I would argue that it is some of each.
On the one hand, a great deal of study and testing is done before any medications are released to the public. I also know that some medications I've used have proven helpful, and I've seen medications do great things for others, dealing with a wide range of medical issues.
On the other, in the United States at least, it seems that the key motive behind almost anything is profit. In many cases, the most profitable thing is selected above the most effective or efficient.
It also depends on the person and the medicine. Most medicines have side effects, and many people have allergies or other characteristics that could cause them to respond in an unusual way to a given medication.
The moral of the story is, be careful with what you choose to put in your body, and educate yourself on the options.