Tobacco Dependence

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Tobacco Basics - Puff Stats & Facts

  • India (GATS-2): 28.6% adults (267 million) use tobacco.
    • Smokeless tobacco (e.g., Khaini, Gutkha) most common: 21.4%.
    • Smoked tobacco (e.g., Bidis, Cigarettes, Hookah): 10.7%.
  • Key Harmful Constituents (beyond Nicotine):
    • Over 7000 chemicals; >70 carcinogens.
    • Major toxins: Tar, Carbon Monoxide (CO), Formaldehyde, Benzene.
    • Potent carcinogens: Tobacco-Specific Nitrosamines (TSNAs), Polycyclic Aromatic Hydrocarbons (PAHs). Other Tobacco Products

⭐ Tobacco use is a leading cause of preventable death and disability in India.

Nicotine's Nasty Knack - Brain Hijack

  • Mechanism: Nicotine mimics acetylcholine, binding to nicotinic acetylcholine receptors (nAChRs), primarily in the ventral tegmental area (VTA).
  • Reward Pathway Activation:
    • Stimulates dopamine (DA) release in the nucleus accumbens (NAc).
    • Reinforces drug-seeking behavior. 📌 Dopamine Drives Desire.
  • Neuroadaptation:
    • Chronic use leads to ↑ nAChRs (especially $\alpha4\beta2$ subtype).
    • Results in tolerance & withdrawal symptoms (e.g., irritability, anxiety).
  • Pharmacokinetics:
    • Rapid absorption; quickly crosses the blood-brain barrier.
    • Short half-life: ~2 hours, prompting frequent use to maintain effects. Nicotine effect on dopamine reward pathway

⭐ The $\alpha4\beta2$ nicotinic acetylcholine receptor subtype is crucial for mediating nicotine's addictive effects and is a key target for some smoking cessation therapies.

Caught in the Cloud - Signs & Scales

  • DSM-5 Tobacco Use Disorder:2 criteria in 12 mo: impaired control (craving, ↑use), social impairment, risky use, pharmacological (tolerance, withdrawal).
  • Nicotine Withdrawal: Onset: hours, Peak: 24-48h, Duration: weeks.
    • 📌 CRAVING: Craving, Restlessness, Anxiety, Vexation (Irritability), Insomnia, Nervousness, GI upset/↑Appetite.
  • Fagerström Test (FTND): Score 0-10.
    • Interpretation: Low (0-3), Moderate (4-5), High (≥6) dependence.
    • Key Qs: Time to First Cigarette (TTFC), cigarettes/day (CPD).

⭐ Time to first cigarette (TTFC) after waking is a strong predictor of nicotine dependence severity in the Fagerström test.

Kicking the Habit - Pills & Patches

DrugMOADose (Examples)SECIEfficacy
NRTNicotine agonistPatch: 7-21mg; Gum: 2/4mgLocal irritation, GI upsetRecent MI (rel.)~2x
Bupropion SRNA/DA RI, nAChR antag.150mg ODBD (max 300mg)Insomnia, dry mouthSeizures, eating dis.~2x
VareniclinePartial $\alpha4\beta2$ nAChR agonist0.5mg ODBD1mg BDNausea, NP SEsSevere renal impair.~3x

⭐ Varenicline has the highest single-agent efficacy for smoking cessation.

Mind Over Matter - Talk & Tactics

Behavioral counseling is a cornerstone for cessation.

  • 📌 5 A's Model: (Illustrated above) Ask about use; Advise to quit; Assess willingness; Assist with plan; Arrange follow-up.
  • 📌 5 R's Model: For unmotivated smokers, to enhance motivation:
    • Relevance: Personalize reasons to quit.
    • Risks: Outline negative consequences.
    • Rewards: Highlight benefits of quitting.
    • Roadblocks: Identify and address barriers.
    • Repetition: Reinforce at every opportunity.
  • Motivational Interviewing (MI): Collaborative approach to enhance intrinsic motivation. Core principles: Express Empathy, Develop Discrepancy, Roll with Resistance, Support Self-Efficacy (EDRS).

⭐ Combining pharmacotherapy with behavioral counseling significantly ↑ quit rates and is the most effective approach.

High‑Yield Points - ⚡ Biggest Takeaways

  • Nicotine addiction targets nicotinic acetylcholine receptors (nAChRs).
  • Withdrawal symptoms (craving, irritability) peak in 1-2 days.
  • Varenicline (partial nAChR agonist) is a first-line pharmacotherapy.
  • Bupropion and Nicotine Replacement Therapy (NRT) are also key first-line options.
  • The 5 A's (Ask, Advise, Assess, Assist, Arrange) guide counseling.
  • Strong links to COPD, lung cancer, and cardiovascular disease.
  • Fagerström test quantifies dependence severity.

Practice Questions: Tobacco Dependence

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In which of the following conditions is behavioral therapy most commonly utilized?

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Flashcards: Tobacco Dependence

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A patient of delirium tremens will have features of _____kalemia, hypomagenesemia, hypovolemia and hypophosphatemia

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A patient of delirium tremens will have features of _____kalemia, hypomagenesemia, hypovolemia and hypophosphatemia

hypo

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