Ingredient In Over-the-Counter Cough Medicine May Be More Than A Placebo

My wife has repeatedly told me that cough medicines don’t work. My doctor has said the same. My retired doctor brother who is more old school, when he spoke to me on the phone during the height of my recent respiratory infection, advised me to get cough medicine containing Dextromethorphan (DXM).

Here’s the thing! I had already bought a bottle of cough syrup containing DXM Bromide and had started taking doses of it with surprisingly effective results. My cough would vanish for hours.

So why the bad rap? DXM has been described by many as no better than a placebo for treating respiratory infections. One of the reasons for skepticism is the dosage requirement to make DXM effective can have adverse side effects and even cause intoxication if overused. And if used to try and treat a serious condition like whooping cough or pneumonia, could cause patients to delay seeking treatment making them worse.

In my personal experience, DXM-containing medicines have always worked to calm my coughing. With my recent pneumonia bout when the DXM stopped helping me, I went to my doctor who put me on a bevy of medications to get me back to good health.

Why have I chosen to write about the much-maligned DXM? Researchers at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, recently described DXM as an effective treatment for lung fibrosis. They have written a research article that appeared in the December 18, 2024 issue of the journal Science Translational Medicine, which describes DXM as a potential therapy for “ending lung failure from the tissues becoming filled with fibrillar collagen.”

DXM was patented in 1949 and approved for medical purposes in 1953. When ingested it acts on the areas of the brain that control the respiratory tract and coughing. An average cough-suppressing dose is one to two teaspoons or 10 to 45 milligrams. In cough syrup, it begins to work within 30 minutes to an hour.

As for DXM use in treating lung fibrosis, the research from EMBL notes it reduces fibrosis by interacting with proteins and peptides that are secreted when the condition is present.

What exactly is lung fibrosis? It is described as excessive scarring in the lungs that includes accumulations of fibrotic tissue. The causes are stated as either environmental or disease but the word “idiopathic” often precedes the term descriptor which is described medically as either lung fibrosis or pulmonary fibrosis. The two are the same.

What happens when lung fibrosis occurs is the development of internal scarring leading to stiffened fibrotic tissue containing collagen, a connective tissue found in bones, cartilage, skin and elsewhere. When it builds up in the lungs they become less flexible and it is harder to breathe. At the same time, the condition reduces the oxygen-blood exchange to impact organs in the rest of the body.

The condition has been linked to smoking, rheumatoid arthritis, lupus, and radiation and chemotherapy treatment for cancer. Mesothelioma is linked to lung fibrosis with asbestos suggested as the causal agent. To date, there is no cure for lung fibrosis which eventually can lead to lung failure.

How many people suffer from lung fibrosis? According to the World Health Organization, there is a range of between 3.3 and 45.1 cases reported per 100,000 globally with incidents on the increase.

However, lung fibrosis can be managed as a chronic illness. That was the inspiration behind EMBL researchers setting out to find ways to control it by reexamining drugs and chemicals already in use. Among these were DXM and codeine with the former having fewer side effects.

Mujzamil Khan, one of the lead authors of the paper states the team used high throughput microscopy, an automated imaging technique that allows for the rapid analysis of large numbers of samples, to see how DXM inhibited fibrotic tissue formation. They learned the underlying mechanism and actions of DXM when introduced into the lung. Testing was done using a “scar-in-a-jar” approach with organotypic human lung tissue cultured in the laboratory. The encouraging results have led to plans for a future Phase 2 clinical trial with human volunteers.

So let’s give DXM its due. It’s not just the placebo as my family doctor has suggested. It is not my mind that makes DXM-containing cough syrups work for me when I get a respiratory infection with a bad cough. So much for the naysayers. DXM rules!