The cold season has arrived, a cure hasn't, and even efforts at treating the symptoms seem like a dubious proposition these days.
Over-the-counter cold remedies have come under harsh scrutiny lately. In October 2007, an FDA advisory panel recommended a ban on cold medicines for children under six, and in anticipation of that vote, several drug makers pulled their infant cold medicines off the shelves. Medicines for adults weren't affected, but they don't have a track record that inspires great confidence. Little wonder, then, that people have sought out alternatives like vitamin C and zinc. But for the most part, the evidence for them is pretty shaky.
Here's a rundown on cold treatment and prevention:
Over-the-counter medicines. Colds, of course, have a variety of symptoms, so cold medicines have a variety of ingredients: almost always some kind of pain and fever reducer, usually acetaminophen; a cough suppressant, often dextromethorphan; a nasal decongestant, usually phenylephrine; and sometimes an antihistamine, often chlorpheniramine.
Do these concerns about infant and children's cold formulations apply to the adult medicines? Efficacy is certainly an issue. British researchers reviewed 15 trials of cough medicines and concluded that "there's no good evidence of their effectiveness."
If taken at the recommended dose, the OTC medicines are reasonably safe for adults. Still, that's a sizable if. Most of the complications from the infant and children's formulations have come from accidental overdoses, which can be a problem for adults, too. People may not realize, for example, that a tablespoon of Nyquil contains 500 milligrams (mg) of acetaminophen. If they are taking lots of Tylenol — which is acetaminophen — at the same time, they can get into trouble.
Pseudoephedrine, the active ingredient in stand-alone nasal decongestant products like Sudafed, works by constricting nasal blood vessels, but that effect isn't limited to the nose. Pseudoephedrine can cause hypertension and, rarely, cardiac arrhythmias and strokes, as well as urinary retention in men with an enlarged prostate gland.
Vitamin C. In 2007, a review of 30 trials that included a total of over 11,000 people found that taking the vitamin to prevent colds had little, if any, effect. Exceptions might be people who engage in heavy-duty exercise like marathon running or who are exposed to extreme cold. Such experiences cause temporary dips in immune function that vitamin C may offset.
Zinc. Taking zinc has been proposed as a way to shorten colds and perhaps reduce their severity. Stanford researchers reported in 2007 that three of four studies that they identified as being the most reliable didn't find a therapeutic benefit from zinc lozenges or nasal spray. The fourth, which tested a nasal gel, did. There have been several reports, though, of zinc gels causing a loss of the sense of smell that can last more than six months.
Echinacea. In a meta-analysis of 14 studies, University of Connecticut researchers found that taking echinacea decreased the odds of developing a cold by 58% and the duration by 1.4 days. The results, reported in 2007 in Lancet Infectious Diseases, were a bit surprising because a number of randomized clinical trials, including two funded by the National Institutes of Health, hadn't found any benefit from taking echinacea.
Prevention that works
Regular handwashing really is one of the best cold protection tactics around. Exercising very hard may temporarily lower your immunological guard, but regular, moderate exercise boosts the immune system, and some research suggests it could prevent colds. Vitamin D may also help fend off colds by boosting the immune system. But don't go overboard. The safe daily upper limit for vitamin D is 2,000 International Units.
And once you get a cold...
Cold medicines aren't the only OTC game in town. You can take many of the ingredients contained in these medicines separately, which allows for a targeted rather than a shotgun approach to symptoms. Aspirin or acetaminophen can ease the pain of a sore throat. Nonsteroidal anti-inflammatory drugs like naproxen (Aleve, other brands) can help with a cough.
Taking a decongestant isn't the only way to open up nasal passages. Inhaling steam from a teakettle or in a hot shower can help. Drinking plenty of water helps unplug nasal passages by keeping mucus moist and flowing. And if you have a fever, fluids counteract the tendency to get dehydrated.
Finally, don't overdo the nose blowing. Too much blowing can push nasal fluids laden with bacteria and viruses into the sinus cavities. The result in some cases is a secondary infection of the sinuses that needs to be treated with antibiotics.February 2008 update