As someone who works in the industry, this shouldn't be much of a surprise. Most drugs have a very low incidence of serious side effects. Even over the counter products do. The reason they are approved is that they are so rare. A great example of a serious side effect is Toxic epidermal necrolysis (TEN) and Stevens–Johnson syndrome (SJS). There are many everyday drugs (ibuprofen, antibiotics, etc) that can cause this…
I had hives all over my body, plus muscle pains all over my arms and legs (at its worst, I could barely hold a razor and needed a cane in order to shuffle around). You know what comes up when you search for bumps all over your body combined with pain? Yeah, TEN.
Fortunately it was just allergy-induced hives and myalgia, and I understand that the pain I went through functioned like an acute case of rheumatoid arthritis, but that was still nasty. I ended up in the emergency room twice. The first course of steroids they prescribed me wasn't long enough or strong enough: the hives never fully went away, and the myalgia came back as soon as I finished the prednisone. So I had to go back, and then they gave me a shot of decadron and put me on a two-week course of prednisone.
Yeah, that wasn't pleasant. At all. The side effects I suffered from the prednisone were awful and insidious, but at least it killed the allergic reaction.
Oh, and during that time, a friend of mine died, and her death was all over the local news because of how mysterious it was (they still haven't solved it or even released a coroner's report yet). April 2017 was terrible all around.