Drug-induced orthostatic hypotension.

Drug-induced orthostatic hypotension is an important clinical problem. When symptomatic, it is poorly tolerated by the patient, and can be a cause for discontinuing treatment. It may have more serious consequences if it leads to syncope, falls and injury, or to sustained loss of perfusion of vital organs resulting in heart attack or stroke. Orthostatic hypotension is easily detected by procedures available to all physicians, who should maintain a high index of suspicion when prescribing drugs commonly known to cause this condition, especially in the elderly. Since the medical conditions calling for the use of these drugs are extremely prevalent, the screening and monitoring of orthostatic hypotension should be instituted as a routine precaution in appropriate patients. Hypertension affects two-thirds of elderly patients. Orthostatic hypotension is an infrequent adverse effect of most of the drugs in current use in the treatment of hypertension; it is, however, more common with alpha 1-blockers (first dose), adrenergic blockers and centrally acting drugs. Sudden loss of blood volume, or excess diuresis, may precipitate orthostatic hypotension in any hypertensive patient. Drugs used for the treatment of psychiatric illnesses are all associated with a significant incidence of orthostatic hypotension: phenothiazines, tricyclic antidepressants and monoamine oxidase inhibitors. Cardiovascular drugs associated with hypotension include dopamine agonists, antianginals and antiarrhythmics.