Treating colds: What works, what doesn't

If you’re a typical adult, every year you catch two or three colds. The virus that causes the common cold can only hurt you if it gets into your nose, either directly or via the tear ducts in your eyes. So unless someone has sneezed near you, your own (contaminated) hands are probably to blame. (Your mouth is innocent. In a 1984 study, participants were unable to transfer the virus by kissing.)

Once the virus hits the back of your nose, it begins multiplying. Symptoms appear within 10 to 12 hours, peak at one and one-half to three days, and are generally gone within a week. How can you protect yourself? “Keeping your hands clean is one of the most important steps to avoid getting sick and spreading germs to others,” says the US Centers for Disease Control and Prevention in Atlanta. Just don’t assume you’re safe if you haven’t been near someone who has a cold. Researchers have found live cold viruses on hard surfaces in a hotel room up to 24 hours after cold sufferers checked out.

What Works

So what’s the best way to treat a cold?

“At the very first hint that a cold is starting, take a first generation antihistamine and a nonsteroidal anti-inflammatory drug (NSAID) every 12 hours and keep taking them even if you feel better,” says cold expert Jack Gwaltney, MD of the University of Virginia. “That won’t stop the cold, but it will lessen the symptoms.” Adds Dr. Gwaltney, “But if your cold isn’t better after a week, check with your doctor to make sure you haven’t developed a secondary bacterial infection. That happens in about one in 50 colds.”

Here’s our adaptation of Dr. Gwaltney’s full prescription, which is based on the results of a half-dozen good studies:

1. Begin treatment at the earliest sign of a cold.

2. Take a sustained-release first generation antihistamine (the kind that can make you drowsy) like diphenhydramine (Benadryl), chlorpheniramine (Chlotrimeton in the US), brompheniramine (Dimetapp), or clemastine (Tavegyl; Tavist). Newer, non-sedating antihistamine like fexofenadine (Telfast, Allergan in the US) and loratidine (Claritin) don’t appear to be as effective.

3. At the same time, take an NSAID like aspirin, ibuprofen (Alaxan, Advil, Motrin) or naproxen (Naprosyn, Aleve in the US).

4. Continue taking the antihistamine and NSAID every 12 hours until the cold symptoms clear (three to seven days).

5. If your stuffy nose or cough doesn’t seem to be getting better, add an oral decongestant like pseudoephedrine (Sudafed) and a cough suppressant like dextrometorphan or DM (Robitussin Cough DM).

6. If you feel worse or no better after seven to 10 days, see your doctor. You may have developed a bacterial infection.

What Doesn’t

But what about popular remedies that are being used by millions around the world to treat colds? Do they work? Here’s the scoop on some of the most frequently-sold over-the-counter cold products.

Vitamim C

• Claim: “Vitamin C can prevent colds,” says the alternative medicine site on the New York Times-owned www.about.com.

• Evidence: “Vitamin C does absolutely nothing to prevent colds in most people,” says Robert Douglas, MD of the Australian National University in Canberra, who reviewed the evidence for the Cochrane Collaboration in 2004. Cochrane Collaboration is an international network of scientists who review and evaluate medical research. In 29 studies of more than 11,000 people, 200 mg. to 2,000 mg. a day of vitamin C (most people took 1,000 mg.) didn’t ward off colds. What about those who go sick despite taking vitamin C regularly? In 30 studies in which people got some 10,000 colds, vitamin C cut about half a day off the typical five days they missed work or school, notes Douglas. It also curbed their coughing and other symptoms slightly. But when people started taking vitamin C only after they got sick, their colds were neither shorter nor milder.

• Bottom line: Vitamin C does not prevent colds. But taking roughly 1,000 mg. a day before and while you’re sick may make your cold milder and shorten it by half a day or so.

Echinacea

• Claim: “The world’s best-known herb for supporting the body’s defense system,” says supplement manufacturer Natrol.

• Evidence: Can taking echinacea protect you from catching a cold? No, according to a 2006 review by the Cochrane Collaboration. In the three trials that gave people echinacea for eight to 12 weeks, the herb was no better than a placebo at preventing colds. But the leaves and flowers of one strain of echinacea (purpurea) “might be effective” at treating colds, though the research is “not fully consistent,” concluded the Cochrane reviewers after examining the results of 14 trials. In seven of the 10 trials that used purpurea, volunteers had shorter or milder colds. That was true in only one of the four trials that used other echinacea strains or mixtures of strains. “The more recent, better-designed studies tend to find that echinacea doesn’t work,” notes researcher — and Cochrane reviewer — Bruce Barrett, MD of the University of Wisconsin in Madison. “Or it’s possible that echinacea has only a very small positive effect that some studies will pick up on and others won’t, depending on how they’re designed.”

• Bottom line: Taking echinacea regularly won’t keep you from getting a cold. But starting it at the first sniffle might help dry up your runny nose or relieve other symptoms. The best evidence is for supplements made from the purpurea strain.

Cold-Eeze

• What’s in it?: 13.3 mg. of zinc gluconate glycine in each lozenge.

• Claim: “Clinically proven to cut colds by nearly half.”

• Evidence: In the mid-1990s, Cold-Eeze’s manufacturer funded two studies at the renowned Cleveland Clinic. In one, 99 staff members took Cold-Eeze or candy lozenges every two hours while awake for as long as they felt sick. It took about four days for all the symptoms to disappear in half of the zinc takers, versus about seven days in half of the placebo takers. That’s a difference of 43 percent in the length of colds, which is where the company gets its “cut colds by nearly half” claim. But when the same researchers repeated the study with 249 children and teenagers, Cold-Eeze had no effect on either the length of colds or any symptoms. The company hasn’t published any good studies since.

• Bottom line: “Clinically proven to cut colds nearly half”? Only if you ignore one of the two good studies.

Airborne

• What’s in it?: A mixture of 17 vitamins, minerals, and herbs, including megadoses of vitamin A and C.

• Claim: “Boost your immune system to help our body combat germs.” “Take at the first sign of a cold symptom or before entering crowded, potentially germ-infested environments.”

• Evidence: This popular cold remedy, which sold an estimated $300 million in the United States last year, was created by a former California second grade teacher. Victoria Knight-McDowell has said she invented Airborne 11 years ago because she was tired of constantly catching cold from her students. Apparently, she hasn’t gotten tired of having no credible evidence that Airborne works. According to the company, a study it funded several years ago showed that Airborne relieved cold symptoms faster than a placebo. But Airborne won’t make the study public. And a February 2006 investigation by ABC-TV discovered that the company that carried out the study, GNG Pharmaceutical Services, is “actually a two-man operation started up just to do the Airborne study.” As ABC reported, “There was no clinic, no scientists, and no doctors.” If Airborne has any impact on colds, its high dose of vitamin C — 1000 mg. per tablet — might be the reason. That much vitamin C may slightly reduce the length and severity of colds. But you can easily buy 15 vitamin C pills for the price of one Airborne tablet. As for taking Airborne to repel germs in an airplane, restaurant, or other crowded environment, “that’s nonsense,” says cold expert Dr. Jack Gwaltney. “Nothing you can swallow can do that,” he adds,

• Caution: Each Airborne tablet contains 5,000 IU of the retinol form of vitamin A. Use two and you’ll hit the Tolerable Upper Intake Level — the largest amount of retinol that can be taken every day for months without risking liver damage, birth defects, and increased risk of hip fractures. Follow the package directions and you’ll be taking 10,000 IU every six hours.

• Bottom line: There’s no good evidence that Airborne can protect you from catching a cold.