“Two decades ago, it became clear that Congress was intent on trying to curtail illicit methamphetamine production by restricting access to pseudoephedrine, a meth precursor that was also widely used as a decongestant in cold and allergy remedies such as Sudafed. Pfizer, the manufacturer of Sudafed products, responded by announcing that it would start selling alternatives containing a different active ingredient: phenylephrine.”
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“The main problem with phenylephrine: When taken orally, it is so thoroughly metabolized in the gut that almost none of it ends up in the bloodstream. “The new data appear compelling that the monographed dosage of oral [phenylephrine] results in no meaningful systemic exposure or evidence of efficacy,” says an FDA briefing document that was presented to the advisory committee. “Furthermore, the review suggests that higher doses…have also not shown efficacy. These findings are supported by in vitro and in vivo clinical pharmacology data showing that orally administered phenylephrine undergoes high first-pass metabolism resulting in less than 1% bioavailability.”
Legal restrictions on pseudoephedrine sales, in short, gave us reformulated products, including pseudo-Sudafed, that not only do not work as well but apparently do not work at all”
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“Legal restrictions on pseudoephedrine, by contrast, took it off the shelves and put it behind the pharmacy counter, whence it can be retrieved only under certain conditions.”
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“Restrictions on pseudoephedrine did affect the illicit methamphetamine trade, primarily by shifting production from small-scale U.S. operations toward large-scale Mexican traffickers. But by no means did that crimp the supply.”