Tobacco use began around 6000 BCE in North America before spreading to Peru and Ecuador. Early users claimed that the product was a good mosquito repellant

The pharmacology of cigarette smoking

The absorption of nicotine occurs in the upper airway (burns, 2008)

The psychoactive compound in tobacco is nicotine. Tobacco contains thousands of chemicals whose concentration influenced by:

1. The composition of tobacco being smoked
2. The density to which tobacco is packed
3. The length of the tobacco column being smoked
4. The characteristics of the filter
5. Temperature at which the tobacco is being smoked

Nicotine

First isolated by chemists in 1828, nicotine effects on the nervous system identified in 1889 Cigarette manufacturers increased the concentration of nicotine in the cigarettes by over 10% during 1998-2004.

Smoking introduces nicotine directly to the brain within seconds of inhalation. A single pack per day totals to 85,000 puffs per year=7000 cigarettes per year.

Drug interactions between nicotine and prescribed medications

The cytochrome p-450 pathway in the liver metabolizes nicotine, altering the pharmacokinetics of compounds like morphine. Results: smokers require more morphine for pain control

Smokers have

1. low plasma content of propranolol, haloperidol and doxepin at fixed dosages relative to nonsmokers
2. experience less sedation from doses of benzodiazepine
3. Metabolize marijuana rapidly than nonsmokers.
4. Women smokers under oral contraceptives at high risk for stroke, myocardial infarction and thromboembolism

Nicotine decreases blood levels of clozapine and haloperidol by 30-50% blocking:

1. The biotransformation of these compounds hence reducing their effectiveness
2. The biotransformation of antidepressant medication desipramine, doxepin and nortriptyline=raised blood levels of the compounds to dangerous levels.

The vasoconstriction effect of cigarette smoke=insulin dependent diabetics take longer to absorb transdermal insulin injections

Effects of nicotine on the smoker’s body

Nicotine highly toxic. Estimated lethal dose for adults is 40-60 mg

Symptoms of nicotine toxicity: nausea, vomiting, diarrhea, abdominal pain, headache, sweating & pallor

Oral overdoses cause: dizziness, weakness, confusion, coma, and death from respiratory paralysis

Nicotine stimulates the secretion of acetylcholine: this explains the nicotine’s effects on the cardiovascular system e.g. increased heart rate, BP, strength of heart contractions, reduced rate of stomach muscle contractions constriction of blood vessels of peripheral organs

Nicotine addiction

First admitted by tobacco companies in 1997 in the USA, the greater the person exposure to nicotine, the higher the chances of getting addicted to the substance

90-95% of smokers are addicted to the substance and show symptoms of drug addiction.

1. Tolerance
2. Withdrawal syndrome
3. Drug seeking behaviors

Nicotine withdrawal

Imitated within 2 hours of smoking, peak within 24 hours before declining over the next ten days

Symptoms include sleep problems, irritability, and impatience, low levels of concentration, lightheadedness, restlessness, fatigue, gastrointestinal upset, constipation, and headache and increased coughing.

Major smoking ailments and complications

1. The mouth, throat and pulmonary system: smokers at risk of respiratory disorders during sleep like snoring and obstructive sleep apnea, chronic bronchitis, pneumonia, chronic obstructive pulmonary diseases
2. The digestive system: skin responsible for most of gum diseases and tooth loss, throat and mouth cancer, gastric ulcers, peptic ulcers, stomach cancer and pancreatic cancer, type p diabetes
3. The cardiovascular system: heart diseases by altering the cardiac rhythm and reducing elasticity of cardiac muscle tissues, constricted heart arteries, Increased hypertension, the development of aortic aneurysms and atherosclerotic vascular diseases, Strokes,
4. The skin: smoking associated with premature aging
5. The central nervous system: a carcinogen found in tobacco causes inflammation and damage to brain neurons, speeds up damage in multiple sclerosis, amyotrophic lateral diseases
6. The reproduction system: erectile dysfunction in male smokers, interferes with normal reproductive system of the females
7. Other complications: causes exacerbate psoriasis.

Chewing tobacco

Tobacco can also be snuffed (dry or moist) and chewed= smokeless tobacco

Mostly done by on the assumption that it is safer than smoking

Chewed tobacco has 16 carcinogens, which cause mouth cancer and throat, fatal myocardial infarction, pancreatic cancer, coronary artery disease, high risk of oral and throat cancers and HBP.

Second-hand smoke

Definition: exposure to the cigarette smoke of a smoker: it causes cotinine, coronary artery constriction, atherosclerotic plaque, myocardial infractions, tuberculosis, cognitive impairment, fatalities in case of children, emphysema,

Smoking cessation

Most effective: never begin smoking.