Resolving the phenolphthalein flap

Drug Store News, July 14, 1997 by Rob Eder

Manufacturers routinely go to great lengths to gain increased market share for their products. Detergent companies, for example, have routinely taken pot shots at Brand X. McDonald's and Burger King swap blows on a regular basis. Coke and Pepsi have taken turns trying to flatten each other's soda sales.

When a neutral third party steps in with the findings of an independent study, things can become a little more interesting as manufacturers apply their own spin to the results. Cancer studies on the effects of saccharine on lab rats created an inroad for the makers of Nutrasweet. Last year, Advil and Tylenol went toe to toe: Whitehall Robins, the makers of Advil, had Tylenol users wondering if their livers and kidneys could handle the mix of acetaminophen and alcohol, while J&J raised concern over the effects of ibuprofen on the stomach.

And now, laxative manufacturers are gearing up for what could be a long, drawn-out battle of attrition for market share. Novartis, maker of the longtime category killer Ex-Lax, is digging itself a trench in hopes it will be deep enough to endure the full frontal assault currently being launched by Schering-Plough, which is using the results of a recent National Toxicology Program study as ammunition.

However, this is just the most recent clash between the two OTC titans. By 1989, Ex-Lax, the most popular laxative since the discovery of the prune, had been finally unseated by Schering-Plough's Correctol as the category's top performer. Correctol owned the top spot until December 1995, when NTP released the results of a study examining the effects of phenolphthalein, the active ingredient in many common laxative products, including Ex-Lax, and, at the time, Correctol, as well.

The study determined that phenolphthalein caused cancerous tumors in lab rats and mice. Schering-Plough made the decision to reformulate Correctol, replacing phenolphthalein with bisacodyl as the product's active ingredient. Novartis seized the opportunity to regain the top share of the market by launching an ad campaign questioning the efficacy of Correctol's new formulation.

In the meantime, the NTP data were presented to the Food and Drug Administration's Cancer Assessment Committee, which concluded this past spring that the use of phenolphthalein presents a significant cancer risk to humans. The committee's findings led the FDA to announce that the agency would reclassify phenolphthalein from a Category I ingredient (safe and effective) to Category III (more data needed), although no time line has been set for the switch.

So, as the fate of phenolphthalein hangs in the balance, the principal players are assuming far different postures. Novartis is urging the FDA to conduct human epidemiology studies, citing their product's 100-year reputation of safety and efficacy. In addition, the company questions the reliability of the NTP data, claiming that the dosages administered to the lab rats were at least 30 times greater than the maximum recommended for human use. Meanwhile, Schering-Plough continues its repositioning of Correctol as the safe alternative to phenolphthalein-based laxatives.

While Novartis attempts to weather the storm and Schering-Plough seeks to ride the wave, another leading laxative manufacturer, Bayer, has decided to jump ship, announcing that it would not return its only phenolphthalein-based laxative, Phillips' Gel Caps, to the shelves. And, in actuality, none can expect smooth sailing ahead, as the FDA has called for further studies on stimulant laxatives with pharmacological traits and clinical uses similar to phenolphthalein, such as bisacodyl.

And so, as the FDA figures out a way to resolve the whole phenolphthalein flap, top-selling laxative makers are forced to sit back and see how it all turns out in the end. Still, one thing is worth considering, and it's been said before. Manufacturers of similar products all drink from the same well. That is, in using scare tactics to erode a competitor's share of the market, manufacturers cast a pall over the entire category. That kind of gives a whole new meaning to the term category killer. You see, the customer won't remember that a particular headache remedy, laxative or artificial sweetener might do them harm, they're far more inclined to simply steer clear of such products altogether.