I am in the second week of having allergy shots. The office did not advise me that I should take antihestamine prior to having my shot, but I took zyrte-d 30 min before. I had my injection at 11am. In the afternoon around 5pm my heart was racing. It went up to 104 bum. Could this be the result of taking Zyrtec-d instead of just taken Zyrtec without the D, or can that be just a reaction to allergy shots?