NITRITES (including AMYL-NITRITE). —The nitrites may be divided into two grotips: the inorganic, or mineral, in cluding the nitrites of sodium (officinal), barium, calcium, potassium, strontium, and the compound salt of cobalt and potassium; and the organic group, which contains the nitrites of methyl, ethyl, propyl, butyl, and amyl (officinal). These latter may be subdivided into primary, isoprimary, secondary, and tertiary ni trites.
Sodium nitrite occurs as colorles.s, transparent, hexagonal crystals having a mildly-saline taste. It is soluble in 1 V, parts of water and slightly soluble in alco hol. lt should be kept in a well-stop pered bottle.
Barium nitrite occurs as a white, crys talline powder or as colorless prisms. It is soluble in water and in alcohol.
Calcium nitrite occurs as deliquescent prisms or in yellowish masses. It is freely soluble in water.
Potassium nitrite occurs as white, amorphous, deliquescent sticks.
Strontium nitrite occurs as a white powder, soluble in water.
Cobalt and potassium nitrite (cobalt yellow) occurs as a yellow, microerystal line powder, which is slightly soluble in water.
Ethyl-nitrite (nitrous ether) occurs as a yellowish, highly-aromatic, ethereal, inflammably, and exceedingly-volatile liquid. It is used in the form of a spirit (spirit of nitrous ether). When added to water it rapidly disintegrates, and should not be mixed before using.
Amyl-nitrite (iso-amyl-nitrite) occurs as a yellowish, transparent, very dif fusive, unstable liquid, having a pene trating, fruity odor. It is soluble in chloroform, alcohol, and ether. It should be kept away from the fire and the light in a dark, well-stoppered bottle.
Preparations and Doses.—Amyl nitris, U. S. P., 2 to 4 minims by inhalation from a handkerchief or given in brandy.
Potassii nitris, V, to 2 grains.
Potassii cobalto-nitris, V, to 1/2 grain. Sodii nitris (U. S. P.), 1/2 to 2 grains. Spiritus mtheris nitrosi (U. S. P.; alco holic solution of ethyl-nitrite), 1/., to 4 fluidrachms.
Physiological Action.—An important feature of the influence of amyl-nitrite is that upon the circulation. The effect
upon the pulse begins a few seconds after inhalation; the arterial tension is low ered to the utmost point in from 40 to 60 seconds, remains extremely low for 30 seconds, then rises suddenly, and 1. minutes afterward is only a little lower than it was before the inhalation. A small dose of sodium nitrite (2 grains) distinctly affects the pulse in from 2 to 3 minutes; the point of the lowest ten sion is reached in from 8 to 20 minutes, and any noticeable influence ceases in from 2 to 3 hours. Slowness and irregu larity of the pulse, with slight intermis sions, are sometimes observed, but these irregularities become less, or entirely disappear, soon after the administration of the drug. The nitrites, in very small amounts, affect the circulation. Thus, 7,6 grain will produce a marked action in most people. Experimental evidence appears to have shown that under the in fluence of the nitrites the lungs are tem porarily dilated, the work of the right heart being thus relieved to a certain ex tent. Again, they do not markedly in fluence the function of the kidneys, there being no alteration in the flow of urine, notwithstanding that the renal vessels are dilated. Neither do they exercise any noticeable influence on the temperature, except when given in toxic amounts. The organic nitrates and the nitrites possess similar properties, this being due to the probable conversion of the nitrate-molecule into the nitrite-mole cule. (Leech.) Nitrite of amyl influences the circula tion, mainly by paralyzing the muscular supply, but markedly stimulates the heart in every way. This tends to in duce cardiac paralysis and arrest in dias tole if the administration be unduly pro longed. It also causes excitement of the motor functions and a slight paresis of the sensory processes (Kraepelin). This is followed by loss of motor activity in s f and paralysis of res.! ry ntrts. 'rile blood is also af t, tit], mtt hxmoglobin being formed out ci rpusLular hxmoglobin.