Hexamethonium chloride is a quaternary ammonium halide. Its formula is:
Sometimes the bromide is employed and in England the iodide is preferred, but the chloride is the most commonly used salt.
In the United States hexamethonium is sold as Methium (Warner-Chilcott Laboratories), Hexameton (Burroughs Wellcome & Company), Esomid (Ciba Pharmaceutical Products, Inc.), Bistrium (E. R. Squibb & Sons), and others. It is also combined with such antihypertensive drugs as hydralazine (Apresoline) and rauwolfine.
The tetra-, penta-, and hexamethonium compounds act by blocking both the sympathetic and the parasympathetic ganglia. The block, which is carried out by competition, occurs at the synapse. Vasoconstriction and autonomie tone are thereby reduced or abolished. In addition to use of hexamethonium in hypertension, the drug is being widely used in surgery, particularly in extensive operations, to diminish bleeding. As might be expected in a drug that may cause a fall of blood pressure from 260/160
BRUCE GM. Permanent Bilateral Blindness Following the use of Hexamethonium Chloride. AMA Arch Ophthalmol. 1955;54(3):422-424. doi:10.1001/archopht.1955.00930020428014