Aconitina, B.P., Aconitine.
C34H47NO11 = 645.386.
Aconitine, C34H47NO11, is an intensely poisonous alkaloid obtained from aconite root. The B.P. formula for aconitine, C33H45NO12, has been proved, by investigation, to be incorrect. The U.S.P. gives the correct formula. It occurs in colourless crystals. Melting-point, 204° to 205°; when heated rapidly; if heated slowly it decomposes, and melts at 182°. If 1 centigram be evaporated with 2 ½ decimils (0.25 milliliters) of fuming nitric acid, and the residue, after cooling, treated with alcoholic potassium hydroxide solution, no violet colour should be produced (difference from pseudaconitine and atropine). If 1 milligram be warmed on a water-bath for five minutes with 2 to 4 drops of sulphuric acid, specific gravity 1.75, and a crystal of resorcin then added the liquid assumes a reddish-violet colour in about twenty minutes.
Readily soluble in alcohol or chloroform, less soluble in ether, almost insoluble in water.
Action and Uses.—Aconitine has a very characteristic effect on sensory nerve endings. Applied to the tongue it produces a tingling sensation, followed by numbness and, later, anaesthesia. It is not absorbed from the unbroken skin, but when applied with alcohol or fat the typical tingling followed by numbness is present. When taken by the mouth the same excitation of the sensory endings is induced, and this is especially marked in the more sensitive parts of the body, such as the tongue, throat, and finger-tips. This action has led to its employment in trigeminal neuralgia. The medulla is first excited and then depressed. Hence, after small doses, respiration is increased in depth and frequency, the pulse becomes slower and the peripheral vessels tend to constrict, but the blood pressure does not rise on account of the decided cardiac slowing. Very large doses quicken the heart and ultimately send it into the condition known as delirium cordis. It produces a marked fall in temperature both in fever and in normal conditions. Aconitine is rarely given internally, on account of its extremely powerful cardiac action. It is used locally as an ointment to relieve neuralgic pains. In cases of poisoning by this alkaloid, apply the treatment described under Aconiti Radix.
Dose.—1/10 milligram (1/640 grain).
- Chloroformum Aconitinae, B.P.C.—CHLOROFORM OF ACONITINE.
- Aconitine, 0.23; chlorophyll paste, 0.05; chloroform, to 100.
- Collodium Anodynum, B.P.C.—ANODYNE COLLODION. Syn.—Anodyne Colloid.
- Aconitine, 0.11; veratrine, 0.68; acetone, 30; acetone collodion, to 100.
- Oleinatum Aconitinae, B.P.C.—OLEINATE OF ACONITINE. Syn.—Oleatum Aconitinae; Oleate of Aconitine. 1 in 50.
- Applied sparingly over the seat of pain in neuralgia, and in acute rheumatism. It must not be applied to abraded surfaces.
- Unguentum Aconitinae, B.P.—ACONITINE OINTMENT.
- Aconitine, 2; oleic acid, by weight, 16; lard, 82. A piece the size of a bean is applied to relieve neuralgic pain, especially in the face; it is also used to allay the pain of sciatica and acute rheumatism. It must not be brought into contact with mucous membranes or with abraded surfaces.