strep throat
"After taking one 500 mg. clarithromycin in about three hours became dizzy, uncomfortable in the head and short of breath.  Am afraid to take another although it was prescribed one every 12 hours. Have spent most of the day with head reclined and eyes closed.  Had same reaction to 500 mg.. of Azithromycin but could take 250 mg. with no problem.  Shall I ask the doctor to prescribe a smaller dose.  Am very fearful of another like this."