Why are "older" drugs that have been on the market preferable from a safety perspective than "newer" drugs just licensed?
In recent years, the FDA has been pressured to allow "expedited approval" for drugs to get them to market. While "safe", many of these drugs had some concerns which prompted the FDA to require that the drug manufacturer fund and undertake studies AFTER the drug was on the market to assess safety. The FDA required that 1,200 "post-marketing" studies be performed in recent years.
However, only 1/3 of the studies mandated by the FDA for these newly-licensed drugs have even been initiated - yet the drugs in many cases are not only on the market but being actively marketed.
So if you're physician wants you to try an "old standby" that she's comfortable with - go with her advice. The "new, new thing" you may have seen on television or which she may be providing as a 'free sample' may not be the proven, safest alternative over time.
Have a healthy day.
Dr. Mike