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MBBS - Year 1 > Physiology - Pharmacology and Patient Safety > Flashcards

Physiology - Pharmacology and Patient Safety Flashcards

1
Q

Facts about nicotine

A

Naturally occurring plant alkaloid
Found primarily in solanasceous plants
Principal source was tobacco and replacement therapy
Pure nicotine is a clear liquid w/ characteristic odour, turns brown on exposure to air

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2
Q

Absorption of nicotine

A

Nicotine is a wek base (pKa = 8.0)

Absorption through mucous membrane is pH dependent and increases as pH increases

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3
Q

Where can nicotine be absorbed through

A 
Oral cavity (absorption poor)
Skin 
Lung 
Urinary bladder 
GI tract (poor absorption due to low pH)
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4
Q

Main absorption of nicotine in cigarette smoke

A

Through funds

pH of alveoli is 7.4 so nicotine from cigar smoke is unchanged and easily crosses alveolar membrane into blood

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5
Q

Exposure to nicotine

A

Bad breath
Stained teeth
Smoker’s cough
Increased heart rate and bp

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6
Q

Bad breath - exposure to nicotine

A

Nicotine and other chemicals in tobacco gets deposited in oral cavity

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7
Q

Stained teeth - exposure to nicotine

A

Sticky substances in the smoke get deposited on teeth and thus causes stains

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8
Q

Smoker’s cough - exposure to nicotine

A

Coughing is a protective physiological mechanism to remove irritants from the body, esp from the respiratory tract

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9
Q

Increased heart rate and bp - exposure to nicotine

A

Short term effect

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10
Q

Nicotine metabolism

A

Occurs in liver within 1-2hrs in humans
70-80% gets oxidised to cotinine by oxidation
50% is excreted in urine
Nicotine can also be excreted via faeces, bile, saliva, sweat

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11
Q

Cotinine

A

Inactive metabolite of nicotine

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12
Q

Nicotine effects on whole organism

A 
Increased hr 
Cardiac contractility 
Increased bp 
Decreased blood temp 
Mobilisation of b mood sugar 
Increase in FFA in blood
Increase catecholamines levels in blood 
Arousal or relaxation
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13
Q

FFA

A

Free fatty acids

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14
Q

Catecholamines

A

Adrenaline

Noradrenaline

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15
Q

Nicotine effects on cellular level

A

Increased synthesis and release of hormones
Activation of tyrosine hydroxylase
Activation of several transcription factors
Induction of heath shock proteins
Effects of apoptosis
Induction of chromosome aberrations
Induction of sister chromatid exchange

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16
Q

Effects of nicotine on the autonomic nervous system

A

Reduces/ inhibits effects of parasympathetic activation

Tends to increase/ activate sympathetic activation

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17
Q

Why does nicotine effect the autonomic nervous system in the way it does

A

Parasympathetic endings release Ach and sympathetic endings relate NA (NE)

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18
Q

Ach

A

Acetylcholine

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19
Q

NA

A

Noradrenaline

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20
Q

NE

A

Norepinephrine

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21
Q

Cholinergic receptors

A

Receptors on the surface of cells that get activated when they bind to a type of acetylcholine

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22
Q

AChR

A

Ligand-gated ion channels and are present at the neuromuscular junction and signal muscular contraction with stimulation

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23
Q

Structure of nAChR

A

Composed of 5 subunits, 2 alpha, and one each of beta, delta and gamma subunits
All subunits arranges in barrel or cylindrical shape around a central pore
Each alpha subunit has a Ach binding site

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24
Q

How do nAChR’s work

A

Each of two alpha subunits have to be bound to Ach to allow influx of Ca2+ and Na+ intracellularly and efflux of K out of cell

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25
Q

Types of cholinergic receptors

A

Nicotinic (nAChR)
Muscarinic (mAChR)

Named after drugs that work on them

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26
Q

Nicotinic acetylcholine receptors

A

Pentameric ligand-gated ion channels

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27
Q

Muscarinic acetylcholine receptors

A

Seven-helix G-protein coupled membrane protein

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28
Q

Peripheral effects of nicotinic receptor activation

A

Increase in heart rate (HR), cardiac output (CO) and arterial pressure
Reduction in GI motility
Sweating

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29
Q

What does the peripheral effects of nicotinic receptor activation result from

A

Stimulation of autonomic ganglia and peripheral sensory receptors mainly in heart and lungs

30
Q

What does nicotine act on

A

Nn receptors

(alpha4) 2(beta2)3 - brain cortex & hippocampus - role in cognitive function
(alpha3) 2(beta4)3 – ganglion
(alpha1) 2beta1deltaepsilon - muscle

31
Q

What does smoking increase the risk of

A

Coronary heart disease (Myocardial Infarct)
Peripheral vascular disease (hypertension)
Lung cancer (carcinogens, tar & CO)
Chronic Obstructive Pulmonary Disease
Abnormal foetal development (low birth weight

32
Q

COPD

A

Chronic obstructive Pulmonary Disease

Incl chronic bronchitis and emphysema

33
Q

What conc do we see minimal effects of ethanol at

A

10mmol/L (46mg/ 100ml)

34
Q

What conc leads to severe intoxication

A

150mg/ 100ml

35
Q

What conc of ethanol is lethal

A

500mg/ 100ml - respiratory failure

36
Q

1 unit

A 
8g ethanol (amount in ½ pint, 1 measure of spirit, 1 glass wine)
Strength (ABV) x volume (ml) / 1000 = units
37
Q

