How Are Cough Suppressants Different than Expectorants?

Two Medicines for Coughing with Two Very Different Functions

Doctor listening to patients cough
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Cough suppressants (also known as antitussives) are supposed to help control coughing by decreasing the urge to cough. Expectorants actually make you cough more. They promote more mucous production to make coughing more effective at removing bacteria.

Whether you need a cough suppressant or an expectorant depends on the type of cough you have. Coughs that produce mucous or phlegm are helping your body's immune system fight an infection and should be encouraged with an expectorant.

 

An expectorant's increased mucous production is going to help get rid of the bad stuff in your lungs (allegedly), but the extra dripping and irritation might not be worth it. It could even lead to increased inflammation that encourages more dry coughing.

Dry coughs that do nothing but keep you awake at night don't benefit from—or react to—an expectorant. For those coughs, you can try a cough suppressant. However, there isn't any evidence that clearly shows that suppressants help at all.

Suppressants Don't Work

There are lots of cough suppressants on the market. Most of the cough syrups sold over the counter haven't been shown to work. Honey works a little, but the urge to cough is such a complicated process that researchers are still trying to find a medicine that will truly suppress coughs.

Some coughs are caused by mucous draining from the nose into the back of the throat. An expectorant encourages the mucous production and improves the effectiveness of the cough, but the extra drainage might be lead to more coughing while laying down.

If sleep is important (and most doctors encourage plenty of rest when you're fighting an infection), then taking something that makes it harder to sleep might not be the best option.

Coughs due to mucous might be reduced by the use of an antihistamine with a decongestant. They don't do anything about your cough per se, but they stop the mucous from dripping back there and tickling your throat—which should give you some relief.

The problem with antihistamines and decongestants is that they can cause anxiety. Since nasal drip is a nighttime problem, taking the drugs to help you sleep could backfire, stopping the drip but keeping you up anyway. You just can't win.

For really irritating coughs, or coughs that last more than three days, your doctor may be able to prescribe a stronger cough suppressant. More importantly, seeing the doctor for a persistent cough could identify the underlying cause, which is the only real way to fix a cough.

Sources:

Gardiner SJ, Chang AB, Marchant JM, Petsky HL. Codeine versus placebo for chronic cough in children. Cochrane Database Syst Rev. 2016 Jul 13;7:CD011914. doi: 10.1002/14651858.CD011914.pub2. Review.

Holzinger, Felix C. (2014). The Diagnosis and Treatment of Acute Cough in Adults. Deutsches Ärzteblatt International111(20), 356. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4047603/

Smith SM, Schroeder K, Fahey T. Over-the-counter (OTC) medications for acute cough in children and adults in community settings. Cochrane Database Syst Rev. 2014 Nov 24;(11):CD001831. doi: 10.1002/14651858.CD001831.pub5. Review.

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