Theophylline is one of the most important active substances for the treatment of respiratory diseases. It is used especially in the treatment of bronchial asthma.
What is theophylline?
Theophylline is one of the most important agents used in the treatment of respiratory diseases. It is particularly used in the treatment of bronchial asthma. Theophylline, a drug, comes from the purinal alkaloid group and is derived from xanthine. The name theophylline can be traced back to tea leaves. In 1888, the German physician Albrecht Kossel (1853-1927) succeeded in isolating small amounts of the substance from tea leaves. In addition, theophylline is found in coffee beans, guarana and kola nuts, albeit in small amounts. In human metabolism, theophylline functions as a breakdown product of caffeine. Around 1895, the German chemist Emil Fischer (1852-1919) managed to produce theophylline synthetically, starting from 1,3-dimethylureic acid. The Traube synthesis described by the chemist Wilhelm Traube (1866-1942) in 1900 represents a chemical synthesis process that is still used today. Theophylline was initially used therapeutically as a diuretic. From 1921, the active ingredient was also introduced in the treatment of angina pectoris. Since 1922, theophylline has been an integral part of the treatment of bronchial asthma. From the 1970s onward, theophylline preparations that release the active ingredient with a delay also entered the market, making it possible to provide long-term therapy for asthma patients. However, theophylline later lost importance due to the introduction of beta-sympathomimetics and glucocorticoids. In nature, theophylline always occurs together with other purine alkaloids. These include primarily caffeine as well as theobromine. Theophylline content is highest in guarana, at 0.25 percent.
Pharmacological effects
Theophylline belongs to the xanthine derivatives and has different effects. For example, the drug inhibits the breakdown of the neurotransmitter CAMP. This, in turn, results in the relaxation of bronchial smooth muscle and provides easier breathing. At the same time, the activity of the cilia increases, leading to increased mucus clearance. Also of importance is the inhibition of the messenger substance adenosine within the bronchial muscles. In this way, the bronchial tubes can dilate and become slack. Another effect is the blocking of adenosine in the brain. Because adenosine is also responsible for regulating sleep, the use of theophylline carries the risk of being weighed down by sleep problems. Furthermore, theophylline brakes the release of histamine. The neurotransmitter histamine is increasingly released in the human body in the context of allergies and infections. Histamine mediates inflammatory reactions and causes the bronchial muscles to constrict. By blocking this messenger substance, the inflammatory symptoms of chronic bronchitis or bronchial asthma are weakened. However, the anti-inflammatory properties of theophylline are weaker than those of glucocorticoids. After oral administration of theophylline, absorption of the drug occurs via the blood into the intestine. Degradation of the drug occurs in the liver, while the breakdown products exit the body via the kidneys.
Medical application and use
For use, theophylline is mainly used to treat moderate and severe asthma. In this context, the drug is often combined with glucocorticoids as well as beta-2-adrenoceptor agonists. Theophylline is suitable for both the prevention and treatment of asthma attacks. Other indications include chronic bronchitis and chronic obstructive pulmonary disease (COPD). In addition, the drug can be used for emphysema (overinflation of the lungs) and chronic pneumonia. An important role in the use of theophylline is the correct dosage of the drug. The optimal effect of the drug depends on this. For this reason, the drug is usually taken in the form of capsules or sustained-release tablets, which ensure a continuous release of the active substance. In this way, there are always constant amounts of theophylline in the patient’s blood. The daily dose varies from patient to patient.Since theophylline is subject to prescription, it can only be obtained from pharmacies upon presentation of a doctor’s prescription.
Risks and side effects
Undesirable side effects are also possible as a result of taking theophylline. In most cases, there is an accelerated heartbeat, palpitations, sleep problems, inner restlessness, trembling of the limbs, headache and low blood pressure. Sometimes cramped bronchial tubes, fever, hives, skin reactions or the reduction of blood platelets are also in the range of possibility. In addition, too high a dosage of theophylline can cause health problems. This becomes noticeable through an abrupt drop in blood pressure, seizures such as epilepsy, severe gastrointestinal complaints accompanied by bleeding, cardiac arrhythmias and damage to the muscles. Since theophylline has a negative effect on the ability to react, participation in road traffic should be avoided. Theophylline should not be administered at all if the patient is hypersensitive to the drug or has acute cardiac arrhythmia. The same applies to a recent heart attack. If the patient suffers from unstable angina, severe hypertension, diseases of the heart muscle, hyperthyroidism, porphyria, gastric or intestinal ulcers, epilepsy, renal or hepatic dysfunction, the treating physician must carefully weigh the risks against the benefits. Interactions may occur due to theophylline being used together with other medications. This applies in particular to the contraceptive pill, beta-2-sympathomimetics, the H2-receptor blockers ranitidine and cimetidine, the vermifuge tiabendazole, calcium channel blockers such as diltiazem and verapamil, macrolide antibiotics such as erythromycin, the gout medicine allopurinol, and the beta-blockers propranolol and interferon, since these have a reinforcing effect on theophylline. In contrast, attenuating effects occur with the use of barbiturates, antiepileptic drugs, the gout medicine sulfinpyrazone, the antibiotic rifampicin, and St. John’s wort.
