In the last several decades, prescription drugs have flooded the market for a number of different ailments. Some of these drugs have greatly improved the life of the consumer. While their benefits are undeniable, there is a dark side to prescription drugs. If improperly used, these drugs can pose a great danger to its end user.
This is one of the reasons that drug companies are obligated to warn their consumers of the inherent danger of mis-use. It's because of the catastrophic injury the drug could cause if the drugs isn't taken properly or is taken by the wrong party, like a minor. If a failure to warn is not properly displayed, and it causes injury, this is a marketing defect and could be susceptible to a products liability claim.
The reason that most drug companies are obligated to present warnings on their products are as follows. The product presents a danger that the manufacturer knows about and the product is dangerous even when used in a reasonable manner. Also, that danger is not obvious to a reasonable. The term 'reasonable' here is a general term that encompasses the average consenting adult and gives some margin for who and what is considered reasonable.
Believe it or not, the term 'reasonable', can have a huge impact on how a marking defect product liability case is viewed by the court. That word allows for interpretation of the situation in context of the situation and legal doctrine. The bottom line is, drug companies are obligated to warn users of the potential danger attached to their product. If they did not properly warn and it caused injury, there could be damages sought by the injured.
Source: injury.findlaw.com, "Defects in Warnings," Accessed September 5, 2016