Yes, prescription drug ads tell the complete truth about their products. It is my belief that prescription drug ads list all possible side effects to their drug and highlight the positive effects that will be beneficial to patients. The commercial presents the drug in a good light, but isn't untruthful.
There is absolutely no way that they tell us everything right in the commercial. If they were to tell you that Viagra was first tried on monkeys and hundreds of them died no one would buy it. If they read off all one hundred possible side-effects not a single bottle would be sold.
Although advertisements always make sure there's a list of potential side effects in the fine print or at the end of every televised ad, pharmaceutical companies are a profit driven industry who are not always motivated simply by helping out the people that these medicines are created for, and may hide certain facts about what they are peddling.
Prescription ads never tell the whole truth about their products. Their intent is to sell as much of their product as possible without the consumer knowing about the side effects. For example, a new prescription ad will go over the side effects quickly, so that people will not pay much attention to them. The whole point is for people to loose focus of the bad side effects and still buy the product advertised.