The article discusses the FDA Advisory Council's unanimous decision that oral phenylephrine, commonly found in cold and flu medications, is no more effective than a placebo for congestion relief, potentially leading to its removal from over-the-counter drugs.

An FDA advisory council claims that the popular decongestant phenylephrine, which is included in many cold and flu medications, is no more effective than a placebo when taken orally. The 16-member FDA advisory council unanimously decided that oral phenylephrine, a typical active component in cold treatments, is not any more effective at alleviating congestion than a placebo. The panel's decision sets up a future FDA action that might result in the component being removed from several over-the-counter drugs.

Several previous studies that supported the drug's efficacy were disregarded by the panel due to difficulties with data integrity, small sample numbers, methodological flaws, and other factors. Phenylephrine "was not significantly different from placebo" in the recommended dosage according to more recent data from studies, according to the panel, including trials from 2007 that the FDA had examined when considering the drug after being prompted to do so by a citizen petition.

The primary reason the medicine should be taken off the market, according to the panel, is because of its poor bioavailability, which refers to the characteristics that enable the drug to be absorbed by the human body. However, the majority of FDA experts believed that considering a higher dose of phenylephrine was unnecessary or even harmful.

Why is phenylephrine given orally so ineffective?

It undergoes significant metabolisation, which begins in the gut wall. In the literature, a bioavailability value of 38% has been reported; however, this seems to be an overly optimistic estimate, since studies have also shown bioavailabilities of 1% or below.

Overall, the Cmax varies greatly from patient to patient, and the absence of cardiovascular side effects at low dosages supports the hypothesis that extremely low systemic effects (and anticipated poor decongestant effectiveness) are present. Apparently saturating some of the metabolic pathways causes the bioavailability to rise at greater dosages, but at the standard decongestant dose of 10 mg, forget it.

Phenylephrine's backstory

In order to reduce the abuse of pseudoephedrine as a component in the production of methamphetamine, it was relocated behind the pharmacy counter in 2006. Phenylephrine quickly gained favour as a substitute in the early 2000s.

The FDA experts presented the findings of five investigations on the efficiency of oral phenylephrine that were carried out during the previous 20 years during the two-day conference. The decongestant was shown to be no more effective than a placebo in every study.

They also reexamined the preliminary results that had been used to justify its OTC usage. The FDA discovered that the findings were inconclusive, did not adhere to current guidelines for research design, and may have had problems with data integrity.

"To sum up, we do think that the initial studies were methodologically flawed and did not meet the bar set by the current standard. The FDA expert who oversaw the evaluation of phenylephrine, Dr. Peter Starke, said: "In contrast, we feel the new data are reliable and do not offer evidence that oral phenylephrine is efficacious as a nasal decongestant."

Beyond its lack of efficacy, phenylephrine may also cause adverse symptoms including headaches, sleeplessness, and jitteriness. It may raise blood pressure at larger dosages.

The nasal spray phenylephrine, which is still believed to temporarily relieve congestion, is still deemed to be beneficial, according to the panel.

Alternatives

Phenylephrine and pseudoephedrine are the two most common oral decongestants in items that are sold in stores. Phenylephrine, which constricts blood vessels in the nasal passages, has long been regarded as safe and effective under obsolete agency criteria, and the FDA currently maintains this position. The component is still regarded as useful when used in nasal sprays, surgery, or eye-dilating procedures. Oxymetazoline, another component in nasal sprays, is also useful for congested noses.

Other medications to relieve congestion from the common cold include those containing oral pseudoephedrine, as well as nasal steroids, such as Flonase, nasal antihistamines, and oral pseudoephedrine for hay fever or allergic rhinitis. The chemical is absent from several well-known cold and flu remedies that don't explicitly address congestion. The market for manufacturers of cold medications might be severely disrupted if the agency thinks the decongestant should be removed from goods and they do not have enough time to replace it in popular products.

Additionally, since it was often used in illegal meth laboratories, sales of the substitute pseudoephedrine are regulated and are kept in locked cabinets or behind shop counters. Pseudoephedrine has additional adverse effects that might cause jitters, alertness, and blood pressure to rise. The FDA has been mulling over this problem for decades.

In conclusion, credible studies have shown the truth regarding phenylephrine.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Monish Raut is a practising super specialist from New Delhi.