No coughing matter

The cough is one of our basic defense mechanisms. This reflex and that unceremonious expulsion of air, mucus, and microbes spares us all sorts of infectious and inflammatory pulmonary misadventures.

But who hasn't had too much of a good thing? So we make 30 million trips to the doctor each year seeking relief from coughs and spend roughly $3.5 billion annually on over-the-counter (OTC) pills, capsules, and syrups for cough- and cold-related woes.

Experts say much of that is wasted money. According to guidelines released by the American College of Chest Physicians in early 2006, many of the "active" ingredients in famous OTC cough remedies like Robitussin and Vicks Formula 44 are ineffective. You'd be better off taking an early-generation antihistamine and a nasal decongestant, said the experts.

A multitude of causes

While coughing exists to protect us from infections of the respiratory tract, it is commonly found with other conditions, too. We associate asthma with wheezing and difficulty breathing, but for many, its main symptom is a cough. Heartburn is the cardinal symptom of gastroesophageal reflux disease (GERD), but the stomach acid can also produce a nasty cough.

Coughing is also a side effect of several drugs, most notably ACE inhibitors (Capoten, Prinivil, Vasotec, other brands), which are mainstays in the treatment of high blood pressure and heart failure. Chronic obstructive pulmonary disease (COPD), bacterial sinusitis, lung cancer — all may announce their presence with a cough. But among nonsmokers, the most common cause of a cough is the common cold. When cold-causing viruses take up residence in the nose and upper respiratory tract, the tissue lining those cavities produces mucus.

Choices, choices, choices

OTC cough and cold medicines come in a number of varieties. It may be a little easier to make a choice if you realize that most of these products contain the same few active ingredients, in a limited number of strengths and combinations. Here's a rundown of the five main types of ingredients:

Expectorants. These work chiefly by affecting the production, consistency, and clearance of mucus in various ways. Guaifenesin (pronounced gwy-FEN-e-sin) is the most common OTC expectorant. The cough guidelines cite studies showing that guaifenesin is effective, but also point to others showing that it's not. Some of the positive results test doses larger than those commonly used in OTC products (400 mg versus 200), although there are OTC products like Mucinex that contain larger amounts (600 mg per tablet). Want a free, reliable way of loosening mucus? Just try drinking plenty of water.

Suppressants. These work by suppressing the cough reflex in the brain. Dextromethorphan (pronounced dex-tro-meth-OR-fan) is the most common. The good news: they provide short-term relief for chronic bronchitis symptoms. The bad news: These drugs have "limited efficacy" when it comes to coughs caused by colds.

Decongestants. These work by constricting blood vessels, which allows more air to pass through nasal passages. As a result, tissues dry out so there is less postnasal drip. Pseudoephedrine (pronounced sue-doe-e-FED-rin), the active ingredient in Sudafed, and phenylephrine (pronounced fen-ill-EF-rin) are the most common decongestants. Decongestants can be wonderfully effective in the short run but they also present problems. You can become dependent on nose drops like Afrin if you use it for more than four consecutive days. Pseudoephedrine has many potential side effects ranging from wakefulness to increased blood pressure to an irregular heartbeat. Take the warnings seriously.

Antihistamines. If hay fever or allergies are the cause of the congestion and cough, antihistamines can block the histamine that causes the allergy sufferer's runny nose and watery eyes. Histamine isn't involved in symptoms of the common cold, but the older antihistamines like brompheniramine and chlorpheniramine decrease the secretion of mucus and widen airways. Newer non-sedating antihistamines, like loratadine (Claritin) aren't effective as cough suppressants.

Analgesics or pain relievers. Many OTC cold medications contain acetaminophen, the active ingredient in Excedrin and Tylenol. The danger is that some people may not realize that cold and cough concoctions contain acetaminophen. If they then take Tylenol or Excedrin as well, they could be risking liver damage and even death from too much acetaminophen.

So what should you take?

For your everyday cough from a common cold, the new guidelines advise taking one of the allergy medicines that combine an older antihistamine and a decongestant. The guidelines also say that naproxen (Aleve) might be helpful. But these are just guidelines. The studies they're based on can't possibly reflect every individual experience. But, if you have a cough that you just can't shake, see your doctor.

June 2006 update