My mother in law recently started taking fenofibrate and began experiencing chest pains and joint pain. She called her doctor today and they told her to stop taking the medicine, so her last dose was last night.
How long does the fenofibrate typically remain in a patient’s system? We’re leaning towards a visit towards urgent care just to be safe but her doctor seemed wholly unconcerned and I’m not sure if that’s due to experience or apathy 
I would not attribute chest pain to fenofibrate use unless/until cardiac chest pain has been considered and ruled out.
In other words, an urgent visit to an ER would not be a bad idea if she is having discomfort at present.
And yes, I am a doctor. Who prescribes fenofibrate and treats chest pain.
I am a patient who has been taking fenofibrate for years. I have not experienced and never heard of chest pain as a side effect. Sounds like something else is going on-a visit to an ER is called for.
I am late to this but it won’t stop me from adding my two cents.
First, almost by definition, anyone who is taking fenofibrate is at relatively high risk for coronary artery disease, i.e. at risk for having angina chest pain (pain due to inadequate blood supply to the heart itself) or even a heart attack. I say this because fenofibrate is used to treat high blood fat levels, a state considered to be a risk factor for coronary artery disease. In other words, chest pain in someone taking fenofibrate could well be due to angina and have no direct relation to drug itself.
Second, and speaking as someone who has a fair bit of experience with fenofibrate, chest pain is definitely not one of its recognized side effects. In fact, the best I can do in terms of connecting the pain with using fenofibrate is to speculate that IF the person is also using a statin drug (a not infrequently used combination since each of the two drugs has distinct and complentary salutory effects on blood fats, and many patients have a combination of blood fat abnormalites where the use of only one drug would leave some of the blood fat abnormalities unaddressed), then, since the combined use of fenofibrate and statins may carry a risk of developing muscle damage*, and since there are lots of muscles in the chest, and since this type of muscle damage is painful, then chest pain (due to chest muscle damage) can result.
*this interaction is much less common with fenofibrate than it is with its predecessor, gemfibrozil (Lopid).
Having said all that, the combination of chest pain and joint pains (if there even is a unifying diagnosis) could be explained by a number of (usually self-limited) viral illnesses.