Every so often, the drug that scientists are certain will serve one purpose in fact serves a completely different one. Take scientists for Pfizer’s research center who developed an angina treatment that they gave to their subjects, who had very little of the response the scientists originally had thought, but. . .the male volunteers came down with prolonged erections. Adapting the medication a little, the scientists developed the blockbuster Viagra, as their medicine treated an illness by surprise.
Some of the drugs failed to help their first targeted disease but were successful in the second. Others actually harmed patients at first and then were rehabilitated for a new use. Still others are found to have 2 or more sucessful but widely differing usages.
Given the cost of bringing a drug to market, there is great value in finding that medicine already approved for one illness will in fact also treat other diseases. Finding another use could cut patient drug costs and also speed up how quickly new meds become available.
Just in the past few months researchers have discovered that Pfizer’s Celebrex, used to treat pain and arthritis, may actually help difficult-to-treat cancers. (You win some; you lose some, Pfizer’s records shows so far.) This drug got a bad rap (and Pfizer a gigantic fine) for aggravating heart disease and looked like its days were numbered. It was too good to trash, however, and new research saved its life. It is on the treatment dock for rare colon, bone and skin cancers.
An even more drastic change from harm to help was the now-infamous thalidomide. Introduced in West Germany in the late 50s to treat nausea associated with pregnancy, by 1958 it was on the market for treatment of morning sickness in over 40 countries. Unfortunately, thalidomide caused severe birth defects (horrific ones like missing limbs) among the children of the women who took the drug. Worldwide there were 8000-10,000 children born with birth defects related to thalidomide–and it was taken off the market in 1961-1962.
But thalidomide was not done, and it had great usefulness left. After some placebo-controlled trials it was approved in 1997 by the FDA as treatment for a complication of leprosy. In life number 3, it was shown to have a major anti-inflammatory effect in treating rheumatoid arthritis and other autoimmune diseases. And in yet a 4th incarnation, in the 90s it was discovered to be effective in treating the severe weight loss that occurs in patients with leprosy, AIDS, and tuberculosis.
That’s not the end of the story. Thalidomide is currently being used to treat cancer–the properties that causes the birth defects are what help stop the cancer’s growth. Thalidomide blocks blood vessels and limits blood flow, which can stop the growth of blood vessels that feed cancerous tumors. That’s 5–so far.
Of course, it is imperative that women who are taking thalidomide for another illness are closely monitored to make sure they don’t become pregnant.
While thalidomide was still being used for pregnant women, ketamine made its appearance. In 1962, ketamine was invented for use as an anesthetic on humans and animals, but by the 70s patients were reporting unexpected visions (hallucinations), which encouraged its use as a recreational drug during the 90s, and it even earned itself the dubious distinction of being a date-rape drug. Extensive use can yield both paranoia and egocentrism as side effects, and the drug can be both physically and psychologically addicting, although it is still used as an anesthetic.
But it’s been discovered to have another use, as well. Mice who took ketamine were less depressed one-half hour after the shot (how in the world researchers have learned to tell if a mouse is depressed is another story). Even better, it’s effective in humans, as well. Apparently ketamine kicks off a biochemical change that yields production of a protein called BDNF, which is linked to depression. Scientists don’t know how it works yet, but it seems to be consistently effective. A study author, Ronald Durman, a professor of psychiatry, says “The rapid therapeutic response of ketamine in treatment-resistant patients is the biggest breakthrough in depression research in half a century.”
Granted one probably never hoped to run home and tell one’s friends she was being treated with a veterinary drug–or, better yet, a date-rape drug–but the truly depressed person could, I’m sure, get over the moment’s awkwardness. (And if that particular use of something kind of kooky to treat depression interests you, stay tuned, so to speak; we have a post coming with some more treatments for bipolar and major depression that you just might never have thought would wind up in the mental health arsenal.) Before that we’ll have a few more examples of ways physicians came to treat an old illness by surprising new means.