Aconitia. (Aconitine.) An Alkaloid, C60H47 NO14, obtained from the root of Aconitum Napellus.
Med. Prop, and Action. Sedative poison, too powerful for internal use. In man and animals its action seems directed to the nervous system, and through it to the heart. Sensation is lost; there is staggering gait and inability to walk; the heart's action becomes gradually slower, and death takes place by asthenia. l-50th of a grain is sufficient to poison a large dog, and the same quantity has proved nearly fatal in man. Very minute doses produce heat and tingling of the surface, and sometimes diuresis. Externally it may be applied in the form of ointment or solution. The Unguentum Aconitia of the Brit. Ph. contains Aconitia grs. viij., Rect. Sp. fl. drm. ss., Prepared Lard oz. j. Dr. Fleming's ointment consists of Aconitia grs. xvj., Rect. Sp. exvj., Lard 3j. An alcoholic solution consisting of grs. viij. to fl. oz. ij. of Rect. Sp. has also been used as an external application. When rubbed on the skin, in the form of ointment or solution, it produces a sensation of heat and pricking, succeeded by a feeling of numbness and constriction of the part, as if a heavy weight were laid upon it, or as if the skin were drawn together by the powerful and involuntary contraction of the muscles beneath. This sensation lasts from two to twelve hours, according to the quantity rubbed in. It produces very slight, if any, vascular excitement, not more than may very easily be accounted for by the friction itself. (Turnbull.*) Dr. Fleming states, that when his Aconite ointment is applied to the conjunctiva, it produces contraction of the pupil; but that when applied to the temples and forehead, it produced, in two instances, dilatation of the pupil, attended with partial blindness. In consequence of its high price, it has been frequently adulterated, and is found almost inert. The method of preparing it recommended in the British Pharmacopoeia, however, insures the full activity of the drug. Care should be taken not to apply the ointment or solution of Aconitia where the skin is abraded. Offic. Prep. Ung. AconitiAe (Aconitia gr. viij.; Rect. Sp. exxx.; Lard oz. j.).
* Cyc. Pract. Med., vol. iii. p. 548. Op. cit., p. 336.
Lond. Journ. of Med., July 1851. § Illust.of Acoustic Surg.,Lond. 1825.
In Tic Douloureux, Sciatica, Lumbago, and other neuralgic affections, and also in some forms of Rheumatism and Gout, Aconitine, locally applied over the seat of pain, is one of the most certain and powerful palliatives in the Materia Medica. Dr. Thompson states that he found it peculiarly effectual in several instances of cubito-digital and frontal neuralgia; and Mr. Skey relates two cases, one of eight years' and the other of nine years' duration, which were relieved by it, when all other remedies had failed. The arrest of pain is only temporary in most cases; but even this, when the pain is intense, is an advantage of no inconsiderable importance. It may be applied in the form of ointment or solution (ante), and it should be rubbed in over the affected part, until the pain is relieved. Dr. Turnbull, § who introduced it into practice, advises the proportion of Aconitine to be increased at every second or third friction. Dr. Watson|| quotes a case, which resisted the use of Aconitine, until it was combined with a saturated solution of Iodine, when a complete cure was effected.