This video explains why cough medicines don’t work. The whole 6 minutes is worth a look, but you can skip to the 2:00 mark on the video to see an animation of mucociliary clearance.
Cilia are the tiny hair-like projections that line the lungs and airways. They beat together in waves to move mucus out of our lungs. When we are healthy, don’t smoke and breath unpolluted air, the cilia work great. The mucus secreted by our airways traps viruses, bacteria, air pollution, allergens and dead cells, sweeping them quietly up to the top of our throat to be swallowed with salvia. Think of it like a tiny escalator.
Infections and irritants damage the cilia. Their beautiful wave-like movement stops. The protective mucus inside the lungs builds up–along with all the extra mucus that colds and pollen and pollution trigger. To clear the mucus, you have to manually clear the lungs. In other words, you have to cough. Watch the video on cough here.
Over the counter cough medicines don’t work because they can’t get the cilia working again. They are sold to suppress cough, and cough suppressants don’t work because they tell the brain, “Hey, don’t cough.” Your lungs, faced with this build up of mucus, are going to cough because cough is a primitive, protective reflex. If you didn’t cough, your lungs would fill up with mucus and there would be no place for the air to exchange oxygen for carbon dioxide.
To suppress cough, you need to heavily sedate the patient, but too much sedative and the patient doesn’t breath. This can happen when people consume too much alcohol or other sedatives.
Doctors suppress cough in a very controlled manner for patients getting general anesthesia or when patients are on a ventilator. The risk to these patients, however, is pneumonia because sedation eliminates the protective cough reflex.
To treat cough, doctors need medicines that repair the waving cilia or we need ways to prevent patients from becoming sick with the infections that do the damage.