Hi Hilary,
Ok, Byetta lists a whole bunch of side effects. We all know the major most common side effect is nausea. The other side effects listed are that jittery feeling you had, dizziness, headache and acid stomach. Typically the dizziness and the jittery feeling is most often caused by hypoglycemia, which the manufacturer warns us about in no uncertain terms. Sometimes it is caused as I mentioned by such a sudden and percipetious drop in blood sugar that it simulates the symptoms of hypoglycemia. Now, with the dizziness lasting most of the day, that could be low blood sugar or it might be a specific reaction to the drug, as this drug puts your body through some awesome changes in a very short period of time. If you consider how really tiny a 10mcg dose is, its so little you can't even get it in a regular insulin syringe yet it does all these things within a few minutes to your body (literally 10-15 mins). Thats pretty powerful. So its not out of the question that as its working on your endocrine system, that there is some vaso activity happening that causes your dizziness and possibly a subsequent headache.
The upshot of all this is, you have to test your blood sugar when any of this happens to see where you are. Your body is telling you something out of the ordinary is happening and you have to take that clue and find out whether its something to be concerned about or something to ignore and let it pass.
Last night I went out to dinner, had a steak sandwich with fries, a forkfull of awesome chocolate cake, a couple of hours later, a few sugar free cookies and a handfull of cashews. I took a full dose of the oral meds with my byetta shot cause of all the extra carbs I was eating vs the half dose I normally take. (ate lottsa french fries and pure sugar with the cake). Well, that was a mistake, two hours later I was jittery and shaking and feeling dizzy. I did a finger stick and my BS was 50. Well, I definately learned a lesson on the oral meds, but the point here is that you have to do the finger stick to see what those feelings are telling you. Come'on, its just a tiny finger stick and it doesn't really hurt, just do it!!
Warren