Baby boomers who want to stay young forever--and who desires anything less these days?--are giving the pharmaceutical industry something that very few consumer-products makers have: a growing, demand-driven market. American companies will spend more than $20 billion this year to develop pills and potions for everything from wrinkles and baldness to the prevention of strokes and heart attacks. More boomer selfishness? Maybe not. If science insists on getting more mileage out of the engine and prolonging our lives--thus allowing us to work into our 70s--what's wrong with maintaining the chrome and fenders? "We expect medicine to deliver that," says Susan Coleman, president of NCI Consulting, a New Jersey adviser to drug companies.

The payoff can be awesome: 79 million boomers have begun to turn 50 at the rate of one every eight seconds or so. That's why this $300 billion industry is the most profitable segment of the FORTUNE 500. Pfizer's impotence pill, Viagra, already the hottest new drug launch ever, could reach $2 billion in sales by the year 2000. Delirious investors pushed Pfizer's stock from about $45 a share a year ago to $118.25 last week.

Although Viagra is a kind of lucky accident--its application to impotence was discovered in 1992 during research on heart medications--chairman William Steere realized the significance of such drugs in the marketplace. Says Steere: "It occurred to me at the time that with the aging baby boomers, quality of life is going to become very important." Indeed, Steere has practically repositioned the company to deliver better living through chemistry. Last year sales hit $12.5 billion, and profits reached $2.2 billion.

Today the industry as a whole is feverishly developing silver bullets for boomers that, like Viagra, seek to rewrite the physical and mental decline genetically programmed into each of us. Among the latest life-style-enhancing remedies:

LET THEM EAT CAKE Lipitor, a cholesterol fighter developed by Warner-Lambert and marketed with Pfizer, roared out of the chute last year, the only Rx rookie to rack up $1 billion in first-year sales. Lipitor lowers cholesterol--and by extension the risk of heart attacks--by interfering with an enzyme that the liver uses to make cholesterol. Analysts expect sales to top $3 billion by 2000.

GOOD HAIR DAYS With as many as 50% of the American men who are 50 or older scratching their heads over male-pattern baldness, Propecia, made by Merck (1997 sales: $23.6 billion), is the first pill that aims to grow back hair. The company says two-thirds of the men who took Propecia in clinical trials sprouted natural-looking hair. Sales of the drug, which Merck launched in January, could approach $750 million by 2000. One rare (less than 2%) side effect: depressed libido. Propecia and Viagra cocktails, anyone?

LOOK GOOD, FEEL GOOD Bristol-Myers Squibb is testing a remedy designed to fade skin blotches caused by exposure to the sun. The company is awaiting final approval from the FDA. Johnson & Johnson has clinical proof that a substance called Renova can reduce wrinkles. Renova is based on tretinoin, derived from vitamin A.

PLAY ALL DAY Monsanto's Celebra is a new-generation anti-inflammatory drug called a COX-2 (cyclo-oxygenase) inhibitor. It blocks arthritis pain without attacking the stomach lining, a major problem with anti-inflammatories. To be co-marketed by Pfizer in the U.S., Celebra could go on sale by 2000.

SLEEP ALL NIGHT The ability to sleep soundly decreases with age. Sonata, which American Home Product's pharmaceutical unit Wyeth-Ayerst hopes to launch next year, is designed to induce sleep without producing a groggy feeling the next morning. "There is a tremendous issue in sleep disturbance," says consultant Coleman. "So when we get a product that people have utter confidence in, that will be a gold mine for someone."

MEDICAL MIRACLE? Perhaps the most striking of all recent drug news were reports that Evista, Eli Lilly's new osteoporosis medicine, could also be effective in preventing heart disease and breast cancer in older women. Clinical trials of the drug's ability to stave off heart attacks begins in May, with testing of the impact on breast cancer to start later this year. The implications could be huge for Lilly. Carl Seiden, an analyst who follows the drug industry for J.P. Morgan Securities, says sales of Evista as an osteoporosis remedy alone could approach $2 billion by 2002.

COMFORT AND CONFIDENCE Incontinence affects an estimated 17 million Americans, but only some 20% seek help. Women are the most frequent sufferers because the condition is often linked to menopause. Pharmacia & Upjohn is rolling out a bladder-control drug called Detrol this spring. The pill is the first such medication to win federal approval in more than 20 years.

The drug companies aren't the only ones that will benefit from boomer products. The industry will spend more than $1 billion this year selling its new remedies. The pitches may have the familiar ring of youth-in-a-bottle advertising. Only this time, the stuff will really work.