstructive pulmonary disease (COPD) may or may not be associated with an inflammatory response. The difference to asthma, simply put, is that the constricted bronchi in COPD do not return to their original state despite optimal therapy. This is therefore referred to as “non-reversible airway obstruction”.
Absorption, degradation and excretion
After absorption by mouth (orally), the active substance is practically completely absorbed from the intestine into the blood. Degradation takes place in the liver, after which the degradation products are excreted mainly by the kidneys.
When is theophylline used?
The indications for use (indications) of oral theophylline include:
- Treatment and prevention of persistent bronchial asthma.
- @ Treatment and prevention of moderate to severe obstructive airway disease (such as COPD, emphysema)
Indications for intravenous theophylline include:
How theophylline is used
Theophylline has a very narrow “therapeutic range”. This means that in terms of dosage, there is only a very fine line between ineffectiveness and overdose, in which the correct dosage for optimal effect is found.
The active ingredient can also be used for acute respiratory distress. In this case, solutions are available that are injected intravenously and can thus develop their effect immediately.
The dosage is determined individually for each person. Optimal blood levels are between 5 and 15 micrograms per milliliter.
Optimally, theophylline is combined with other drugs for respiratory disorders such as glucocorticoids or β2-sympathomimetics such as salbutamol, salmeterol, or fenoterol.
Because of its narrow therapeutic range and weaker effect compared with inhaled drugs, theophylline is not a first-line agent for the treatment of respiratory disease.
What are the side effects of theophylline?
Due to its narrow therapeutic range, theophylline can be easily overdosed: Symptoms then occur at blood levels as low as 20 micrograms per milliliter, and become more frequent and severe the more severe the overdose.
Acute symptoms include nausea, vomiting, diarrhea, restlessness, tremors, increase or decrease in blood pressure, increase in respiratory rate, cardiac arrhythmias, convulsions, and in severe cases coma.
If you notice any signs of overdose, contact a doctor as soon as possible!
What should be considered when taking theophylline?
Contraindications
Medicines containing theophylline must not be used in:
- known hypersensitivity to theophylline or any of the other ingredients of the medication
- acute myocardial infarction
- @ certain forms of cardiac arrhythmia
Drug interactions
Theophylline may interact with some other medications. For example, when administered at the same time, it enhances the effects of the following substances:
- Caffeine
- Betasympathomimetics (bronchodilators)
- diuretics (diuretic agents)
Conversely, theophylline may weaken the effects of the following agents:
- Benzodiazepines (tranquilizers)
- Lithium (e.g., for bipolar disorder)
- Beta-blockers (heart medication)
The following drugs potentiate the effects and side effects of theophylline:
- some antibiotics (such as erythromycin, clarithromycin, and many fluoroquinolones)
- propranolol (beta blockers)
- cimetidine and ranitidine (medicines for stomach problems)
- Aciclovir (remedy for herpes)
Taking the following medications will weaken the effectiveness of theophylline:
- rifampicin (antibiotic against tuberculosis)
- St. John’s wort (against depressive moods)
Smokers generally have twice the rate of theophylline breakdown as nonsmokers. This usually necessitates a dose adjustment.
Because of the multiple possibilities for interaction, plasma levels of theophylline should always be monitored when there is a change in medication – i.e., the patient is given another drug or discontinues a previously used one.
Trafficability and operation of machines
Age restrictions
Infants under six months of age should receive medications containing theophylline only after a strict risk-benefit evaluation by the treating physician.
Pregnancy and lactation
Medicines containing theophylline may also be taken during breastfeeding. However, the active substance passes into breast milk. Depending on the maternal plasma level, this can lead to an accumulation of the active substance in the infant, so that the infant should be carefully monitored for side effects.
It is advisable to select the lowest possible theophylline dosage and to avoid caffeinated beverages during both pregnancy and breastfeeding.
Medicines containing theophylline are subject to prescription in Germany, Austria and Switzerland. You can therefore only obtain them from a pharmacy with a prescription from your doctor.
How long has theophylline been known?
Theophylline has been known for a relatively long time. The substance was first isolated from tea leaves as early as 1888. However, its chemical structure was not fully elucidated until 1895.
Representatives of xanthines (theophylline, theobromine, caffeine) are found in coffee beans, black and green tea, kola nuts and guarana.