Given that most patients, (we all become patients eventually), are not medical professionals, allowing drug companies to saturate the airwaves with prescription drug commercials/advertisements serves only to get the public to pressure doctors into prescribing a particular drug which may or may not be appropriate. Doctors are well educated in what is best for their patients without additional undue pressure.
The banning of these commercials should have a positive financial impact for the drug manufactures; they can save on the massive spending toward these commercials and apply the savings to further research or reduce costs.