Nicotiana tabacum. Tobacco. N.O. Solanaceae. Tincture of the fresh leaves collected before the flowers are developed.
TOBACCO owes its effects to an alkaloid, nicotine (C10H14N2) which is a volatile fluid, with strong alkaline reaction, and forms salts with acids. In dried tobacco it is accompanied by a volatile oil, developed during the processes of preparation of the leaves, to which the odour and flavour of tobacco are due.
Very large doses of nicotine may prove fatal within a few seconds from sudden paralysis of the central nervous system, including the respiratory tract.
Smaller, but still toxic doses, cause a hot, burning sensation in the mouth (which spreads down the oesophagus to the Mental confusion, giddiness, muscular prostration and loss of co- ordinating power come on. The breathing is quick, deep and laboured, the pulse slow at first, but afterwards weak and rapid. Partial or complete unconsciousness supervenes and later fibrillary twitchings of muscles and clonic convulsions; eventually death occurs from arrest of respiration in a tetanic spasm, or respiration may cease without the intervention of tetanus.
Post-mortem examination shows the medulla and brain congested, the gastric mucous membrane ecchymosed, the intestines contracted and their mucous membrane vividly injected in places, the bladder contracted and empty, and the blood black and semi- fluid.
Nicotine first stimulates and then paralyses the ganglia on the pneumo-gastric nerve to the heart, the ganglia on the vaso- constrictor nerves, the ganglion cells on the chorda tympani, and all the sympathetic ganglia. It acts on the respiratory centre directly, first stimulating and then paralysing it. It causes tetanic contraction of the stomach and of the muscular walls of the entire alimentary tract; this alternates with relaxation. It similarly tetanizes the bladder. The pupils are first contracted and then dilated. It stimulates the central nervous system, exaggerating the irritability of the spinal cord, and so increase reflex action, and has a still more stimulating effect on the medulla and cerebellum. Nicotine is excreted mainly by the kidneys, but has been detected also in the saliva and perspiration.
It is a functional rather than an organic poison, and when patients survive a large dose of nicotine they quickly regain their normal condition.
When tobacco is smoked nicotine is taken by inhalation along with carbonic acid, carbonic oxide and several ammonias. Tobacco is also chewed and swallowed and taken in the form of snuff. The effects produced by these practices cause various symptoms that appear more readily in some subjects than in others. A first attempt at smoking is commonly followed by some of the milder symptoms caused by poisonous doses, such as deathly nausea, vomiting, giddiness, pallor, prostration and cold sweat all over the body. After this, tolerance is usually established. Habitual smoking to excess brings with it certain functional derangements. These are (a) a dry, red and irritable throat; the larynx is irritated, which causes hawking and scraping and the secretion of mucus, the condition known as “smokers’ sore throat.” (b) The innervation of the heart is disturbed, the pulse becomes weak, irregular and intermittent, palpitation, praecordial pains, faintness and vertigo occur and form the symptoms of “tobacco heart.” (c) In the young the processes of nutrition are interfered with and the growth is stunted. (d) The sexual organs are at first stimulated, but eventually weakened and virile power is lost.
(e) Vision is impaired and the “tobacco amblyopia” is produced. This a toxic amblyopia which affects a limited portion of the retina of oval shape, with its long diameter horizontal; it lies between the inner margin of the macula and the optic nerve, which, when projected, corresponds to the portion of the field of vision that lies between the inner side of the blind spot and the outer side of the point of fixation. This is supplied by a special bundle of nerve fibres, the papillo-muscular bundle. Sense for both form and colour is deficient over this area, the colour defect being most marked for red and green. There is no contraction of the field of vision and the rest of the retina is unaffected; this accounts for the fact that people with tobacco amblyopia see worse in a strong light as the contraction of the pupils caused by it shuts off rays that co-ordination is impaired, and very fine and exact work is rendered impossible of performance. (g) Nervous symptoms, such as tremors and exaggerated reflexes, sometimes occur. (h) The power of intellectual concentration is lessened. These symptoms, including the amblyopia, usually disappear quickly when the habit of smoking is left off, but in a few cases atrophy of the optic nerve has resulted.
There are some additional symptoms elicited by the provings, such as toothache.
Digestion.-The crowns of the teeth remain healthy, but the fangs are denuded of their periosteum, are porous and rough at the extremities, the teeth become tender, and if bitten on acute pain is felt, throbbing pain comes on which is aggravated by sudden changes to heat or cold and from alcohol. A sensation of constriction in the oesophagus has been noticed. Violent hunger is sometimes experienced. Nausea and vomiting are made worse by motion, and better by fresh, cool air. Eructations are vomited matters are sour. There is spasmodic pressure in the epigastrium, or a sinking sensation as if the stomach is hanging down relaxed (ipec., staph.). Gurgling occurs in the bowels with shifting of flatus, and there may be violent contractions in the abdominal muscles, with retraction of the navel. The stools are sudden, papescent and of yellow-green colour and are accompanied by tenesmus; vomiting often occurs simultaneously with stool.
Sexual.-Nocturnal emissions are frequent.
Circulation.-Paroxysms of suffocation may take place, and tightness across the upper part of the chest, with violent palpitation and angina pectoris; also praecordial oppression in paroxysms with palpitation felt between the shoulders.
Limbs.-Cramps occur in the arms and hands, which tremble and are icy cold. The legs from the knees downwards are cold, and the feet are weak and tremble. Cold sweat and cramps affect all the limbs. The body emaciates, especially the back and cheeks.
Circulation.-Tabacum has had a limited therapeutic use. It has been employed principally for functional heart affections, such as acute dilation of the heart caused by shock or violent physical exertion; for cardialgia; for attacks of palpitation; for the intermittent heart of old people, and for the insomnia of dilated heart. The high dilutions will counteract the disorder of “tobacco heart” brought on by excessive smoking.
It is a remedy for cardialgia, when the pain begins at the cardiac end of the stomach, and runs over the shoulder to the left arm. Attacks of pseudo-angina pectoris can be controlled by
Digestion.-Tobacco in material doses counteracts the sinking at the stomach caused by fasting, and enables the patient to go on fairly comfortably without a meal. The vomiting, painless purging, liquid stool, cold sweat and prostration indicate it in cholera and cholera infantum, in both of which it has proved valuable. It is useful for toothache of the kind already described.
Another use of tobacco has been for sea-sickness, the symptoms of which are very similar to those of the drug.
Its peculiar influence on the retina led Dr. Alexander to give it in a case of blindness with curative effect.
(1) Great sinking at the stomach.
(2) Muscular prostration and faintness.
(3) Mental concentration lessened.
(4) Relaxation of sphincters.
(6) Nausea, vomiting and cold sweat.
(8) Contraction alternating with relaxation of unstriped muscle.
(9) Functional cardiac affections. Pseudo-angina pectoris.
(10) Cholera infantum. Sea-sickness.
From motion, pressure, warm room, alcohol, lying on side left (palpitation),strong light (vision).
From vinegar, cold to heat, open air, vomiting, uncovering abdomen (nausea and vomiting).