I wasnt taking anything at all alex when I had that symptom. The symptom was too extreme for me to even remember to take anything and I wasnt even waking up long enough to thinking about taking pills and stuff (all my awake time was spent.. eatting, drinking and going to toilet (which i didnt often a all due to being dehydreated due to sleeping so much.. I was only going once a day or less. Its amazing my kidneys didnt stop working). I dont even think I was even washing myself during that time...not awake enough. I equate this symptom with being almost completely comatose. U hardly exist with it. I actually dont think this is a common ME/CFS symptom.. its different to just crashing and being bedridden with exhaustion ..even bedridden exhausted ME/CFS patients usually wake up at times. This symptom is life threatening... you could sleep throu world war three and the town being bombed and wouldnt know. (Others may not be able to wake u up at times when one has this.. you can be completely unresponsive to even being shaken). It's like narcolespy too at the short periods one is awake.