The Food and Drug Administration is preparing to ban phenylpropanolamine, or PPA, which is found in products from Dexatrim to Triaminic. But legal steps needed for a ban will take a few months.
CBS News Medical Correspondent Elizabeth Kaledin reports the FDA asked manufacturers Monday to voluntarily stop selling PPA-containing drugs immediately and replace the ingredient with a safer alternative.
For consumers, the FDA's unusually strong health warning says: "We suggest you stop taking the drug immediately and use an alternative."
Rite Aid, with 3,800 drug stores in 30 states and the District of Columbia, soon will begin posting warning signs and removing products with PPA, spokeswoman Jody Cook said.
"We would advise our customers to check with the pharmacist about the alternatives," she said.
CVS Pharmacy, which has 4,100 stores, and Walgreen Co., with 3,200 stores, made similar announcements.
Consumers should look for PPA on the ingredient list of all nonprescription cold relievers, brand names and generic or store brands, and choose decongestant pills containing the safe alternative pseudoephedrine or use nasal sprays instead, said FDA nonprescription drugs chief Dr. Charles Ganley.
There are no over-the-counter alternatives for diet pills, however, so dieters will have to consult a doctor about prescription-only alternatives, Ganley said.
Whitehall-Robins Healthcare quit shipping PPA-containing Dimetapp on Monday. New liquid Dimetapp formulas lacking PPA will head for store shelves next week, with pill versions to follow. Also, some stores are selling PPA-containing versions of its Robitussin-CF product, and some are selling a new non-PPA formula, in boxes flagged with a yellow band.
SmithKline Beecham Consumer Healthcare said people should not use its PPA-containing Contac 12-hour Cold Capsules, but five other Contac versions contain the safe pseudoephedrine.
Top-selling manufacturers that refused to reveal their plans include Novartis Corp., maker of PPA-containing Triaminic and Tavist-D; Bayer Corp., maker of Alka-Seltzer Plus cold medicines; and Chattem Inc., maker of Dexatrim diet pills.
"It's safe to say that companies have been moving away from PPA use as a primary active ingredient for nasal decongestants," said drug industry analyst Mara Goldstein of CIBC World Markets.
About 6 billion doses of PPA are sold in this country each year, the vast majority without a prescription. However, there are a few PPA-containing prescription decongestants, and the FDA asked their makers also to stop selling them while it moves to ban prescription use as well.
The risk of a hemorrhagic stroke, or bleeding in the brain, is very small to an individual user.
"Not to be alarmist, it's clear this is a very rare event," Ganley said. "But even though it's rare, it's an irreversible event."
These are often deadly strokes, and survivors can be left disabled. With millions of Americans swallowing PPA daily, the FDA estimated it could be to blame for 200 to 500 strokes just in people under age 50.
"Whether it be 200 cases a year or 500, I think you can't lose sight of the individuals affected by this," said Ganley.
Hemorrhagic strokes typically occur in the elderly, and are extremely rare under age 50. Yet the first warning sign about PPA came in the 1980s, when medical journals cited several dozen young women who suddenly had strokes days after taking their first diet pill.
The FDA's records show 44 cases of hemorrhagic stroke among PPA users in the past 30 years. Most were women; the median age was 35, including a few who died while using diet pills even though medical records showed they weren't fat.
But the drug industry called the concern overblown and successfully argued more research was needed. So the industry's Consumer Healthcare Products Association funded a five-year Yale University study comparing PPA use among stroke survivors with healthy people.
The study's conclusion: PPA increases stroke risk for young women within three days of taking PPA-containing appetite suppressants, or within three days of taking their first-ever PPA dose for any reason. In some cases, using PPA increased stroke risk 12- to 15-fold.
Nobody knows why, although first-time PPA use sometimes temporarily raises blood pressure, an effect that wanes as the body gets used to the drug. Risk was highest with the higher doses -- more than 75 milligrams daily -- that dieters typically used.
Representatives of the over-the-counter drug market will comply, but noconcede that PPA is harmful.
"Even as our members are standing by the safety of their products, they acknowledge FDA's action and decision to move forward with new regulations," said William Soller of the Consumer Healthcare Products Association.
The study didn't find men at risk, but the FDA cautioned that enough men weren't studied to be sure they're OK.