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Flashcards in Pharmacotherapy of Asthma Deck (90)
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1
Q

What 2 groups are asthma medications divided into?

A
  1. Controllers

2. Relievers

2
Q

What are relievers?

A

Short acting bronchodilators for quick relief (e.g. Salbutamol)

3
Q

What are controllers?

A

Drugs with sustained bronchodilatory and anti-inflammatory action

4
Q

When are relievers used?

A

Used when necessary during an attack (PRN dosing)

5
Q

When are controllers used?

A

Used to prevent asthma on a daily basis

6
Q

What are the 3 types of relievers used in asthma?

A
  1. Rapid acting and short acting beta-2 agonists
  2. Inhaled Ipratropium Bromide
  3. Short acting xanthine derivatives (theophylline)
7
Q

What are the 5 types of controllers used in asthma?

A
  1. Inhaled and systemic corticosteroids (usually dosed bd)
  2. Leukotriene receptor antagonists (Montelukost)
  3. Long acting beta-2 agonists (always given together with ICS)
  4. Sustained release theophyllines (longer acting)
  5. Anti-IgE
8
Q

What are the two categories of anti-asthmatic agents?

A
  1. Bronchodilators

2. Anti-inflammatory agents

9
Q

What classes of bronchodilators are used in asthma?

A
  1. Beta-2 receptor agonists (SABA, LABA)
  2. Xanthine drugs
  3. Muscarinic receptor antagonists
  4. Cysteinyl leukotriene receptor antagonists
10
Q

What are the short acting beta-2 adrenoreceptor agonists used in asthma?

A
  • Salbutamol
  • Fenoterol
  • Terbutaline
11
Q

In what form are the short acting beta-2 adrenoreceptor agonists given?

A

Inhaled

12
Q

What are the short acting beta-2 adrenoreceptor agonists used for?

A

Acute attack

13
Q

What are the long acting beta-2 adrenoreceptor agonists used in the management of asthma?

A
  • Salmeterol

- Formoterol

14
Q

What are the long acting beta-2 adrenoreceptor agonists used for?

A

Chronic asthma

e.g. at night or exercise

15
Q

In what form are the long acting beta-2 adrenoreceptor agonists given?

A

Inhaled or oral

16
Q

What is the mechanism of action of the beta-2 adrenoreceptor agonists?

A

Agonist on beta2-adrenoreceptors
- dilate bronchi
(relaxes bronchial muscle = bronchodilation)

17
Q

What are the 3 methods of administration of the beta-2 adrenoreceptor agonists?

A
  1. Inhalation
  2. IV
  3. Oral
18
Q

How can the beta-2 adrenoreceptor agonists be administered via inhalation?

A
  1. Aerosol inhaler (MDI)
  2. Spacer devices (>500mls) improve delivery
  3. Dry powder inhaler (autohalers)
  4. Nebulizer solutions
19
Q

When can the beta-2 adrenoreceptor agonists be given IV?

A

Only in acute severe asthma

20
Q

How commonly are the beta-2 adrenoreceptor agonists given orally?

A

Rarely used

  • onset of action is slower
  • increased SE
  • prolonged action
21
Q

What does SABA stand for?

A

Short acting beta-2 adrenoreceptor agonist

22
Q

What does LABA stand for?

A

Long acting beta-2 adrenoreceptor agonist

23
Q

What are the SABA agents used as?

A

Relievers

- used on “as needed” basis

24
Q

What SABA drugs are available for the management of asthma?

A
  1. Salbutamol
  2. Fenoterol
  3. Terbutaline
25
Q

What is the onset and duration of action of the SABA agents?

A

Inhaled: effect within 5-15 minutes

Duration of effect: 3-5 hours

26
Q

How are the SABA agents metabolized and excreted?

A

Metabolized in GIT and liver

Excreted in urine

27
Q

What are the two LABA agents available?

A
  1. Salmeterol

2. Formoterol

28
Q

What is the duration of action of the LABA agents?

A

Inhaled, duration of action is 8-12 hours

29
Q

What is the difference between Salmeterol and Formoterol?

A

The onset of action!

  • Salmeterol has a delayed onset of action, cannot be used “as needed” for an acute attack
  • Formoterol has almost the same onset of action as Salbutamol: can be used to relieve
30
Q

How are the LABA agents generally given?

A

Given regularly, 2 x daily with ICS

31
Q

When are LABA agents associated with an increased risk of death?

A

Increased risk of death if given without an ICS agent

32
Q

What are the adverse effects of the beta-2 adrenoreceptor agonists?

A
  1. CNS stimulation: tremor, tachycardia, cardiac dysrhythmia, nervousness, dizziness
  2. Tremor can be a problem in the elderly
  3. Hypokalemia
33
Q

What is important to consider in the management of elderly asthmatic patients?

