Clarithromycin
"Doc put me on this drug as a "broad spectrum" for a suspected bacterial infection.  What started out ok (bad taste but no other side effects) turned into HELL.  On day six, this drugs side effects came on strong.  Horrible taste, AWFUL nightmares to the point where I would lay in the bath or repeatedly read a poster in my room to avoid falling asleep.  Stomach pain and nausea were unbearable and I was very disoriented."