Do cough medications work?

Source: Best Health Magazine, January/February 2010

Lately there has been confusion about how much over-the-counter (OTC) medications can do (although clearly, Canadians do believe in them: We spend more than $80 million on them annually).

Why we cough

Most respirologists say coughing is a good thing. ‘It’s a natural reflex to clear noxious irritants and secretions, such as mucus (or phlegm), from the airways,’ says Dr. Andreas Freitag, an associate professor of medicine and pediatrics at McMaster University. A cough is classified as acute (usually dry in nature and caused by a viral infection) if it lasts one or two weeks; check with your doctor if it lasts longer than two weeks.

Viral infections can lower one’s immunity, explains Dr. Brian Levine, medical director of The Cough Center in Laguna Hills, Calif. As a result, following a viral infection many people come down with a bacterial infection, such as bronchitis or pneumonia, and an antibiotic may be prescribed. Usually, the cough becomes wet sounding and ‘productive’ (bronchial secretions are brought up in the throat) with a fever. Seek medical care if you have a productive cough.

A cough classified as chronic, as with acute coughs, is usually dry and not productive, and lasts for more than one month. It can be due to a combination of causes, including asthma, allergies, post-nasal drip, acid reflux and certain medications. Doctors say there are not any long-term health implications if you do not treat it, but there are consequences of severe coughing, such as pulled muscles and broken ribs. An untreated cough can also keep you awake, leading to fatigue and other health issues, so it’s important to get relief from a cough even if it is temporary. Depending on the cause, chronic coughs are usually treated with inhaled anti-inflammatory drugs, topical decongestants, nasal saline solutions or anti-reflux medication.

How cough medicines work

OTC cough medications claim only to provide relief from symptoms. ‘There are two major types of OTC medications,’ explains Andrew Leeds, a pharmacist and lecturer in the department of clinical pharmacy at the University of California San Francisco:

‘ Cough suppressants contain the drug dextromethorphan, which helps reduce the need to cough, Leeds says, by acting on receptors in the brain. (They include Vicks Custom Care Dry Cough, Robitussin DM CoughGels, Triaminic Long Acting Cough and Buckley’s DM.)

‘ Expectorants thin out secretions in the respiratory tract, usually via the drug guaifenesin, so they can be coughed up more easily, says Leeds. (They include Benylin’s Mucous and Phlegm Relief, and Balminil Expectorant.)

Some experts say OTC cough medications don’t work…

Clearly, for millions of Canadians these options help relieve symptoms, although when it comes to the frequency or severity of acute coughs, a recent review of 25 trials found no evidence for or against the effectiveness of OTC medications. Other research suggests that much of their impact is a placebo effect. A study led by Ronald Eccles, at the Common Cold Centre at Cardiff University, United Kingdom, found that in people taking cough suppressants, 85 percent of symptom relief is because they believe the treatment will be effective; the rest relates to the active ingredient itself. (No strong proof exists on whether expectorants are more effective than a placebo.)

…while others say they do

However, Gerry Harrington, director of public affairs for Consumer Health Products Canada‘an organization representing manufacturers of non-prescription meds and natural health products’is confident cough medicines do alleviate symptoms temporarily, and says the latest research is flawed. He explains that when dextromethorphan was approved in the 1950s, trials were done on patients with artificially induced coughs, and the drug was proven effective. But more recent studies exclude this methodology in favour of people who already have a cold. Harrington says factoring in the cause of a cough is irrelevant, since ‘these products are not positioned as providing anything but symptomatic relief [for the cough]. We know there’s no cure for the common cold and that cough medicines are not antivirals.’

Harrington also says it’s not surprising that newer trials suggest cough medicines are no better than placebos. ‘By day four or five of a cold’usually the point when patients can be enrolled in a trial’both the placebo and drug groups are quickly getting better,’ he says. ‘So it’s very difficult to measure a significant difference between their outcomes, which is how we prove efficacy.’

Other drugstore cough remedies include:

‘ Formulas with codeine, a narcotic present in certain cough medicines, such as Benylin Cold & Flu with Codeine (kept behind the counter at most pharmacies, although you don’t need a prescription). It works by suppressing the cough reflex, but comes with side effects, including drowsiness and gastrointestinal upset. If misused, codeine can also be addictive.

‘ Decongestants that work by narrowing the blood vessels in the nasal passages and drying out mucus secretions (such as Sudafed 12 Hour Decongestant and Tylenol Sinus Pain and Congestion, which contain pseudoephedrine). This can be helpful if your cough is caused by post-nasal drip. (They are usually marketed for allergy-related symptoms.)

‘ Some antihistamines will dull the cough reflex if it’s triggered by allergies (like Benadryl Allergy, which contains diphenhydramine). They block the effect of histamines’the chemicals we produce in response to an allergic reaction. Side effects can include drowsiness, dizziness and hallucinations.

Home alternatives

‘ Some experts recommend home remedies for adults and kids. ‘If you have a productive cough, the best expectorant is water,’ says Leeds. ‘Staying hydrated helps you cough up mucus.’ Also, green tea and hot chocolate contain a substance called theobromine, which suppresses coughs similar to codeine.

‘ Adding just a few drops of eucalyptus or peppermint oil to a steam vaporizer can help open airways and decrease tightness in the chest, and irrigating the nasal passages with a neti pot and saline rinse decreases mucus secretions.

‘ For more natural treatments, check out 1.801 Home Remedies (Reader’s Digest)’available in the Best Health Shop now!

This article was originally titled "Cough medications: Are they effective?" in the January/February 2010 issue of Best Health. Subscribe today to get the full Best Health experience’and never miss an issue!’and make sure to check out what’s new in the latest issue of Best Health.