Nicotiana Tabacum (Tobacco): A Cardiac Poison
All parts are poisonous except die ripe seeds. The dried leaves (tambaku) contain one to eight percent of nicotine and are used in the form of smoke or snuff or chewed. The leaves contain active principles, which are the toxic alkaloids nicotine and anabasine (which are equally toxic); nornicotine (less toxic). Nicotine is a colorless, volatile, bitter, hygroscopic liquid alkaloid. It is used extensively in agricultural and horticultural work, for fumigating and spraying, as insecticides, worm powders, etc.
Climbing plant found in tropical forests with long, woody rope-like stems of anomalous anatomical structure. Tobacco flowers are organized in panicles. They have a tubular shape with 5 fused petals that flar at the mouth into 5 distinct lobes. They are fragrant and range in color from white to a very light pink, purple, or yellow. It is important to note that nicotine-product users moderate their use of the products to adjust the level of their effects: smokers can hold the smoke less long, let the cigarette burn longer between inhalations, etc.
Absorption and Excretion: Nicotine is rapidly absorbed from all mucous membranes, lungs and the skin. Eighty to ninety percent is metabolized by the liver, but some may be metabolized in the kidneys and the lungs. It is excreted by the kidneys.
Action: It acts on the autonomic ganglia which are stimulated initially, but are depressed and blocked at later stage. It also acts on the somatic neuromuscular junction, and afferent fibers from sensory receptors.
It is the most widely grown commercial non-food plant in the world. It holds a high importance in financial and economic policies in many countries. Consumption is by way of smoking, inhaling or chewing and is a habit forming narcotic, and although bans of its use have been attempted, its consumption marches steadily forward.
Nicotine is the primary psychoactive constituent of tobacco. It is found in cigarettes, chewing tobacco, and rolling tobacco, as well as in nicotine patches, gum, inhalers, and nasal spray. Tobacco has a long history of use by medical herbalists as a relaxant, though since it is a highly additive drug it is seldom employed internally or externally at present. The leaves are antispasmodic, discutient, diuretic, emetic, expectorant, irritant, narcotic, sedative and sialagogue. They are used externally in the treatment of rheumatic swelling, skin diseases and scorpion stings. The plant should be used with great caution, when taken internally it is an addictive narcotic.
Acute Poisoning: G.I.T. Burning acid sensation, nausea, vomiting, abdominal pain, hyper salivation. Ingestion of parts of the tobacco plant may cause various symptoms and severe cases may result in a coma.
Cardiopulmonary: Tachycardia, hypertension, tachyapnoea, (early); bradycardia, hypotension, respiratory depression (late). -Cardiac arrhythmias may occur. C.N.S.: Miosis, confusion, headache, sweating, ataxia, agitation, restlessness, hyperthermia (early); mydriasis, lethargy, convulsions, coma (late). Death may occur from respiratory failure.
Chronic Poisoning: Symptoms are cough, wheezing, dyspnoea, anorexia, vomiting, diarrhea, anemia, faintness, tremors, impaired memory, amblyopia, and blindness, irregularity of the heart with extra systoles and occasionally attacks of pain suggesting angina pectoris.
Withdrawal Symptoms: Intense urge to smoke, anxiety, impaired concentration and memory, depression or hostility, headache, muscle cramps, sleep disturbances, increased appetite and weight gain, diaphoresis and rapid respirations.
Nicotine replacement therapy (NRT) includes use of nicotine products including gum, transdermal patch, nasal spray, lozenge and inhaler.
Fatal Dose: Sixty to hundred mg. of nicotine. It rivals cyanide as a poison capable of producing rapid death; fifteen to thirty g. of crude tobacco.
Smoked Nicotine Dosages:
Threshold : 0.2 - 0.3 mg
Light : 0.3 - 0.8 mg
Common : 0.6 - 1.5 mg
Strong : 1 - 2 mg
Heavy : 2 - 4 mg
Fatal Period: Five to 15 minutes.
The Circumstances of Poisoning: Accidental poisoning results due to ingestion, excessive smoking and application of leaves or juice to wound or skin. For malingering tobacco leaves are soaked in water for some hours and placed in axillae at bed time, which is held in position by a bandage. Poisonous symptoms are seen the next morning. Suicidal and homicidal poisoning is rare.