Circulatory Effects of Guanethidine

Guanethidine, a new synthetic hypotensive drug that probably interferes with release of norepinephrine from sympathetic nerve endings and that does not inhibit parasympathetic activity, has proved an effective agent in reducing blood pressure in 25 hypertensive patients studied for periods up to 6 months. Untoward effects have been limited to orthostatic hypotension and mild diarrhea. The drug apparently lowers blood pressure by reduction in cardiac output rather than by relaxation of the arterioles. Reduction in renal blood flow and glomerular filtration rate accompanied administration of the drug, but in no case did progressive azotemia or oliguria occur. This agent is an extremely potent hypotensive drug with a remarkably prolonged duration of action and with none of the parasympatholytic side effects produced by ganglionic-blocking agents.