OTC COUGH/COLD PRODUCTS IN PRESCHOOL CHILDREN: FURTHER STUDIES

OTC COUGH/COLD PRODUCTS IN PRESCHOOL CHILDREN: FURTHER STUDIES are required "to clarify the role of these medications in children," two Canadian researchers conclude in an article published in the May 5 Journal of the American Medical Association. The two researchers, Michael Smith, Children's Hospital, Halifax, Nova Scotia and William Felman, MD, Hospital for Sick Children, Toronto, conducted a literature review of all published studies on OTC medications between January 1950 and January 1991 that were written in English. While OTC cold medications "form a common part of everyday medical therapy," the researchers stated, the "data on their effectiveness are limited and weak, especially for children." To arrive at their conclusions, Smith and Felman reviewed the Medline database for articles that described a controlled clinical trial on the treatment of the common cold. Each article was scored on 11 criteria to determine scientific validity; articles scoring above 70% were included in the analysis. Of the 55 studies examined, the researchers found only four that addressed the pharmacological treatment of colds in children. One study on preschool children found "no benefit in treating with an antihistamine unless a child had copious nasal discharge," the researchers said. Another study on preschoolers determined that "there was no clinically significant improvement in symptoms after 48 hours of therapy in an antihistamine-decongestant combination." The other two studies focused on older children. A British study compared two combination drugs in children aged six to 12. "Both groups showed a significant reduction in cough, sore throat and ache. Both combination medications contained analgesics," Smith and Felman said. A second European study examining children over four years found that an antihistamine-antitussive combo was "superior to an antihistamine expectorant combination," the Canadian researchers noted. Smith and Felman emphasized that for both child and adult populations, "clearly, there is a need for carefully designed randomized trials that concentrate on clinically useful benefits, such as reduction of cough or nasal discharge." Attention also "should be focused on appropriate dosing and potential side effects in different age groups," the two researchers suggested. In general, they recommended that "pharmaceutical firms . . . be urged to support this type of research that reaches peer-reviewed journals and contributes to the improvement of clinical therapeutics." The JAMA article found, however, that "the effectiveness of OTC medications is much more apparent in the adult and adolescent studies." Among antihistamine studies, the authors discovered that three of four chlorpheniramine studies showed a reduction in sneezing, nasal mucus amount or symptom score; the fourth showed no benefit. Diphenhydramine was not shown by published data to "be better than placebo in relieving the symptoms of a cold," the researchers said, and triprolidine was "also no better than placebo in treating nasal symptoms in a trial that also evaluated a combination medication." Studies on thonzylamine, an older antihistamine, also concluded that there was no symptom improvement. Of five decongestant studies, oral pseudoephedrine was found in two trials to spark a "dramatic reduction in nasal symptoms including congestion and sneezing." Nasal spray tramazoline produced no reduction in nasal discharge amount, while oxymetazoline improved "nasal patency and symptom scores," Smith and Felman stated. Phenylpropanolamine improved nasal patency during a four-hour period. They added that drug-related side effects occurred in 30% of treated subjects in one study; the remaining studies did not address side effects. Six of 12 articles on combination cough/cold product use by adolescents and/or adults suggested a reduction in symptoms such as decreased congestion, cough and ear problems. One study in particular observed a decrease in nocturnal cough with a salbutamol-dextromethorphan combo but not with dextromethorphan alone, according to the researchers. Regarding anticholinergics, Smith and Felman said that one randomized study on ipratropium bromide nasal spray found that it "reduced nasal discharge and sneezing in the first three days of a cold, but for some, resulted in a dry, uncomfortable throat for the latter three days of the illness." Atropine nasal spray also produced nasal drying in experimentally induced colds, although higher doses of the ingredient were associated with some adverse events, according to Smith and Felman. Only one expectorant study was evaluated: guaifenesin was found not to reduce cough frequency. No antitussive studies met the researchers' criteria for review because many were performed on animals or on humans with an "artificial cough." Smith and Felman concluded that, although "two-thirds of families possess between four and eight different types" of OTC drugs, "the scientific proof for their effectiveness is lacking in the medical literature." They speculated that the lack of good data "may be due in part to the difficulty of designing a methodologically precise trial for the treatment of the common cold." Smith and Felman also conceded that there may have been limitations in their literature review, including the "bias inherent in any database review" and that reviewers were not blinded to the source or results of the study. They also pointed to some "associated problems" with OTCs as "unintentional ingestions in preschool children" because the medications are "attractive to young children in terms of taste and colorful product packaging and rarely have safety caps." General side effects from use of OTC cold medications "should also be noted," Smith and Felman said, as should OTC drug prices. "The cost of buying these medications is not insubstantial and needs to be carefully weighed against any potential effectiveness," Smith and Felman said. In a statement on the JAMA study, the Nonprescription Drug Manufacturers Association asserted that Smith and Felman "failed to consider substantial unpublished data supporting the effectiveness of nonprescription medicines to relieve common cold symptoms in preschool children." As a result, NDMA said, "the study is incomplete, misleading and inherently flawed." NDMA pointed out that a special panel on pediatric dosing created by FDA "with access to all data, concluded that nonprescription medicines are indeed safe and effective cold treatments for young children." NDMA also observed that the two Canadian researchers "did not question the safety of nonprescription medicines." Smith and Felman acknowledge in the article that "some manufacturers state that other sources of drug evaluation," such as company trials, "should be included." However, they maintained that "the majority of the scientifically valid trials on the efficacy of these medications would be published and available to practicing clinicians in the existing medical literature."