Common Cough Medicine Might Help Treat Lung Scarring Disorders

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- Updated by Jody Mullis
Medically reviewed by Dr. Sidra Samad

  • Pulmonary fibrosis (PF) is a severe lung condition that causes scarring and breathing difficulties.
  • Over 250,000 Americans are affected by PF, which has no cure.
  • A common cough suppressant, dextromethorphan (DXM), has shown potential as a treatment for PF.
  • The study revealed that DXM reduces lung scarring in mouse models.
  • DXM works by lowering collagen buildup, which is responsible for fibrosis progression.
  • DXM’s established safety profile makes it an accessible option for further clinical development.

Why This Matters to Us

As longevity enthusiasts, we are always interested in treatments that can alleviate chronic illnesses and improve quality of life, particularly for age-related conditions. Pulmonary fibrosis not only reduces lifespan but also severely impacts day-to-day wellbeing. This study on dextromethorphan (DXM) is particularly exciting because it could open doors to an affordable and widely available therapy for a devastating disease that currently has no cure. If DXM proves effective in humans, it could lead to meaningful advances in fighting diseases associated with ageing, which is a significant focus in our quest for longevity.

The Detail

Pulmonary fibrosis (PF) is a progressive and often deadly disease that causes scarring (fibrosis) in the lungs. Over time, this scarring stiffens the lungs, reducing their capacity to transfer oxygen into the blood. As the condition worsens, patients experience increased shortness of breath, coughing, fatigue, and potentially life-threatening complications like respiratory failure. In the US alone, more than 250,000 people live with PF, and up to 50,000 new cases are diagnosed every year. Currently, there are no cures, and the few existing treatments, such as pirfenidone and nintedanib, focus only on slowing down the disease's progression. Therefore, researchers are continuously searching for alternative therapies.

A recent study published in Science Translational Medicine investigated the effects of dextromethorphan (DXM), a widely used cough suppressant sold in many over-the-counter remedies. The researchers found that DXM significantly reduced signs of fibrosis in various experimental settings. These included lab studies with human cells, tissue-based systems, and animal models of pulmonary fibrosis.

The key to this discovery lies in collagen, a major structural protein in connective tissues. While collagen is essential in healthy amounts, an excessive buildup in the lungs leads to scarring, stiffness, and loss of function. The researchers determined that DXM reduces collagen production, thereby limiting the progression of fibrosis.

In lab tests, researchers cultured human lung cells under conditions designed to mimic fibrotic tissues. When DXM was added to this environment, the production of collagen type I—the key culprit behind fibrosis—was significantly reduced. Collagen accumulation also decreased in studies involving lung, skin, and kidney tissues. Importantly, these findings were not limited to cell-based experiments. The researchers conducted further tests on mice to understand how DXM could work in a living organism with lung fibrosis.

Mice were treated with DXM at different times and doses, simulating both preventative and therapeutic approaches. In the preventative case, the medicine was administered right from the onset of fibrosis-inducing damage. For the therapeutic case, DXM treatment started after the disease symptoms had already developed. In both scenarios, DXM reduced fibrosis markers in the lung tissue of the mice. These reductions were associated with better lung structure and less scarring.

This antifibrotic effect is closely related to DXM’s ability to block the transformation of fibroblasts into myofibroblasts. Myofibroblasts are specialised cells that produce large quantities of collagen, leading to scarring. By inhibiting this transformation, DXM helps prevent the key processes driving lung fibrosis. The researchers concluded that DXM acts on multiple levels to reduce collagen buildup and stabilise tissue function.

Why DXM Is Promising

One of the most exciting aspects of this study is that DXM has already been widely used for decades as a cough suppressant, meaning its safety profile is well-documented. In addition, it is available over the counter, making it far more accessible than many experimental drugs. The study’s findings suggest that DXM could one day be repurposed as an antifibrotic treatment not just for pulmonary fibrosis, but potentially for other age-related fibrotic diseases as well, such as liver or kidney fibrosis.

While these findings are promising, it is important to note that this study primarily involved cell cultures and animal models. To confirm DXM’s potential, researchers will need to conduct clinical trials in humans. Factors such as optimal dosing, long-term effects, and its efficacy among patients with advanced fibrosis are areas that need further exploration.

Looking Ahead

As we continue our pursuit of healthy ageing, DXM’s potential as a treatment for pulmonary fibrosis represents exciting progress in the field of longevity medicine. By targeting collagen buildup, which is a hallmark of fibrotic diseases, DXM may offer a way to slow down or even halt the progression of conditions that severely impact longevity and quality of life. While further research is required to transition these findings into real-world therapies, the accessibility and established safety record of DXM make it a strong contender in the fight against PF and related diseases.

For more information about pulmonary fibrosis, visit the Pulmonary Fibrosis Foundation’s website.