Hi, I have reactive hypoglycemia. I have strong side effects when I occasionally have to take a prescription med. For example, I took Zyrtec and Antivert per the NP and had an extreme reaction this morning. My breathing was slow and labored and yet I was having anxiety symptoms at the same time. I do not have a sugar reading, but it should have been low. These are not the only medicines I have had this kind of reaction too. Also, painkiller after minor back surgery. I cut the Antivert in half and still had this kind of reaction. I am female, 44, 155 lbs, 6 1 .