UK recommendation for alcohol intake

A

14 units a week for men and women

38
Q

Where does ethanol metabolic occur

A

Liver

39
Q

Ethanol absorption

A

Ethan ol is rapidly absorbed via stomach
90% of ethanol is metabolised,
5-10% is excreted unchanged in expired air and urine, basis of police breath & urine tests

40
Q

Ethanol effects on body

A 
Cardiovascular system 
Endocrine system 
GI tract 
Liver - most serious long term consequence 
Foetal development
41
Q

Ethanol effects on cardiovascular system

A

Cutaneous vasodilation, causes warm feeling but actually increases heat loss

42
Q

Ethanol effects on endocrine system

A

Diuresis – caused by inhibition of release of ADH (hormone) from the pituitary

43
Q

Ethanol effects on GI tract

A

Increased salivary and gastric excretion

44
Q

Ethanol effects on liver

A

Increased fat accumulation —> hepatitis and finally hepatic necrosis and fibrosis
Effects on lipid metabolism, platelet function & atherosclerosis

45
Q

Ethanol effects on foetal development

A

Foetal alcohol syndrome (FAS)

Alcohol-related neurodevelopmental disorder (ARND)

46
Q

Ethanol effects on CNS - acute ethanol intoxication

A

Slurred speech
Motor incoordination
Increased self confidence
Euphoria
Effect on mood can vary, loud and outgoing or morose and withdrawn
Intellectual and motor performance and sensory discrimination all show uniform impairment

47
Q

Ethanol effects of CNS - chronic ethanol intoxication

A

Irreversible neurological effects (e.g. dementia, peripheral neuropathy)
May be due to ethanol, but also its metabolites (e.g. acetaldehyde, FA esters)
Some effects are due to thiamine deficiency (Wernicke’s-Korsakoff syndrome)

48
Q

Mechanism of action of alcohol on CNS

A

Enhancement of GABA-mediated inhibition, similar to action to benzodiazepines
Effect smaller and less consistent though
Inhibits transmitter release in response to nerve terminal depolarisation by inhibiting opening of voltage dependent calcium channels in neurons

49
Q

Flumazenil

A

Benzodiazepine antagonist
Reverses central depressant effects of ethanol
Not used in alcohol dependence - side effect is to increase seizures

50
Q

What does alcohol increase the risk of

A 
CNS atrophy
Cardiomyopathy
Peptic ulcers
Pancreatitis
Liver damage
Varices
Testicular atrophy
51
Q

Tolerance

A

Decrease in pharmacological effect on repeated administration of drug – dose has to be increased to get same effect

52
Q

Dependence

A

State when drug-taking becomes compulsive (taking precedence over other needs

53
Q

Withdrawal (abstinence) syndrome

A

Adverse effects, both physical and psychological, occurring after stopping taking drug

54
Q

Craving

A

Intense desire for a drug that long outlasts the withdrawal (abstinence) syndrome

55
Q

Reward pathway

A

Mesolimbic/ mesocortical dopaminergic pathway

Activated by virtually all dependence-producing drug

56
Q

Nicotine and dopamine

A

Nicotine enhances synthesis and release of dopamine

Acts on cholinergic receptors on dopamine cell bodies in the ventral tegmental area (VTA)

57
Q

What does alcohol decreases the activity of

A

GABAergic interneurons
Alcoholics have hypofunction of mesolimbic system
Severity is dependent on amount consumed

58
Q

Mesocortical pathway

A

Starts in VTA and travels to prefrontal cortex, passes through nucleus accumbens

59
Q

Mesolimbic pathway

A

Begins in VTA and passes through nucleus accumbens and ends at hippocampus nucleus and amygdaloid

60
Q

Abstinence Syndrome in response to nicotine withdrawal

A

Increased irritability, impaired psychomotor tasks, aggressiveness, sleep disturbance
Last 2-3 weeks, although craving for cigarettes lasts much longer

61
Q

Main dopaminergic pathways

A

Mesolimbic
Mesocrtical
Nigrostriatal
Tubero-hypophyseal

62
Q

Abstinence syndrome in repose to ethanol withdrawal

A

Has 3 stages

63
Q

1st stage of absence syndrome (ethanol)

A

Main symptoms are tremor, nausea, sweating, fever & sometimes hallucinations
Lasts about 24hrs

64
Q

2nd stage of absence syndrome (ethanol)

A

Epilepsy-like seizures

65
Q

3rd stage of absence syndrome (ethanol)

A

‘Delirium tremens’ – results in confusion, agitation, aggression & more severe hallucinations
Develops over a few days

66
Q

Mechansims for treating drug dependence

A 
Substitution, to alleviate withdrawal symptoms 
Long-term substitution
Blocking response 
Aversive therapies 
Modification of cravings
67
Q

Examples of substitution to alleviate withdrawal symptoms

A

Benzodiazepines, to blunt alcohol withdrawal

68
Q

Examples of long-term substitution

A

Nicotine patches, chewing gum, spray, inhaler, lozenge

69
Q

Examples of blocking response

A

Varenicline spp antagonist for nAChR

70
Q

Examples of aversive therapies

A

Disulfiram to induce unpleasant response to alcohol

71
Q

Examples of modification of craving

A

Bupropion (antidepressant)

72
Q

Effects of smoking and drinking relating to having an operation

A

Increased risk of DVT
Withdrawal symptoms
Chest infections

MBBS - Year 1 (93 decks)

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