Drugs & MedicationsEye, Ear, Nose. ThroatInfectious DiseasesRespiratory


Millions, if not billions, of dollars are spent on cold and allergy medications that may not actually work. Yes, that Triaminic, Dristan, Coricidin, or Vicks that you have relied on for years may not actually be worth the money you spent on them! The “effective” ingredient in most OTC cold medicines is the decongestant, phenylephrine. It comes in an oral tablet form or as a nasal mist. 

A decongestant is a drug that reduces the swelling in the nasal airway caused by the cold virus. When a virus invades the lining of the nose, nasal blood vessels dilate, the nasal membranes become inflamed and swell, and mucus leaks from the surface layer cells. Thus your nose feels stopped up and runs a lot. There is, then, an increase in the measurable nasal airway resistance (NAR)—the patient has a hard time getting air through his swollen nose forcing him to breathe through his mouth. The purpose of phenylephrine is to prevent nasal swelling and reduce nasal airway resistance (NAR). But does it do what they claim?

Multiple scientific studies have addressed that concern. A review of 8 separate studies compared the effects of 10 mg of phenylephrine and 25 mg of phenylephrine to placebo. They discovered that 10mg caused only a 10.1% improvement, and 25mg a 27.6% improvement in NAR compared to placebo. They concluded that there is insufficient evidence that oral phenylephrine is effective for OTC use as a decongestant. 

Another study by Castillo, et al. also showed that oral phenylephrine “did not offer substantial relief from nasal congestion compared to a placebo in adults.” The “prevailing conclusion was that phenylephrine’s efficacy was limited.” Consistently, the findings showed “phenylephrine was not more effective than placebo” in relieving nasal congestion. It was, however, safe with “no life-threatening adverse events.” Doctors, then, should “explore alternative treatment options.” 

Desjardin and Berlin, on the other hand, found that doses of phenylephrine ranging from 5 to 25 mg showed a “significant reduction in NAR compared with placebo.” They agreed with the FDA’s position showing evidence of efficacy. Their review, based on 12 studies, showed 7 of them to support efficacy at a dose of 10mg. 

So, does phenylephrine work? There are data to support both efficacy and inefficacy. Only the patient who takes it and feels better really knows! 

References: Hatton RC, Winterstein AG, McKelvey RP, Shuster J, Hendeles L. Efficacy and safety of oral phenylephrine: systematic review and meta-analysis. Ann Pharmacotherapy 2007 Mar;41(3):381-390.

Castillo JL, et al. The Use and Efficacy of Oral Phenylephrine Versus Placebo Treating Nasal Congestion Over the Years on Adults: A Systematic Review Cureus 2019 Nov 19;15(11):?

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