What Are The Side Effects Of Placing A Heart Stent?

My mother had a heart stent placed in september and is on the usual plavix regimen. However, I am concerned that she may be suffering now from serious side effects of fatigue, lightheadedness, and dizziness. Her BP dropped so low that they have now taken her off the BP med, but her symptoms have not subsided. She is 82 but was very active (regularly walked the treadmill), high energy level, mentally sharp, etc. She is still great mentally but feels the need to constantly sit down, lean on something for support. Is there any way of determining if the Plavix is the problem? She's now being sent to a neurologist, but it seems to me that these symptoms became dramatically worse after she went on Plavix. Are there Plavix alternatives for the year she needs to be on it post-stent?