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The common cold is aptly named, with an estimated 500 million infections annually in the United States. Adults in the U.S. average two to three colds per year, and preschool children five to seven. Colds create a huge economic burden from missed work days, health care visits and medications, an estimated $17 billion directly and $22.5 billion indirectly per year.
The most bothersome cold symptom for many adults is cough, which can persist for days, weeks or even months after other cold symptoms subside.
One may have thought the massive innovative capacity of the U.S. medical care system and pharmaceutical industry would have extinguished cough due to the common cold -- or at least created a lucrative line of prescription drugs for it.
Not only has that not occurred, but in fact, according to an expert panel review in Chest, today there are exactly zero proven effective therapies for cough due to the common cold. Authors concluded that nothing has been shown to work well enough to make any evidence-based recommendations.
Rather than conclusive proof (evidence of absence), the real finding was a general absence of evidence for or against any treatment for cough due to the common cold, after hundreds of randomized trials and several systematic reviews. With few exceptions, these studies didn’t address cough specifically, or were of too low quality for strong conclusions.
Authors suggested adults and children not use over-the-counter cough and cold medicines (like decongestants or antihistamines) until and unless they are someday shown to help reduce cough. They suggested against use of NSAIDs for cold-induced cough, as well.
They considered endorsing zinc, but decided there wasn’t enough evidence.
For children, the experts suggested trying honey, and avoiding codeine.
Oral corticosteroids are frequently prescribed for persistent cough after the common cold, but in a randomized trial in JAMA, oral steroids did not improve cough due to colds. An observational study associated short-course corticosteroids with sepsis, deep venous thrombosis and fracture in the subsequent months, although confounding by indication was likely.
In a randomized trial in BMJ, broad spectrum antibiotics (Augmentin) didn't improve cough due to acute bronchitis (even when patients had the feared discolored sputum the lay public widely perceives as a criterion for needing antibiotics). NSAIDs (ibuprofen) were also tested in an arm of that trial: they didn't improve cough, either.
Cough is a notoriously difficult to eradicate symptom, whatever the cause. Cough may be present in up to 8% of visits to primary care physicians, and much higher in pulmonology visits. In the U.S., many of those patients expect to leave the doctor's office with a prescription, not reassurance and a tincture of time.
In the absence of evidence proving various cough remedies don't work, and with the ascendance of patient-satisfaction scores as drivers of physician behavior, most patients who request "something for the cough" will continue to be prescribed "something." Unfortunately for everyone involved, that something is usually antibiotics, corticosteroids, or both.