Is there a difference in the generic desmopressin and the brand name dDAVP?
I am not sure why you experience heavy pressures in your chest before and after your doses of dDAVP. If may be due to rapid shifts in body water, particularly if you are taking the drug in such a way as to allow the effects of one dose to wear off before taking the next dose. If so, you should talk with your doctor about the possibility of taking the dDAVP on a more regular schedule that prevents intermittent escape.