A

Don’t use beta-2 adrenoreceptor agonists as relievers in the elderly - can cause tremor, rather use muscarinic receptor antagonists

34
Q

Which drug is a long-acting beta2 agonist?

A

Indacaterol Maleate

35
Q

What is the mechanism of action of Indacaterol Maleate?

A

Increases cyclicAMP and causes bronchodilation

- long acting beta2 agonist

36
Q

What is Indacaterol Maleate indicated for?

A

Indicated for use in COPD
BUT NOT ASTHMA
& cannot be used for an acute bronchospasm

37
Q

When should Indacaterol Maleate be used with caution?

A

Used with caution in patients with CVD, CAD, cardiac arrhythmias, hypertension, acute MI’s
= can lead to hypokalemia

38
Q

What are the adverse effects of Indacaterol Maleate?

A

Coughing, nasopharyngitis, URTIs, headaches, muscle spasms, worsening of COPD
&
Inhalation may result in PARADOXICAL BRONCHOSPASMS
- If this occurs, discontinue use of drug immediately

39
Q

What are the two Xanthine drugs?

A
  1. Theophylline

2. Aminophylline

40
Q

What is the mechanism of action of the Xanthine drugs

A
  • relaxing of smooth muscle
  • inhibition of phosphodiesterase = prevent breakdown of cAMP
  • competitive antagonism of adenosine (A1 & A2) receptors
  • mild anti-inflammatory effect: NOT CONSIDERED AN ANTI-INFLAMMATORY AGENT
41
Q

How are the Xanthine drugs given?

A
  1. Orally (sustained release), tablets, syrups
  2. IV
    - SR formulation is preferred (much more predictable kinetics - drugs have a very narrow therapeutic index)
42
Q

What is the bioavailability of Theophylline?

A

Well absorbed

43
Q

What is the half life of the Xanthine drugs?

A

Approximately 8-9 hours (varies)

  • increased in premature infants, elderly, liver disease, cardiac failure and infections
  • decreased in smokers
44
Q

How are the Xanthine drugs metabolized and excreted?

A

Metabolized by the liver cytochrome P450 system

Excreted in the urine

45
Q

Who is at greatest risk of toxicity with the Xanthine drugs?

A

Neonates, young infants and adults >55 years
= slowest clearance
- drug has a narrow therapeutic index

46
Q

What drug interactions are seen with the Xanthine drugs?

A
  1. Decreased plasma concentration by drugs inducing CYP450 enzymes: alcohol, barbiturates, rifampicin, phenytoin etc. and smoking
  2. Increased plasma concentration by drugs inhibiting CYP450 enzymes: cimetidine, erythromycin, ciprofloxacin
  3. Sympathomimetic agents: increase cardiac effects (both increase cAMP = increase HR etc.)
47
Q

What are the adverse effects of the Xanthine drugs?

A
  • CNS, CVS, increase gastric secretions (PUD), GIT effects, vasodilation & diuretic
  • Seizures (particularly at high doses)
48
Q

What contraindications are there to Aminophylline use?

A

Aminophylline is contraindicated in pophyria

49
Q

What are the muscarinic receptor antagonists?

A
  1. Ipratropium bromide

2. Tiotropium bromide

50
Q

What is the mechanism of action of the muscarinic receptor antagonists?

A
  • blocks muscarinic receptors

- causes bronchial smooth muscle relaxation and decreased mucous secretions

51
Q

How is Ipratropium Bromide administered?

A

Aerosol inhalation

- highly polar, small amount absorbed

52
Q

What is the onset and duration of action of Ipratropium Bromide?

A

Maximum effect after 30 minutes
Effect lasts for 3-5 hours
(short acting)

53
Q

What is the o duration of action of Tiotropium Bromide?

A

24 hour duration of action

longer acting

54
Q

What is important about the onset of action of Ipratropium Bromide?

A

NB for the bronchodilator reversibility test

- need to wait 30 minutes not the usual 15 before testing for reversibility

55
Q

What are the adverse effects of the muscarinic receptor antagonists?

A
  • dry mouth
  • bitter taste
  • paradoxical bronchoconstriction
  • urinary retention and constipation (less likely as not absorbed in the GIT)
56
Q

What are the Leukotriene Receptor Antagonists?

A
  1. Montelukast

2. Zafirlukast

57
Q

What are the Leukotriene Receptor Antagonists also effective for?

A
  1. Exercise induced asthma

2. Reduce acute reaction to aspirin (aspirin sensitive asthma)

58
Q

What is the mechanism of action

A
  • blocks leukotriene receptor
  • bronchodilation
  • anti-inflammatory effect
59
Q

How are the Leukotriene Receptor Antagonists administered?

A

Given orally

60
Q

How is Montelukast taken?

A

Once daily at bedtime

- duration 24 hours

61
Q

How is Zafirlukast given?

