In a move aimed at stamping out the escalating "backyard production" of the illegal street drug methamphetamine, or "crystal meth, the newly enacted Combat Methamphetamine Epidemic Act now restricts the sale of drugs that contain pseudoephedrine in the US.
Drug firms such as Pfizer and Johnson & Johnson replaced the pseudoephedrine in some of their products with phenylephrine in order to bypass the new law, which requires all products containing pseudoephedrine to be kept behind the counter.
However, phenylephrine doesn't last as long as pseudoephedrine and has not been used widely in these types of medications in the past because of its limited effectiveness.
It is for this very reason that some drug makers, such as Schering Plough decided not to reformulate its products. Others have decided to hedge their bets, reformulating some, while leaving certain products as they are.
Now industry watchdog and congressman Henry Waxman, among other pharma experts, have expressed concerns that those drugs that have been newly formulated are not working well enough for their intended purpose.
In a peer-reviewed letter to the editor published recently in the Journal of Allergy and Clinical Immunology, two University of Florida researchers concluded that there is "virtually no evidence to show that phenylephrine oral nasal decongestants at the FDA-sanctioned dose of 10mg are effective."
To address the issue, Waxman has twice called upon the US Food and Drug Administration (FDA) to launch an investigation into the use of phenylephrine in these drugs, with a review of all available evidence, with the latest call spurred on by the release of a new study by Schering-Plough.
According to the drug firm, phenylephrine was "not significantly different from placebo in decreasing nasal congestion" while pseudoephedrine was "significantly more effective," in a clinical trial involving 38 people.
"Medical studies indicate that phenylephrine may be no more effective than placebo in alleviating nasal congestion, raising questions regarding FDA's conclusion that the drug is safe and effective for over-the-counter use," said a statement on Waxman's website.
Despite Waxman's calls, the FDA has so far declined to undertake a review.
The FDA was asked by In-PharmaTechnologist to comment, however, declined, stating "any correspondence between Congress and FDA is usually not releasable by the agency."