Beta-adrenergic bronchodilators Flashcards

1
Q

what can airway receptors be found

A
  • airway smooth muscle

- Mucosa

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2
Q

What are 2 types of receptors

A
  • sympathetic (adrenergic)

- parasympathetic (cholinergic) receptors

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3
Q

What decrease airway calibre

A
  • ->edema
  • ->inflammation
  • ->muscle contraction
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4
Q

What is the clinical indicator for adrenergic Bronchodilators

A

Relaxation of smooth airway muscle in the presence of airflow obstruction

in these disease:
•Asthma
•Bronchitis
•Emphysema
•Cystic Fibrosis
•Bronchiectasis
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5
Q

What does SNS innervate

A

adrenal medulla using Norepinephrine

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6
Q

What is the effect of adrenergic stimulation of Beta 2 receptor in airway

A

bronchodilation

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7
Q

What does PNS innervate

A
  • Smooth airway muscle
  • Mucous glands
  • Pulmonary vasculature

uses Acetylcholine

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8
Q

What is the effect of cholinergic stimulation in these receptors

A
  • Bronchospasm

- Increased mucous production and thickness

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9
Q

What is agonists

A

stimulate receptors

“mimetics”

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10
Q

What is Antagonists

A

blocks receptors

“lytics”

***Drugs can stimulate or block SNS and PNS

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11
Q

What are the receptors of adrenergic ?

A

alpha 1(smooth muscle of peripheral blood vessels): Vasoconstriction/vasopressor effect

beta 1(heart)
Increased HR and contractile force
beta 2(airway)
Relaxation of bronchial smooth muscle
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12
Q

where are the muscarinic or cholinergic receptors

A

M3 cholinergic

  • Bronchial smooth muscle
  • Sub mucosal bronchial glands
  • Pulmonary, bronchial & peripheral blood vessels

M2 cholinergic
-Heart

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13
Q

What is the function of MAO and COMT

A

recycles/degrades norepinephrine

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14
Q

What are 2 types of beta-agonists

A

Direct Acting

Indirect Acting

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15
Q

What is the deal with Direct Acting beta-agonists

A

chemically similar to neurotransmitter NE

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16
Q

What is the deal with InDirect Acting beta-agonists

A
  1. COMT, MAO inhibitor

- ->increase NE available at synaptic cleft

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17
Q

What is the Primary messengers of SNS

A

NE

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18
Q

What is the secondary messengers of SNS

A

Second” messengers are responsible for specific cellular responses:

  • cAMP
  • bronchodilation, decreased secretions
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19
Q

What is the Primary messengers of PNS

A

cGMP

- bronchoconstriction, increased secretions, histamine release

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20
Q

what is the end action of cAMP after drug bind to beta 2 receptor

A
  • inactivates myosine light chain kinase
  • decrease intracellular Ca
  • -> lead to smooth muscle relaxation
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21
Q

how does salmeterol work

A

its hydrophilic so once it gets into the cell, it will anchors itself with the G protein, therefore increases the concentration of cAMP(cyclic AMP)–>continue bronchodilation

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22
Q

What is the result of drug binding to beta receptor

A

1 activation of G (guanine nucleotide) linked protein receptors

  1. G protein subunit attaches to enzyme adenyl cyclase & ATP to produce secondary messenger cAMP\
  2. lead to
    - -> inactivation of the enzyme kinase so no actin-myosin cross linkages
    - ->reduction in intracellular calcium
    - ->decrease histamine release and glandular secretions
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23
Q

What are some alpha 1 agonist drugs

A

Phenylephrine

Epinephrine

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24
Q

What is the effect of drug binding to alpha 1

A
  1. activation of G protein linked
  2. phospholipase C
    - ->release of intracellular calcium stores
    - ->kinase activation
    - ->resulting in vascular smooth muscle contraction (in periphery and airway)
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25
Q

What is ephedrine, pseudoephedrine?

A
  • powerful alpha 1 stimulant

- ->mild bronchodilator

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26
Q

What is the indication of phedrine, pseudoephedrine?

A

nasal decongestion

27
Q

What is the precaution of ephedrine

A
  • diabetes
  • glaucoma
  • CAD, CHF
  • urinary retention
28
Q

What is the indication of adrenergic agonist

A

alpha 1: vasoconstriction of blood vessels & upper airway passages

29
Q

What are 3 ways of administering adrenergic agonist

A

Local: salbutamol
Systemic: IV or IM

30
Q

What are the Adrenergic Agents and Formulations?

A
  1. Ultrashort acting
    - ->Epinephrine, Racemic Epinephrine
    - -> <3hrs
  2. Short acting(SABA)
    - ->Salbutamol, Metaproterenol
    - ->4-6 hrs
  3. Long Acting (LABA)
    - ->salmeterol, formoterol, vilanterol, indacaterol, olodaterol
    - ->12-24hrs
31
Q

Wht are the 3 classess Adrenergics

A
  1. Catecholamines
  2. Resorcinols
  3. Saligenins
32
Q

Which adrenergic class do sympathomimetic bronchilators belong to

A

Catecholamine

e.g. epinephrine

33
Q

how does Sympathomimetic bronchodilators trigger adrenegic effect

A
  • catecholamines

- derivatives of catecholamines that mimic epinephrine

34
Q

features of Resorcinol agents and example?

