I'm of two minds with this issue. While many of the ads are insidious, some are useful. I break them down into two categories: ads for drugs to alleviate conditions a consumer can diagnose or notice themselves, and those that require expert medical opinions or tests to discover.

Example of former: Viagra
Example of latter: Lipitor

The reason I don't have a big problem with the former is that many people are aware of conditions, (ED, allergies, etc) but may not know that there are prescription medications to help. They may not have seen a doctor about the condition.

With the latter, conditions such as high cholesterol necessarily involve a trip to the doctor before you even know about it. So these ads just serve to get you to influence your doctor despite your being pretty ignorant on the options. I speak generally, of course. Researching your options is always a good thing and many people are fully capable of sorting through medical information and coming to an informed opinion. But that's not who the ads are targeting.