Clarithromycin
"I didn't experience or notice any of the side effects until I started having the metal taste.  This started happening on day 7.  After reading all the side effects I realized that I did suffer from the excess heart rate, nightmares, lethargic, wanting to sleep all the time and of course the metal taste....I could only think it's similar to keeping a large amount of dirty pennies in your mouth for several hours.  I only get the taste towards the evening and all night."