A

Modification of catecholamine molecule

e.g.
Metaproterenol / orciprenaline: Alupent®
Terbutaline: Bricanyl ®

35
Q

What are the features of saligenin agents and example

A

Modification of catecholamine molecule

Salbutamol – Ventolin®

36
Q

What is the deal with Keyhole Theory of β2 Specificity, exmaple ?

A

The larger the catecholamine side chain (key), the more β2 specific

e.g
Epinephrine
•Equal α and β

Isoproterenol
-Strong β, little α

Salbutamol, salmeterol
-β2 preferential

37
Q

What are the ultra short acting adrenegics

A

epinephrine, isoproterenol

  • non-specific adrenergic receptor stimulant
  • ->strong alpha 1 and beta 1

unsuitable for oral administration:
–>inactivate by COMT and MAO

38
Q

What is the onset, peak , duration of epinephrine, isoproterenol

A

onset: 3-5 minutes
peak: 5-20 minutes
duration: 1-3 hours

39
Q

What is the Indications of ultra short acting

A
  • acute asthma
  • laryngeal/airway edema
  • cardiac stimulation & systemic vasoconstriction
  • anaphylaxis
40
Q

contraindication for ultra short acting

A

pre-existing cardiac arrhythmias

41
Q

features of epinephrine, example ?

A

for life threatening systemic allergic reactions (anaphylaxis), include asthma

Epipen®, AllerjectTM

Potent catecholamine bronchodilator

42
Q

What the route/dose/frequency of epinephrine?

A

route:
IV, IM, subcu, ETT (instil), intra-cardiac (LV)

Dose
anaphylaxis (sc or im)
0.2-1.0 mg at 10-15 minute intervals

asthma (IV)
0.1-0.25 mg over 5-10 minutes, repeat every 5 - 15 mins

Epi-pen every 10-20 minutes for anaphylaxis

43
Q

How is Catecholamines metabolized

A
inactivated by COMT
Inactivated in gut and liver(oral/enteral adminstration isn't good)
•Heat
•Light
•Air
44
Q

What is Racemic Epinephrine and its indication

A

synthetic epinephrine

  1. control airway bleeding during bronchoscopy
  2. reduce airway swelling
45
Q

feature of SABA and example

A

metaproterenol/orciprenaline - Alupent®
terbutaline - Bricanyl®

*direct acting, B2 selectivity increased

46
Q

what is the onset, peak, duration of SABA (resorcinol, saligenin)?

A

onset: 1-5 min
peak: 30 -60mins
duration: 4 - 8 hrs

47
Q

What is the Indications: for SABA ?

A

acute bronchospasm

48
Q

What is the contraindication SABA?

A

tachy-arrhythmias

49
Q

What is the route/dose/frequency of SABA?

A

Route

Inhaled (via pMDI*, DPI**, nebulizer solution)
1-2 puffs or 0.5-1.0 mg every four hours prn

oral *syrup
10-20 mg tid to qid

50
Q

features of example of Saligenin Bronchodilators ?

A

beta 2 specific
indirect acting

e.g.
Salbutamol Ventolin
albuterol (USA) Airomir
Salbutamol HFA

51
Q

what is the onset, peak, duration of Saligenin Bronchodilators?

A
  • onset: 5-15 min. inhaled, up to 30 min for oral
  • peak: 30-60 min
  • duration: 3-6 hours
52
Q

Indication of Saligenin Bronchodilators

A

acute bronchospasm

53
Q

What is the Route/dose/frequency of Saligenin Bronchodilators?

A

Inhalation (pMDI, nebulizer sol’n, nebules), parenteral (injection/IV)
- inhaled: 1-4 puffs or 1.25-5 mg q 20min-4h

oral (syrup, tablets)
- 2-4 mg tid to qid

54
Q

Features of LABA

A

highly selective B2 agonist
lipophilic side chain allows for continual activation of beta2 receptor

**never montherapy with LABA as it can lead to asthma paradox

55
Q

drugs of LABA

A

salmeterol (Serevent)
formoterol (Oxeze®)
vilanterol (Incruse®)

56
Q

What is the indication of salmeterol

A

long term control of bronchospasm

57
Q

What is precaution for salmeterol

A
  • Not for use in asthma without appropriate steroid use

- Not for acute relief

58
Q

What is the Route/dose/frequency of salmeterol

A

inhaled (pMDI, DPI)

25mcg: 2 puffs bid
50mcg: 1 inhalation bid

59
Q

What is the indication of formoterol fumarate

A
  • long term control of break through bronchospasm
  • acute relief of bronchospasm
  • protection re: exercise
60
Q

contraindication of formoterol fumarate

A

anaphylaxis to milk protein

61
Q

What is the Route/dose/frequency of formoterol fumarate

A

inhaled (DPI)
6, 12 mcg Oxeze®
1-2 inhalations bid (and prn)

62
Q

An example of LABA and combination of ICS

A

Symbicort ® ICS+LABA

–> SMART asthma drug: single reliever and maintenance

63
Q

What is the clinical use of LABA

A

Maintenance therapy of asthma not adequately controlled by inhaled corticosteroids (ICS) and warrants initiation of Tx with LABA
COPD needing daily bronchodilator
Not recommended for rescue therapy
Not recommended for treatment of breakthrough symptoms or without ICS

64
Q

What are the Side Effects of LABA’s

A
Tremors (shakiness)
Tachycardia
Palpitations
Irritability
Insomnia