Ask the doctor.  I want to donate blood, but I faint or come close to it nearly every time I have blood drawn at the doctor's office.  Can I do anything to keep myself from fainting?
Lee
Thomas
T
D001782:Blood Donors; D006801:Humans; D012307:Risk Factors; D013575:Syncope / Q000503:physiopathology / Q000517:prevention & control*; D019462:Syncope, Vasovagal / Q000503:physiopathology / Q000517:prevention & control*