Merck is pulling a drug off the market after reports of nasty side effects including difficulty standing. But don't worry, it isn't hiding in your medicine cabinet. In fact, if you aren't a farmer, you've probably never heard of it since it isn't approved for human use.
It may surprise some investors that the animal health divisions of the major pharmas aren't primarily for treating your cuddly pet ailments -- they are geared toward livestock. Merck's drug that is under fire is a food additive called Zilmax used  to "improve production efficiencies in beef cattle." That translates into making them bigger, faster. Now Zilmax wasn't a blockbuster -- it did a little more than $150 million in sales -- so the impact to Merck shouldn't be too bad. It could provide a boost to Eli Lilly, which has a competing feed additive called Optaflexx, with no reports of any related health issues. 

In this video, health-care analyst David Williamson explains why this particular suspension shouldn't effect Merck too badly, but why investors should monitor the situation closely as public opinion could turn against these type of products.

Follow David on Twitter: @MotleyDavid.