Theophylline has been used to treat asthma and COPD for more than 80 years. Because it has been around forever, it is sometimes regarded as outdated or “old-school.” And yet much current research indicates that it has a lot to add to the current popular therapies of inhaled steroids, and inhaled short-and long-acting bronchodilators.
Theophylline has been known to have three generalized mechanisms of action: bronchodilation, anti-inflammatory effect and improvement of diaphragm muscle strength.
Now a fourth mechanism is being researched at Lon- don’s National Heart and Lung Institute. Scientists there have found that the drug inhibits the cough reflex through a novel process. They used human and guinea pig research to demonstrate that theophylline decreases excitability of sensory nerves found in the lungs and bronchial tubes that lead to the cough reflex by opening calcium-activated potassium channels.
Almost everyone with asthma and COPD coughs. Coughing can be more troublesome than wheezing in these diseases, as it puts a strain on the body in many ways. Cough can affect urinary continence, lead to hernias and worsen acid reflux issues – which itself often worsens asthma and COPD.
The London scientists are using the theophylline research as a springboard to study new drugs that also may work on the sensory fibers that cause cough.