A

Twice daily, 1 hr before, 2 hrs after meals

- protein binding 99% = NB!

62
Q

How are the Leukotriene Receptor Antagonists metabolized and excreted?

A

Extensively metabolized in the liver

Excreted in the bile

63
Q

What are the adverse effects of the Leukotriene Receptor Antagonists?

A
  1. Emergence of Churg-Strauss Syndrome (rare) - idiosyncratic but extremely dangerous
  2. Hypersensitivity reactions (urticaria / angioedema)
  3. Neuropsychiatric adverse effects (nightmares / vivid dreams)
64
Q

What is Churg-Strauss Syndrome?

A

Disorder marked by blood vessel inflammation - can restrict blood flow to vital organs and tissues.
Also known as eosinophilic granulomatosis with polyangiitis
- Asthma is the most common sign of this syndrome

65
Q

What are important cautions with Zafirlukast?

A
  1. Causes inhibition of the cytochrome P450 enzymes (warfarin, erythromycin, terfenadine, theophylline)
  2. Causes elevated liver enzymes and hepatitis
66
Q

What are the main inhaled corticosteroids?

A
  • Beclomethasone
  • Budesonide
  • Fluticasone
  • Ciclesonide
    (last two are more potent)
67
Q

What are the main oral corticosteroids?

A
  • Prednisolone

- Prednisone

68
Q

What is the main IV corticosteroid?

A

Hydrocortisone

69
Q

What is significant about Ciclesonide?

A

It is a prodrug, metabolized to its active form inside the lung
- adverse effects profile therefore much less, especially local (candida)

70
Q

What are the clinical uses of the glucocorticosteroids in asthma?

A
  1. Chronic asthma: IH beclomethasone

2. Clinical condition deteriorates: rescue course of oral prednisone

71
Q

What is the mechanism of action of the corticosteroids?

A
  • bind to intracellular receptors
  • inhibition of transcription genes
  • up-regulate beta-2 adrenoceptors
  • decreased microvascular permeability
  • reduce inflammation
72
Q

What is significant about the fact that the corticosteroids up-regulate beta-2 adrenoceptors?

A

It makes the combination of long acting Beta2 agonists and glucocorticosteroids work well

73
Q

What is significant about the fact that the corticosteroids decrease microvascular permeability?

A

Only drugs which do this

= prevents mucous plugging

74
Q

How are glucocorticosteroids most commonly administered?

A

Inhalation via MD or DP inhaler

- use spacer devices to prevent adverse effects - wash regularly

75
Q

What can be done to prevent the adverse effect of oral candida when using corticosteroids?

A
  1. Use a spacer

2. Wash mouth out afterwards

76
Q

How much of the inhaled glucocorticosteroid is deposited in the lungs?

A

10-15%
- rest in oropharynx or GIT, highly metabolized by the liver therefore very little ends up in systemic circulation (in high enough doses possible that it can however)

77
Q

How quickly is the effect of inhaled corticosteroids achieved?

A

Takes a long time to achieve full effect

78
Q

What is significant about Fluticasone?

A

It has clinical efficacy at lower doses (½)

79
Q

What are the adverse effects of the inhaled corticosteroids?

A

Oropharyngeal candidiasis

  • sore throat, croaky voice (spacers will reduce this)
  • regular high doses = adrenal suppression
80
Q

Local adverse effects have a lower incidence with which inhaled corticosteroid and why?

A

Lower incidence with Ciclesonide because it is a prodrug

81
Q

When are inhaled corticosteroids contraindicated?

A

CI: Fluticasone and HIV protease inhibitors = risk of systemic hypercortisolism

82
Q

Which two combination asthma medications are used?

A
  1. Salmeterol + Fluticasone

2. Formoterol + Budesonide

83
Q

What is the combination Salmeterol + Fluticasone used for?

A

Used only as a controller

- for chronic, persistent asthma

84
Q

What is the combination Formoterol + Budesonide used for?

A

Used both as a controller and a reliever

  • onset of action of Formeterol = Salbutamol
  • for chronic persistent asthma
85
Q

What is Omalizumab?

A

Humanized monoclonal anti-IgE antibody

86
Q

How is Omalizumab administered?

A

SC injection 1-3 x every 2-4 weeks

87
Q

What is the mechanism of action of Omalizumab?

A
  • target IgE antibody

- prevent mast cell degranulation

88
Q

What are the clinical uses of Omalizumab?

A

Effective for allergic asthma and allergic rhinitis

89
Q

What is the major downside to Omalizumab use?

A

Very expensive

90
Q

What are the adverse effects of Omalizumab?

A
  • increased chances of malignancies (NB)
  • possible induction of Churg-Strauss syndrome, nasal polyps and adrenal insufficiency
  • viral infections, upper respiratory tract infections
  • injection site reactions