Asthma, a chronic inflammatory disease of the airways, causes wheezing, shortness of breath, chest tightness, coughing and a narrowing of the airway. Found in plants as well as blood, urine and several organs within the body, xanthines and xanthine derivatives such as theophylline have traditionally been used to treat patients with asthma and chronic obstructive pulmonary disease, or COPD.
Effect
Xanthines are a collection of alkaloids, or naturally occurring chemical compounds. These alkaloids have a pharmacological effect and are used as mild stimulants, anti-inflammatories and as bronchodilators.However, the drug causes a relatively weak bronchodilation, or opening of the airway. However, how xanthines work or the mechanism of action is not completely understood, therefore its use in asthma and COPD has been relegated to a second- and sometimes third-line medication.
Clinical Significance
Methylxanthines such as theophylline have been used to treat asthma since the early 1940s, according to the U.S. National Library of Medicine. However, theophylline and other xanthine derivatives can be very toxic, requiring frequent blood tests to determine drug levels in the body. According to MedlinePlus, life-threatening levels can cause seizures and cardiac arrhythmia. Lower levels of toxicity can cause GI upset, blood pressure changes and difficulty breathing, to name a few symptoms. There are currently several drugs on the market with fewer side-effects that are substantially more effective in treating the symptoms of asthma.
Use in Asthma
A sustained-release theophylline has been used as an alternative drug for maintenance therapy of mild, persistent asthma. However, low-dose inhaled corticosteroids are preferred over theophylline, simply because the mechanism of action for corticosteroids are clearly understood. According to "Rau's Respiratory Care Pharmacology," many clinicians prefer other drugs over xanthines or theophylline, because even though its mechanism of action is not clearly understood, the toxicity potential is.
Xanthine Agents
According to "Rau's Respiratory Care Pharmacology," xanthine derivatives used as bronchodilators in the treatment of asthma and COPD include theophylline, sold as Theo-Dur, Slo-Phyllin, Theolair and Slo-Bid. Another xanthine derivative is oxtriphylline, sold as Choledyl SA. Aminophylline is sold as Aminophylline, and dyphylline is sold as Dylix and Lufylin. If you see or hear any of these names, you know that the drug is considered a xanthine agent or medication.
References
- "Rau's Respiratory Care Pharmacology"; Douglas S. Gardenhire, EdD, RRT; 2008
- Journal of Allergy and Clinical Immunology: Relationships between Adenosine, Cyclic Nucleotides, and Xanthines in Asthma
- Handbook of Experimental Pharmacology: Methylxanthines in Asthma
- MedlinePlus: Aminophylline Overdose
