Hypotension:Anyblood pressurethat is below the normal expected for an individualina givenenvironment.Hypotensionis the opposite of hypertension (abnormally highbloodpressure).
Hypotensionis a relative term because the blood pressure normally varies greatly with activity, age, medications, and underlying medical conditions.
Low blood pressure can result from conditions of the nervous system, conditions that do not begin in the nervous system, and drugs.
Neurologic conditions that can lead tolow blood pressureinclude changing position from lying to morevertical(postural hypotension), stroke, shock, lightheadedness after urinating or defecating, Parkinson's disease,neuropathyand simply fright.
Nonneurologic conditions that can causelow blood pressureinclude bleeding, infections, dehydration, heart disease, adrenal insufficiency, pregnancy, prolonged bedrest,poisoning,toxic shocksyndrome, and blood transfusion reactions.
Hypotensivedrugs include blood pressure drugs,diuretics(water药丸),(特别是心脏药物calciumantagonists-nifedipine/Procardia, beta blockers-propranolol/Inderaland others),depressionmedications (such asamitriptyline/Elavil), andalcohol.
The word hypotension is ahybridof the Greek "hypo" meaning "under" and the Latin "tensio" meaning "to stretch." In French, "latension" is "the blood pressure."
