Nicotine

Question 1

Nicotine: action

Answer 1

• alkaloid
• agonist at nicotinic cholinergic receptors
  
  • receptors desensitize after brief nicotine exposure (unique to nicotinic receptors)
• Stimulant
• Rapidly absorbed through lung membranes into blood
• T1/2 = 1.5 hrs (short)
• Metabolized in liver via CYP2A6 pathways
• Very addictive (30% risk w/ exposure)

Question 2

Nicotinic ACh receptors (NAchRs)

Answer 2

• different combinations of subunits = different functions
• located throughout brain
• on pre-synaptic neuron
  
  • modulate neurotransmitter (including dopamine) release
• on post-synaptic neuron
  
  • modulate response of the post synaptic neuron to that neurotransmitter

Question 3

Brief intervention

Answer 3

• feasible: many smokers see a physcian at some point
• efficient: simply recommending stopping increases quit rates
• Set a quit date - 2 weeks from visit
• Brief counseling for them to prepare for that date
• Emphasize complete abstinence
• Prescribe pharmacotherapy to maintain abstinence

Question 4

Intensive counseling

Answer 4

• CBT
• motivational interviewing
• may be better for more addicted pts

Question 5

Nicotine gum

Answer 5

• OTC
• Fixed dose, 1 piece every 1-2 hrs for 12 weeks
• Adverse effects
  
  • from incorrect use (often not enough or swallowing gum)
  • GI irritation

Question 6

Nicotine patch

Answer 6

• 21 mg for 24 hrs; 15 mg for 16 hrs; 8-12 weeks
• OTC
• doesn’t fully replace nicotine for heavy smokers (only 50%)
• contraindicated for pts w/ skin disease

Question 7

Nicotine inhaler

Answer 7

• 10mg/cartridge
• vaporizes the nicotine
• Rx only
• use > 6 cartridges per day
• Nasal mucosa irritation
• delivers large amount of nicotine, potential to be abused

Question 8

Nicotine nasal spray

Answer 8

• 1-2 sprays per nostril per hour; 8 doses per day
• 12 weeks
• prescription only
• relieves nicotine withdrawal
• nasal irritation

Question 9

Bupropion SR (Zyban)

Answer 9

• same drug as welbutrin (anti-depressant)
• showed high % of abstinence compared to placebo over 1 yr

Question 10

Varenicline

Answer 10

• Partial agonist at NAchR subtype linked to reward in nicotine addicts
• relieves craving, withdrawal symptoms
• blocks satisfaction and rewarding effects of nicotine (blocks binding of nicotine to receptor)
• better than either placebo or zyban
• tx time = 8-10 weeks
• adverse effects:
  
  • nausea (most common)
  • depression
  • Cardiovascular events
  • ** not too severe or common compared to the adverse effects of smoking for prolonged periods