COPD and Asthma

Question 1

B2 adrenergic receptor agonist

Answer 1

Short acting - Salbutamol, terbutaline
Long acting - Salmetrolol and lomoterol

Long acting B2 receptor agonists are analogues of SABA with long lipophilic chains allowing the active drug to remain @ the site for longer

Question 2

MOA B2 agonists

Answer 2

Acts on B2 adrenorecptors in SM of upper airways. They stimulate adenylate cyclase enzymes to increase production of CAMP the ensuing cascade leads to K+ channels hyperpolarising the sarcolemma and reduced Ca2+ intracellularly therefore SM relaxation

Question 3

Indications

Answer 3

Acute severe asthma. COPD, hyperkalemia

Question 4

SE of B2 agonists

Answer 4

Fine tremor, palpitations, headaches and anxiety
Lactic acidosis, hypokalemia if used in high doses

Side effect risk increase if given systemically

Question 5

Administration of B2 agonists

Answer 5

Nebuliser 5mg for acute severe asthma

Inhaled via spacer for asthma - education of inhaler technique is crucial to ensure correct dose. If >3x weekly use further treatment required

Question 6

Use in obstetrics

Answer 6

Salbutamol/terbutaline can be used to delay uncomplicated pre-mature labour by 48hrs. Inhibiton of uterine contractions can give time to administer steroids and aid lung maturation

Question 7

Muscarinic antagonists

Answer 7

SAMA - ipatropium , LAMA - tiatropium

Question 8

MOA muscarinic antagonists

Answer 8

Competitive antagonists at the M3 receptor on bronchial SM and mucus glands. They bind to the receptor site changing its shape preventing ach binding. This leads to SM relaxation and reduced mucus secretion

Question 9

CI B2 agonists

Answer 9

IHD, HTN

Question 10

Indications muscarinic antagonists

Answer 10

COPD - tiatropium

Asthma - ipatropium (only if B2 CI due to IHD or HTN)

Question 11

SE of muscarinic antagonists

Answer 11

Normal anticholingeric SE - blurry vision, urinary retention, constipation, dry eyes

Close angle glaucoma, AF and palpitations

Question 12

Methylxanthine

Answer 12

Theophylline

Question 13

MOA theophylline

Answer 13

Inhibit phosphodiesterase isoenzymes resulting in increased cAMP levels and SM relaxation = bronchodilation. Prevent leukotriene synthesis

Question 14

SE methylxanthines

Answer 14

Acts as a nonselective adenosine antagonist hence can give tachycardia, arrhythmias and palpitations

Headaches, insomnia, hypokalemia and seziures

Question 15

Indications methylxanthines

Answer 15

IV amiophylline - acute severe asthma.

Chronic asthma esp children, COPD

Question 16

Cautions theophylline

Answer 16

Porphyria and when coadministered with epinephrine

Metabolised by CYP450 enzymes therapeutic levels can be altered by inducers and inhibitors

Question 17

Theophylline toxicity

Answer 17

PC = vomiting, agitation, cardiac arrhythmia and seizures

When given IV ensure continuous cardiac monitoring and regular K+ levels. Hypokalemia potentiated by B2 agonists

Question 18

CYP450 inducers

Answer 18

Chronic alcohol, carbamazepine, rifampicin, lamotrigine

Question 19

CYP450 inhibitors

Answer 19

Macrolides, quinolones, PPI, CCB and antifungals

Question 20

Leukotriene receptor antagonist

Answer 20

Montelukast

Question 21

MOA Montelukast

Answer 21

Act to block the leukotriene receptor. Leukotrienes are pro-inflammatory eicosanoids released from mast cells.

Inhibiting leukotrienes prevents mucus secretion and bronconstriction. Not effective in acute scenarios.

Question 22

SE montelukast

Answer 22

abdo pain, GI upset, headache
depression, suicidal thoughts
?EGPA link

Question 23

Corticosteriods

Answer 23

Prednisone, methylprednisolne, hydrocortisone and dexamethasone

Question 24

MOA corticosteriods

Answer 24

Acts as agonists to mimic action of endogenous cortisol. Once bound to the glucocorticoid cytosolic receptor, exposes the DNA binding domain. This leads to the steroid-receptor complex binding to promoter regions of target genes

Question 25

Action of cortisol

Answer 25

Inhibit bone and collagen formation Stimulate gluconeogensis Activates antiinflammatory molecules, inhibits IL-12, TNFa Counteracts insulin = increase glucose in blood Retains h20 and Na+

Question 26

Indications for steriods

Answer 26

``` AI and vasculitic conditions Cerebral oedema MSCC Addison's disease Acute severe asthma/COPD Analphylaxis Rheumatoid ```

Question 27

SE of steriods

Answer 27

