January 1998
NEW YORK - Many doctors believe that cough and cold products offer little more than a placebo, yet parents insist on using them, explained Ronald B. Turner, MD, at the 10th Annual Infectious Diseases in Children symposium.
"The first thing I think we need to recognize is that parents are already using these medications no matter what we say," said Turner, professor of pediatrics at the Medical University of South Carolina in Charleston. A national survey of mothers of 3-year-old children found that 54% of children had been given an over-the-counter (OTC) medication in a 30-day period; one-third had been given an OTC common cold medication in that same period; and 70% had been given an OTC medication for their most recent illness.
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Turner admitted that there is a lack of efficacy data for common cold therapies in children. However, he attributed this to a lack of pediatric studies. Common cold therapies can provide modest, short-term relief of specific symptoms, but combination products should generally be avoided unless all of the symptoms are present, he said.
Parents should be told, however, that there is no evidence that treating cold symptoms prevents otitis media, sinusitis or asthma. "So you cannot promise that you're going to prevent any of those things by treatment of the common cold," he said.
"It's not fair to ask that an antihistamine cure your cold. All you can ask is that it will reduce your sneezing and rhinorrhea," he said.
Since parents are giving these products to their children, it makes sense for pediatricians to make sure they are being used properly. "I think if we're going to use these medications, and I'm suggesting that they can be used, and perhaps, should be used, it's also important to keep in mind that there are some problems with the dosing of these medications by caregivers."
Tell parents which products are suitable for children and how to dose the medications correctly. "I think one of the things that we have to be careful of is if we're going to give a parent Dimetapp [Whitehall-Robins] or any other antihistamine or decongestant we need to make sure they know how to dose it," he said.
Several studies have demonstrated a positive effect of antihistamines on rhinorrhea and the common cold. In adults, studies show a 30% reduction in rhinorrhea with effective antihistamine therapy. "That's either a little or a lot depending on what you expect, but certainly it's not a dramatic relief of rhinorrhea with these medications," Turner said.
Of course, natural colds get better on their own, so placebos also work. Saline also reduces the severity of rhinorrhea by about 20%, he said. "So the placebo effect is certainly a very potent effect in the common cold. When you add a drug to that, you actually do get a little more benefit," Turner explained.
"The mechanism of action of antihistamines in treatment of the common cold is based on their anticholinergic effects," he said. "It's got nothing to do with their antihistaminic effects, and if you take a good antihistaminic drug that has no anticholinergic activity, there's absolutely no effect on rhinorrhea in the common cold compared to placebo. So, you need to have a sedating antihistamine if you're going to have any effect at all on the rhinorrhea."
When an anticholinergic agent like ipratropium bromide was compared with an antihistamine, the anticholinergic produced about a 30% reduction in both symptom score and nasal mucus weight.
Cough is a difficult issue with the common cold. Some of the possible mechanisms of cough in the common cold are bronchoconstriction and reactive airway disease. Studies suggest that cough in a cold is mediated by a cholinergic mechanism.
In a study that used a combination antihistamine decongestant, patients reported a statistically significant reduction in cough. A new study by Jack Gwaltney, MD, suggested that it may be the antihistamine rather than the decongestant that has the effect on the cough.
Dextromethorphan and codeine have been shown to reduce cough effectively in situations of chronic cough illness. However, the data is sketchier for coughs due to colds. The mechanism of cough is different for each type of cough.
"There has never been a study that I can find where dextromethorphan or codeine has been demonstrated to be effective for cough in acute illness in acute common colds. And so whether these drugs really have any effect in this syndrome, I really don't know," he added.
"It may be that we're putting a whole bunch of different syndromes of cough into the same basket and trying to treat it with one medication that may not be effective against that whole broad pathogenesis."
Patients with common colds from rhinovirus have cough more frequently than those who don't have rhinovirus isolated from the lower respiratory tract. Turner said cough suppressants might be a little more effective in that group.
Mildly ill children who have persistent cough following a cold may have sinusitis, and may need a course of antibiotics.
There are potential side effects with cough and cold products, and parents should be informed that these are not necessarily benign medications. With the topical decongestants, nasal irritation and rebound congestion are a big problem. "I think it's less of a problem in young children because they're not the ones that are dosing themselves; so in fact, the ability to go use these things inappropriately rests with the parents, and we can teach parents not to do that," he said.
Oral decongestants can cause cardiac and central nervous system effects. "These things do have effects elsewhere other than in the nose, and I don't particularly like them for that reason," said Turner.
Drowsiness is a side effect of antihistamines in adult studies. "For children, I would simply point out that this is a side effect if it occurs at 10:00 in the morning; it's a beneficial effect if it occurs at 10:00 at night," Turner said. "The sleep-inducing aspect of antihistamines may be beneficial in some situations. But I think it is inappropriate and a problem to give children an antihistamine at 8:00 in the morning and then send them to school and expect them to perform well."
Other side effects of antihistamines include dry nose, dry mouth and urinary retention. Ipratropium has been associated with nasal dryness and blood tinged mucus, but there have been no serious systemic effects associated with the use of this medication.
Turner ran down the list of medications he would consider to treat various symptoms. "First of all, for nasal obstruction I recommend topical adrenergic agents. There's absolutely no question that they're effective. The oral adrenergic agents are also effective, but less so, of course, than the topicals," he said.
Cromolyn is now available OTC and is increasingly being used for common cold therapy. There is no evidence that mast-cell degranulation has anything to do with the common cold, and this medication is not effective for that purpose.
For rhinorrhea, either with antihistamines or with ipratropium, there is a 30% reduction in rhinorrhea - so it's not a dramatic effect but it's a real, reproducible effect.
Standard antipyretic analgesic therapy is effective for sore throats. "I should mention that in at least one study, antibody responses to the common cold viruses have been found to be blunted by treatment with these medications. The clinical significance of that is not clear, but it's something that we should pay attention to," he said.
Bronchodilators are useful for patients who have reactive airway disease; and antibiotics may help patients with sinusitis.
Turner predicted that future colds will be treated with some type of anti-inflammatory therapy probably directed at the cytokines.
For more information:
- Turner RB. Effective management of the common cold. Presented at the 10th Annual Infectious Diseases in Children Symposium. Nov. 22-23. New York.
- Gwaltney JM, Jr. (1990). The Common Cold. Principles and Practice of Infectious Diseases. New York, Churchill Livingstone Inc. 3rd ed. 489.
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