Coughing is a normal and reflexive response to irritants in the throat and lungs. It’s a way for the body to keep airways clear, but when cough persists for a long time, it can be both annoying and exhausting.

Chronic cough, which lasts more than eight weeks, is a common problem that affects millions of people. It can be caused by many factors, including allergies, acid reflux, asthma, infections, and chronic obstructive pulmonary disease (COPD).

Many people find relief from cough symptoms through lifestyle changes, such as quitting smoking and avoiding triggers, but when these methods fail, medication may be necessary.

The Need for New Medicines

The treatment of cough has always been challenging for doctors, as there are few effective remedies available. Most drugs used to treat cough are either ineffective or have significant side effects.

The mainstay of cough treatment is cough suppressants, which work by blocking the cough reflex. However, they can cause sedation, respiratory depression, and addiction, especially if used for a long time. On the other hand, expectorants, which are aimed to thin and loosen mucus, have little evidence for their effectiveness.

Recently, a new medicine has been developed that shows promise in the treatment of chronic cough. It uses a novel mechanism to suppress cough reflex, which may avoid the adverse effects seen in traditional cough suppressants.

This article will explore the science behind this new medicine and how it can help people suffering from chronic cough.

Science Behind the New Medicine

The new medicine, called gefapixant (also known as AF-219), is a selective antagonist of the P2X3 receptor. This receptor is found on sensory nerves in the airways and plays a crucial role in the cough reflex.

When irritants, such as inhaled particles or inflammatory substances, activate the P2X3 receptor, it triggers the sensory nerves to send signals to the brain, which then stimulates the cough reflex. By blocking the P2X3 receptor, gefapixant can reduce the sensitivity of the nerves, preventing the cough reflex from being triggered as easily.

The effectiveness of gefapixant has been demonstrated in several clinical trials. In a phase IIb study conducted on 253 patients with unexplained chronic cough, gefapixant significantly reduced cough frequency compared to placebo.

The reduction was dose-dependent, meaning higher doses resulted in greater cough suppression. In addition, the drug was well-tolerated, with no serious adverse effects reported.

Benefits of the New Medicine

The main benefit of the new medicine is its ability to suppress cough without causing sedation or respiratory depression.

Traditional cough suppressants, such as codeine, dextromethorphan, and hydrocodone, all have sedative properties, which can impair the ability to drive, operate machinery, or perform other tasks that require alertness. They can also cause respiratory depression, especially in people with underlying respiratory diseases, such as asthma or COPD.

In contrast, gefapixant acts specifically on the P2X3 receptor, which is only present in sensory nerves in the airways, and has no effect on other receptors in the brain or spinal cord that are responsible for sedation or respiratory control.

Another benefit of the new medicine is its targeted mechanism of action.

Unlike general cough suppressants, which work by suppressing all cough reflexes, including those that are necessary for clearing secretions and protecting the airways, gefapixant targets only the hyperactive reflex that causes chronic cough. This means that the drug can reduce cough frequency and severity without compromising the overall respiratory function.

Who Can Benefit from the New Medicine

The new medicine is intended for patients with chronic cough that is not due to an underlying respiratory condition, such as asthma or COPD.

These patients often have a persistent and disabling cough that affects their quality of life and interferes with daily activities, but current treatments are often ineffective. If lifestyle modifications, such as avoiding irritants and humidifying the air, don’t provide relief, the new medicine may be an option.

However, before starting any new medication, patients should consult with their doctor to determine the underlying cause of cough and rule out any serious health problems.

Conclusion

Chronic cough is a common problem that can be difficult to treat. However, the development of a new medicine that targets the underlying mechanism of cough is a promising development.

By selectively blocking the P2X3 receptor, gefapixant can reduce cough frequency and severity without causing sedation or respiratory depression. For people with chronic cough that is not due to an underlying respiratory condition, the new medicine may provide relief and improve their quality of life.