High blood pressure. A side effect of drugs, poisons, and food.

Arterial hypertension, either transient or persistent, may be induced or aggravated by ingestion of various chemical agents, such as drugs, poisons, and food. Most of these agents either cause sodium retention and expand extracellular fluid volume or act as direct or indirect sympathomimetics. Others act directly on arteriolar smooth muscle. For a few agents, no precise mechanism has been ascertained. Hypertensive reactions may also occur as a result of drug interactions or food and drug interactions. In addition, paradoxical increases in pressure may be encountered during or after discontinuance of antihypertensive therapy. In general, these pressure increases are small and transient; however, a few have been associated with severe hypertension involving encephalopathy, strokes, and irreversible renal failure. Careful review of a patient's drug regimen, including over-the-counter preparations, may avoid chemically induced hypertension. Identification of any offending or incriminating agent will prevent the labeling of a chronic illness and obviate the need for lifelong antihypertensive therapy.