Jessica developed atrial fibrillation which is a heart irregularity. Neither heart medicines nor shocking the heart could correct the rhythm. We did our sleuthing. I asked her to stop the Excedrin. She did and ten days later her heart returned to a normal rhythm.
Caffeine can overstimulate an excitable heart.
Annie read a popular book about the treatment of arthritis with low dose antibiotics. This was useful in those with postive blood tests for an organism called mycoplasma. After 5-6 doses she thought her arthritis was better. She didn't want to because she thought it was helping her. This looked like what is called drug fever to me.