Tobacco, consumed mainly through smoking and smokeless forms, contains nicotine—an addictive alkaloid responsible for dependence and toxicity. Tobacco use is a leading preventable cause of disease worldwide, contributing to cardiovascular, respiratory, and cancer-related morbidity. Understanding nicotine pharmacology, acute and chronic toxicity, and cessation strategies is essential in clinical toxicology and public health.
Active Component: Nicotine
Nicotine is a potent stimulant and the primary addictive compound in tobacco. It acts on:
- Nicotinic acetylcholine receptors (nAChRs) in the brain
- Autonomic ganglia in the peripheral nervous system
- Neuromuscular junctions
Mechanism of Action
- Stimulates nicotinic receptors → dopamine release → reward and addiction
- Activates sympathetic system → tachycardia, hypertension
- High doses cause receptor blockade → neuromuscular weakness
Forms of Tobacco
- Cigarettes
- Cigars
- Chewing tobacco
- Snuff
- E-cigarettes and vaping products
Acute Nicotine Toxicity
Common in accidental ingestion by children or excessive e-cigarette use.
Symptoms
- Nausea and vomiting
- Salivation
- Abdominal pain
- Dizziness and headache
- Tachycardia or bradycardia
- Hypertension
- Tremors and seizures (high doses)
- Respiratory failure in severe poisoning
Chronic Toxicity of Tobacco Use
Respiratory System
- Chronic bronchitis
- Emphysema (COPD)
- Increased respiratory infections
Cardiovascular System
- Atherosclerosis
- Myocardial infarction
- Stroke
- Peripheral vascular disease
Cancer Risk
Tobacco smoke contains carcinogens including benzene, nitrosamines, and polycyclic aromatic hydrocarbons.
- Lung cancer (most common)
- Oral and throat cancers
- Esophageal cancer
- Pancreatic cancer
- Bladder cancer
Reproductive and Fetal Effects
- Reduced fertility
- Low birth weight
- Preterm birth
- Increased SIDS risk
Effects of Smokeless Tobacco
- Gum recession
- Oral leukoplakia
- Oral cancers
Diagnosis
- Clinical history and symptoms
- Cotinine levels (nicotine metabolite) for exposure assessment
Management of Acute Nicotine Poisoning
- Activated charcoal within 1 hour of ingestion
- Atropine for excessive salivation or bradycardia
- Benzodiazepines for seizures
- Supportive care and monitoring
Tobacco Dependence & Withdrawal
Withdrawal Symptoms
- Irritability and anxiety
- Craving for nicotine
- Increased appetite
- Insomnia
- Depressed mood
Management of Dependence
Nicotine Replacement Therapy (NRT)
- Gums
- Patches
- Lozenges
- Inhalers
Medications
- Bupropion – reduces craving
- Varenicline – partial nicotinic receptor agonist
Counseling & Behavioral Strategies
- Education on health risks
- Motivational interviewing
- Structured cessation programs
Prevention & Public Health Measures
- Smoking cessation campaigns
- Warning labels on cigarette packs
- Banning indoor smoking
- Restricting youth access to tobacco
Detailed Notes:
For PDF style full-color notes, open the complete study material below:
PATH: PHARMD/ PHARMD NOTES/ PHARMD FOURTH YEAR NOTES/ CLINICAL TOXICOLOGY/ TOBACCO.