Causes of low blood pressure vary. Medicines that are used in surgery such as anesthesia are known to cause low blood pressure. This also includes loss of blood during surgery or in an emergency. This can also lead to low blood pressure. Some high blood pressure treatments may also lead to low blood pressure as a side effect. Of particular note are diuretics. If these particular drugs are abused may lead to a drop in blood pressure to dangerously low levels.
Treatment of elevated systolic blood pressure has been known to cause a sharp drop in diastolic blood pressure readings especially in older people. This can be dangerously low to the loss of life in a patient. The falling in diastolic blood pressure is a direct result of an attempt to lower elevated systolic blood pressure. Other conditions and diseases that can cause a fall in blood pressure is diabetes and fainting and dehydration. Some women have low blood pressure in hot weather and when engaged in dieting.