Capsules, liquid cough syrups and cough drops are all examples of cough medicines. Some medicines are only available with a prescription; others are over-the-counter (OTC) and some are sold behind-the-counter. Making sense of the myriad choices available to treat coughing can seem daunting, especially since most OTC cough medicines don't work.
Cough Suppressants vs Expectorants
One of the most confusing things about cough medicines is understanding the difference between cough suppressants and expectorants. Cough suppressants are supposed to do just that: suppress coughs. Expectorants, on the other hand, are supposed to make coughing more effective by increasing mucous production in the lungs and airways. Some medications purport to both suppress coughs while still increasing the mucus that makes you want to cough in the first place, which never made much sense to me.
There is a growing body of evidence that cough suppressants don't work. There is also a somewhat scary list of side effects and adverse reactions to the most commonly used cough suppressants. The FDA strongly advises against giving cough suppressants to kids under 2 years old and may increase that to kids under 6 years old. Cough suppressants, however, don't work any better in adults than they do in kids. It's probably a good idea to stay away from cough suppressants entirely unless your doctor specifically tells you otherwise.
Coughing is a complicated response to various factors, such as irritants, inflammation, mucous production and food or fluid in the airways. Suppressing a cough is not as easy as it sounds. The only surefire way to cure a cough is to get rid of whatever is causing it.
Coughs from Allergies
If an allergic reaction is to blame for your cough, the best medicine will be an antihistamine. The oldest and most popular antihistamine currently available is Benadryl. Often, allergic reactions will have sneezing, itching and watery eyes in addition to a cough. Antihistamines aren't technically considered cough medicines, but they may be useful if an allergy is the culprit.
A note of caution about antihistamines: they can make you drowsy. Benadryl makes you so drowsy it is sold as a sleep aid. Look for nondrowsy antihistamines. Ask your pharmacist to clarify side effects. Coughing due to asthma needs to be treated according to your doctor's orders.
Coughs from Infections
Infections can cause cough by increasing mucous or by causing swelling and inflammation in the nose, throat, windpipe and bronchi. Croup is an example of a cough from a viral infection, but bacterial infections can cause coughing as well.
Bacterial infections can sometimes be treated with antibiotics, but usually your body beats the infection before your doctor will get you in to the office.
Viral infections don't get any better with antibiotics, and antiviral medications can be hard on the body. For that reason, doctors don't give antiviral medications for common colds. Your doctor may prescribe an antiviral medication for the flu if you come in early enough.
Infections that lead to runny noses can cause cough. When mucus from the nose -- commonly called "snot" -- drains back to the back of the throat and irritates the vocal chords, a cough is born. Medicines that clear up stuffy noses -- decongestants -- can sometimes help with this type of cough.
Pneumonia and Bronchitis
Two types of lung infection, pneumonia and bronchitis, produce lots of mucus in the lungs. This mucus traps bacteria and small particles and is transported up to the throat by by microscopic fingers on the walls of the airways. Once at the throat, mucus from the lungs has to be cleared by coughing. This is where expectorants come in handy.
Expectorants will increase the production of mucus and make it more effective. The extra mucus helps clear the infection quicker. Cough suppressants don't work, but expectorants do.
Many cough medicines contain more than one active ingredient. In other words, the liquid you're drinking or the capsule you're swallowing may have an antihistamine, a decongestant and a cough suppressant. Most flu and cold medications list coughing as one of the symptoms they treat and may have active ingredients that are the same as drugs sold specifically for cough.
Combination medicines such as these can lead to problems when treating yourself or your family. Taking one medicine for cold symptoms and another to treat cough could can lead to an accidental overdose of cough medicine. Some cough medicines have significant and potentially dangerous side effects that could be much worse in an overdose. So don't take extra cough medicine if you're taking a medication that covers multiple problems, such as sniffling, sneezing, coughing, etc.
There are lots of home remedies for cough, but the only one that seems to work is honey. While not a medication, honey actually did a better job than honey-flavored dextromethorphan, a cough suppressant, in one study. Read more about honey and cough to learn about the research.
Of all the other home remedies you may have heard about, one common myth should be put to rest right here: Humidity -- moist air -- doesn't do anything to alleviate cough, despite the fact that healthcare providers have spent decades recommending humidity as a treatment for croup.
Home remedies are often based on practices that work better than nothing at all. Sometimes, such as with croup, the treatment may work for an entirely different reason than we thought. Sometimes, it's all in our heads. Be willing to try things at home, but don't ignore significant illnesses. Always call 911 or go to the emergency department for victims of shortness of breath, regardless of the cause.
Bolser, D.C. "Cough suppressant and pharmacologic protussive therapy: ACCP evidence-based clinical practice guidelines." Chest. Jan 2006
Pratter, M.R. "Unexplained (idiopathic) cough: ACCP evidence-based clinical practice guidelines." Chest. Jan 2006