It was at the end of a busy Monday when my ever-so-polite patient, just shy of 90, rang to inquire if it was a convenient time to talk. 

“Yes,” I assured her. 

“I’ve just managed to make it to the bed,” she told me. 

She announced that she was having a “funny turn”, and then proceeded to relay a rather confused story about having taken some magnesium for cramps recently, getting a huge bruise down one leg the day after starting the supplement, and wondering whether magnesium could interact with rivaroxaban.