Pharmacology of Smoking Flashcards
What are the dangers of cigarette smoking?
- Lung cancer
- Chronic obstructive pulmonary disease
- Cardiovascular disease
- Other cancers
What are the components of cigarette smoke?
- Nicotine (10-20mg per cigarette and addictive)
- Carcinogens (cancer causing)
- Particulates (10 micrometers to nanoparticles)
- Carbon monoxide (6-20x higher levels of carboxyhemoglobin in smokers than non-smokers)
- Free radicals
What are the different types of nicotinic receptors?
- N1 (ganglionic) receptors
- N2 (muscle type) receptors
- CNS type receptors
- CNS, ANS and NMJ
What are the peripheral effects of activating nicotinic receptors?
- Tachycardia
- Nausea
- Reduction of GI motility
- Sweating
- Decline with repeated dosage
- Central effects of nicotine
What does nicotine act on and what does it lead to?
- α-4-β-2 AChR in the CNS
- Release of neurotransmitters
- Dopamine, noradrenaline, acetylcholine, serotonin, glutamate, B-endorphin, GABA
- Effects produced by these Its tend to wear off in habitual smokers
What does the release of dopamine lead to?
- Pleasure and appetite suppression
What does the release of noradrenaline lead to?
- Appetite suppression and arousal
What does the release of acetylcholine lead to?
- Arousal and cognitive
What does the release of serotonin lead to?
– Appetite suppression and mood modulation
What does the release of glutamate lead to?
- Memory enhancement and learning
What does the release of β-endorphin and GABA lead to?
- Reduction in anxiety and tension
What is the effect of smoking on nicotinic receptors in the CNS?
- Nicotine in cigarette smoke rapidly taken up by pulmonary circulation
- Diffuses into CNS within 10-20 seconds
- Chronic nicotine administration increases number of AChR in CNS and also leads to desensitisation of receptors
- Reactivation of receptors is thought to be involved in craving and withdrawal
What other cancers can cigarette smoke lead to?
- Bladder, kidney and pancreas
What is COPD?
- Chronic obstructive pulmonary disease
- Umbrella term for chronic bronchitis, bronchiolitis and emphysema
- Conditions common in smokers
Describe the relationship between smoking and chronic bronchitis
- Mucus gland hypertrophy and hyperplasia
- Excess mucus (100-150 ml leads to smoker’s cough)
- Cilia damaged by oxidants and mucociliary escalator does not work efficient.y
- Patients tend to get frequent airways infection
- Optimum for pathogens (warm, moist and glucose rich)
Describe the relationship between smoking and bronchiolitis
- Inflammation of bronchioles
- Increased neutrophils, macrophages, and CD8 T cells
- Fibrosis and an increase in airway resistance
- Bronchiolitis can be seen in young smokers
- no evidence of aieqaay obstruction
Describe the relationship between smoking and emphysema
- Permanent enlargement of distal alveoli
- SA rescued, gas exchange compromised
- Elastin damaged–> premature closing of airways and air trapping
- Heterogenous disease- affects particular airways in lungs
- VQ mismatch
What are the systemic effects of smoking?
- Persistent, low-grade, systemic inflammation
- Endothelial dysfunction
- Activation of clotting pathways
- Increased carboxyhemoglobin levels (less oxygen delivery)
- Raised cholesterol levels (high and increased oxidised LDL)
- Raised blood pressure
What occurs in a persistent, low grade, systemic inflammation?
- Increased C reactive protein in plasma
- Increased plasma cytokines (TNF-α and IL-6)
- Increased fibrinogen leading to increased blood visit, platelet aggregation and fibrin formation
How does smoking lead to endothelial dysfunction?
- Decrease in NO production, therefore vasodilation
Outline some of the psychological aspects of smoking
- Cues for smoking
- Condition may maintain smoking behaviours, even after nicotine receptor desensitisation
- Peer pressure type influences
- Psychological factors are a major factor in relapse
What are the different methods of smoking cessation?
- Nicotine replacement therapy
- Anti-depressants- bupropion (Zyban)
- Nicotinic receptor partial agonist varenicline (CHampix)
- Nicotinic receptor antagonist- Mecamylamine (Inversine) associated with ANS-type side effects
- Behavioural support
What are the different forms of nicotine replacement therapy?
- Patches
- Gum
- Sublingual tablets
- Nasal spray
- Inhalators
What are the different types of behavioural support available for smokers?
- Nurse-led clinics
- Telephone support lines
- Hypnotherapy
