The Science of Naming Drugs (Sorry, 'Z' Is Already Taken)

Not only is the process of christening a new product a lot trickier than it sounds, the most obvious candidates can be the most perilous.

When British drug regulators told doctors recently to stop writing prescriptions for six antidepressants for children under 18, the drugs in question sounded like a "Star Wars" cast list: Paxil, Effexor, Celexa, Lexapro, Luvox and Zoloft. (A seventh, Prozac, was approved.)

It has often been noted that drug makers have favorite letters, and that they run the gamut from X to Z. Think Nexium, Clarinex, Celebrex, Xanax, Zyban and Zithromax. But why are these letters so popular?

"Some letters look better in print, make sounds people like saying and are associated with innovation," said Steve Manning, the managing director of Igor, a San Francisco branding company. "X is associated with science fiction, high tech, computers, automobiles and drugs." As in "The X Files" and "The Matrix," Xerox, the Lexus and theMicrosoft X-box.

James L. Dettore, president of the Brand Institute, a branding company based in Miami that has tested 8,400 drug names in the last seven years (its successes include Lipitor, Clarinex, Sarafem and Allegra), said the letters X, Z, C and D, according to what he called "phonologics," subliminally indicate that a drug is powerful. "The harder the tonality of the name, the more efficacious the product in the mind of the physician and the end user," he said.

If only it were that simple. In the neon wilderness of branding, where almost everyone thinks Nike began life as a sneaker instead of a goddess and almost nobody knows that Altria is a tobacco company, a drug is probably the hardest thing to name.

Executives want something that will entice billions of dollars in sales. Customers want a hint of what it does. The Food and Drug Administration doesn't want implied medical claims. And if it sounds too much like another drug, a pharmacist might accidentally kill the customer.

Mr. Dettore says he tests up to 15 names for each client's drug. First he checks data banks in about 40 countries to see whether the names are already copyrighted and to make sure they don't mean anything misleading or vulgar in other languages.

He has focus groups talk about their feelings. For example, Sarafem - a form of Prozac aimed at women with severe premenstrual irritability - comes from angelic seraphim, "but with -fem from feminine and a very soothing prefix," he said.

"Lipitor is 'lipid regulator' with the -tor of atorvastatin, the generic name," Mr. Dettore added, with the plus that "-or is grounded as a cardiovascular-sounding suffix." Levitra, the Viagra competitor, comes from "elevate," he said, but "we tested and it sounds European, elegant, with premium connotations." "Le'' indicates masculinity in French, he noted, and 'vitra'' can allude to vitality. (Viagra is also said to make men feel vital - and like mighty Niagara Falls.)

Mr. Dettore then recruits a test panel of doctors to scribble and phone prescriptions to a panel of pharmacists to see if confusion ensues. Finally, he submits the best two names to the F.D.A.

The agency rejects about a third of all applications, weeding out dangerous sound-alikes. It frowns on syllables like "ultra," "max" or "new." (Of the 1,035 drugs approved by the F.D.A. from 1989 to 2000, about 700 were "me-too" drugs with virtually the same ingredients as previously approved ones.) The same goes for names that sound like generic drugs. Prozac and Paxil, for example, are fluoxetine and paroxetine, and so "-oxetine" endings are forbidden because they will eventually compete with the generics.

The agency also turns down faddish suffixes: does "SR" mean "sustained release" or "senior"? Does "XL" imply "extra long" or "excellent"?

"The original name proposed for Rogaine was Regain, as in you regain your hair," said Bill Trombetta, a professor of pharmaceutical marketing at St. Joseph's University in Philadelphia. "But the F.D.A. said 'You can't use that name - it promises too much.' "

Mr. Manning of Igor sounded cynical about phonologics. "Do I think Zoloft could have been Claritin and vice versa?" he said. "Absolutely. I mean, who cares?"

Drug companies clearly do, and can easily spend $500,000 on a name and packaging. But after clinical trials costing tens or hundreds of millions of dollars, "even a couple of million dollars spent on a name it can't use, that's chump change," Professor Trombetta said.

The companies even register names before they have a drug to fit them. "There are about 12,000 drugs out there, and only so many Z's and X's to go around," Professor Trombetta said. "The brand is thought up when it's in the petri dish."

Dr. Yusuf K. Hamied, chairman of Cipla, an Indian drug company that copies many drugs patented in the West and makes AIDS drugs for Africa, operates in a less restricted environment. He can let his imagination roam.

He makes knockoffs of Viagra, Levitra and the newest member of the class, Cialis. He originally planned to market Cialis in India as Lexis or Elexis, playing on Lexus. But since it's known in Europe as "the weekender" because its effects last 36 hours, he's now thinking of "Y-End?" "It's a gimmick," he said. "It may catch on."

In India, his version of Viagra is called Silagra, from its generic name, sildenafil citrate. Indians were already so familiar with Viagra that it made sense to echo Pfizer's name, he said. But in Latin America, he sells it as Eviva. It sounds like "revive," but also has an echo of the female Eve. He said he almost named it Tarzia "because it makes you feel like Tarzan." In the Middle East, he forgoes all subtlety. There, it's Erecto.