Precautions in use of antihypertensive drugs, including chlorothiazide.

Abstract

The aim in antihypertensive therapy should be to lower the blood pressure gradually by using the safest, mildest, and least symptomproducing drugs; dosages are determined by patient observation over weeks or months of time. One of the various preparations of Rauwolfia should be used first, an effort being made to achieve the antihypertensive effect without depression. A second drug, Veratrum, may be added if extensive trial has shown the first alone to be inadequate. Again an effort is made to lower the blood pressure without side-effects; in the case of Veratrum these are usually nausea and vomiting, rarely cardiac arrhythmia and collapse. A third drug to be tried with Rauwolfia is hydralazine; it is a potent hypotensive drug, but it can have acute and chronic toxic effects. The fourth is chlorothiazide, which can, in addition to a desirable hypotensive effect, cause diuresis and quickly deplete the body of potassium. The dosage should be kept low and supplements of potassium should be given in patients receiving long-term treatment. A fifth class of available drugs are the ganglionic blocking agents, the dosages of which are so critical that especially exacting care is needed in adapting them to the individual case. Each class of drug may be used in combination with the others, but every change should be instituted gradually. By use of minimal effective doses of drugs in combination, a safe antihypertensive regimen can generally be developed.