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

A variety of therapeutic agents or chemical substances can induce either a transient or a sustained increase in blood pressure. These agents increase arterial pressure by either causing sodium retention and extracellular volume expansion or directly or indirectly activating the sympathetic nervous system. Some agents act directly on arteriolar smooth muscle. For certain agents, the mechanism of pressure elevation is mixed or unknown. Paradoxically, some agents that are used to lower arterial pressure may acutely increase arterial pressure. Also, a rebound increase in pressure may be encountered after discontinuation of certain antihypertensive agents. In general, these chemically induced increases in arterial pressure are small and transient; however, severe hypertension involving encephalopathy, stroke, and irreversible renal failure has been reported. Careful evaluation of a patient's drug regimen may identify chemically induced hypertension and prevent the need for evaluation and therapy. This study reviews the therapeutic agents or chemical substances that elevate blood pressure and their mechanisms of action.