I know I am caffeine sensitive. I have had issues with xylocaine in the past which my new dentist says relates to rate of takeup etc not allergy. I believe he is correct about that. But my issue is a sudden rise in bp, shakiness, nausea. Doesn't last too long but it happens sometimes. It's not as has been suggested by some doctors an emotional reaction. I have had it in very minor surgeries and had no issues with major gory things. It's sporadic too, so I think the takeup explanation of my new dentist is correct. Here's my question. If I am caffeine sensitive, which I am, then is it likely that the blood vessel constricting effect of xylocaine will affect my ear? Anyone here had any recent experience with relatively large amounts (teeth pulled etc)?