``` Striae, hirsutism, acne, thin skin and easy bruising Central obesity, proximal myopathy HTN, DM Cataracts Cushings syndrome Osteoporosis (short stature in children) Psychosis and insomnia Immunosuppression - infections, candida ```

Question 28

Stopping steriods

Answer 28

Never stop steroids abruptly, due to exogenous supply of cortisol the adrenal glands can atrophy leading to deficiency of cortisol and an adrenal crisis

Question 29

Interactions with steriods

Answer 29

Antihypertensives = increased risk of hypotension NSAID's = increased risk of PUD and GI bleed High risk of hypokalemia with theophylline, B2 agonists

Question 30

Omalizumab

Answer 30

IgE monoclonal Ab used for people with severely resistant asthma >4 courses of oral steroids a year. Binds to free IgE and IgE on the surface of B lymphocytes

Question 31

Asthma PC

Answer 31

Episodic symptoms of SOB, wheeze and chest tightness. Diurnal variation worse @ morning and night, FHx of atopy, Inv - spirometry shows >15% post bronchodilator reversibility. Skin prick tests and high IgE levels

Question 32

Drug that exacerbate asthama

Answer 32

i) B-blockers = increased risk of bronchospasm ii) NSAIDs = Block prostaglandin synthesis so reflex increase in leukotriene production which increased bronchoconstriction

Question 33

Acute asthma Mx

Answer 33

High flow 02 stat. IV 100mg hydrocortisone Nebulised 5mg salbutamol (Can give back to back) If deterioration call ITU, IV Mg2SO4 Repeat PEF 15-30mins post treatment to gauge improvement

Question 34

BTS Asthma algorithm

Answer 34

Step 0 = No formal diagnosis SABA i.e. salbutamol PRN 3x weekly Step 1 = SABA and ICS Step 2 = + LABA (Given as combination inhaler) Step 3 = i) No response to LABA stop and increase ICS ii) Continue LABA +/- increase ICS Consider trial of LAMA, leukotriene or theophylline Step 4 = Increase ICS to high dose, add 4th drug Step 5 = Oral steroids at lowest dose possible SABA should be given for all steps. If using more than 3x weekly symptoms aren't controlled

Question 35

COPD PC

Answer 35

Chronic progressive dysponea, sputum prodcution, recused exercise tolerance. 40+y/o linked to smoking or pollution Goals of treatment = smoking cessation, symptom relief, improved QoL and exercise tolerance. reduced mortality, exacerbation and progression

Question 36

Algorithm for COPD

Answer 36

SAMA/SABA for all - FEV1 >50% LABA or LAMA - FEV1 <50% LAMA or LABA + ICS LAMA, LABA and ICS proven to reduce exacerbation, hospital admissions and improve exercise tolerance. Pul rehab and smoking cessation crucial

Question 37

O2 therapy in COPD

Answer 37

In COPD loss of hypercapnic drive. This in normal physiology causes pt to breathe. In COPD pt breathe relying on hypoxic drive, hence if high flow o2 is administered they may hyperventilate leading to T2RF Therefore target sats 88-92%. Monitor regularly with ABG, give O2 via targeted venturi mask. If pH < 7.35 or CO2>6 consider NIV and notify ITU

Question 38

Paediatric asthma Mx

Answer 38

Step 1 = SABA Step 2 = ICS/montelukast Step 3 = Consider adding montelukast refer to specialist

Question 39

Complete control of Asthma

Answer 39

No nocturnal symptoms, no attacks or need for rescue medication, no exercise limitation, normal lung function PEF >80% predicted

Question 40

Bad sign in acute asthma

Answer 40

paC02 climbing or in normal range = alarm bells, pt tiring and going into T2RF

Question 41

When to call ICU in acute asthma

Answer 41

Poor resp effort, falling PEF, persistent hypoxia, hypercapnia, low GCS,

Question 42

Moderate asthma attack

Answer 42

PEF 50-75% predicted, Increased symptoms

Question 43

Acute severe asthma attack

Answer 43

HR >110bpm, RR > 25, Inability to complete sentences in one breath, PEF 33-50%

Question 44

Life threatening asthma attack

Answer 44

PEF <33%, Unable to speak, O2 sats <92%, normal/high CO2, poor respiratory effort, reduced GCS, hypotension

Question 45

On discharge after asthma attack

Answer 45

Treatment with oral/inhaled steroids and bronchodilators GP follow up with 2 days, clinic within 4 weeks PEFR >75% best and when they can manage at night without nebulisers