Can medicines relieve coughing?
© 2016 Roy Benaroch, MD
Wzrd1 asked, “What are your thoughts on expectorants?”
One of the most common reasons for office visits to me, especially in the winter, is coughing. No one really likes to cough – not the kids, and certainly not their parents. Everyone wants the coughing to stop.
First, though, think about what a cough is – it’s a forceful pop of an exhale that can bring up mucus from the airways. If you’ve got a cold with excessive mucus, or you’ve inhaled some dust, or there’s a bacterial infection with pus down in your lungs, the only way to get that stuff out is to cough it up (and, typically, swallow it back down into your stomach. From there it can be digested on its way out of your body. Isn’t science fun?) The alternative to coughing is to just let the yuck sit down there. Coughing has a purpose, and it’s a good thing.
Yeah, I know. Try telling that to a parent or child at 2 AM. Besides, no one wants a coughing person at school or at work, spraying their mucus around. I get it. So it sure would be nice to have something, anything, to at least slow that cough down some.
Now, if your child has asthma or cystic fibrosis or some other lung thing, it’s best to treat the underlying cause of the cough. For the rest of this post, I’m talking about only non-specific, mild, ordinary coughing. The kind that goes with an ordinary “cold” or “chest cold” or “bronchitis” (which, by the way, are all the same thing. But that’s a topic for another time.) If your child has a cough with a high fever or trouble breathing, or has chronic lung problems or heart disease, go get it checked out.
Most of the time, though, a cough is just a cough. Medicines available to help with cough fall into just a few categories:
Cough suppressants, like dextromethorphan (OTC) or the narcotic codeine (Rx). These either make you too sleepy to cough, or somehow “suppress” the cough centers of your brain to trick you into not coughing. Stronger ones, like codeine and similar compounds, can cause respiratory depression and death, which is bad.
Expectorants, like guaifenesin (OTC). These supposedly “thin the secretions”, making them easier to cough up. Sometimes, expectorants and suppressants are combined into one product, which I suppose makes it easier to cough while simultaneously stopping your cough. Honestly, I get a headache just thinking about why that would be a good idea.
Antihistamines, which block many allergic reactions. These will help if a cough is caused by allergy (clue: if there is also runny/itchy eyes and nose, that might be the case.) Older antihistamines like Benadryl also make people sleepy, so they won’t notice the cough. Maybe that’s good.
Do these medicines work? There are dozens of studies out there, using a variety of doses and ways to measure coughing. The bottom line, summarized here, is that better-quality studies with more-objective measures of coughing and appropriate use of placebo comparators have not consistently shown any effectiveness for any “cough medicine”, used alone or in combination. And there have been significant side effects, especially from antihistamines and narcotic-based cough suppressants.
About expectorants specifically: basic science studies, like this one, have failed to show that expectorants change the way mucus appears or is cleared by cilia. And clinical studies from the 1980’s showed no change in objective or subjective cough scores. There have been zero—zero!—good quality studies of expectorant use in adults or children for coughing in the last 20 years. I did find one case report of a man who had improved sperm motility when he was treated for infertility with guaifenesin, but I don’t think that’s exactly what most parents are looking for.
In fact, the only positive news about cough treatment I found in the recent literature was in support of honey for the relief of coughing in children one year and up. Three good randomized trials have been published in the last few years, all showing that honey is better than either placebo or “cough medicine”. We’re not talking honey-based “medicine”, here – that’s for sale, but you don’t need it. Just good old honey, typically from a bottle shaped like a bear. It works, it’s cheap, it’s safe for children 1 year and up. Give it a try. And teach your children to cough into their elbows. That’s honestly the best you can do.