Resp Drugs

Question 1

MOA of Short-acting beta agonists

When is it used?

Common names:

Answer 1

MOA:
Directly relax bronchial smooth muscles by increasing intracellular cAMP → activates protein kinase → phosphorylation of myosin light-chain kinase → inhibition of muscle contraction

Used: Acute asthma attacks and prevention of exercise induced asthma
COPD symptomatic relief

Common Names:
Salbutamol, albuterol, terbutaline

Question 2

LABA
MOA
Uses
Examples

Answer 2

Directly relax bronchial smooth muscles by increasing intracellular cAMP → activates protein kinase → phosphorylation of myosin light-chain kinase → inhibition of muscle contraction

Uses: Asthma management, usually combined with other drugs (last 12-24 hours)

Names:
Salmeterol, formoterol, indacaterol

Question 3

SAMA

MOA
Uses
Names

Answer 3

MOA:
Relaxes bronchoconstriction caused by parasympathetic stimulation, Inhibits the mucous secretion and increases ciliary clearance. No effect on inflammatory phase
Antagonises all muscarinic receptors (M1-M5) manly M3 is relevant for bronchial smooth muscle

Uses:
Maintenance in COPD and Severe asthma
Severe acute asthma

Names:
Ipraropium (Atravent)

Question 4

LAMA
MOA
Uses
Names:

Answer 4

Binds to all M receptors, but dissociates from M1 and M3 more slowly than then M2. Has a 10 fold greater affinity for M receptors than the SAMAs

Asthma management, often combined; l
Half life is 5-6 days (once a day inhalation dose)

Tiotropium and glycopyrronium bromide

Question 5

Methylxanthines

MOA
Uses
Common Names

Answer 5

Phosphodiesterase inhibitor, increases concentrations of cAMP-> promotes catecholamine stimulation of liplysis , glycogenesis which then induces release of epinephrine from adrenal medulla (smooth muscle relaxation, anti-inflammatory)
Increased diaphragm contraction

Asthma- only in severe acute- NOT first line
COPD- second line if SABA not working

Theophylline, Aminophylline

Question 6

Corticosteroids in Asthma

MOA
Uses
NAmes

Answer 6

Bind to Cytosolic Glucocorticoid receptor- complex then then diffuses into the cell nucleus and binds Glucocorticoid response elements –inhibits IL4 and IL5 that recruit eosinophils. Prevents generation of PGE2 and PGI and leukotrienes (Sontag says it inhibits phospholipase A2)
Upregulates B2 receptors and reduces mediator release from eosinophils
Promotes eosinophil apoptosis and decrease vascular leakage

Prevention of exacerbation in asthma- improved lung function, decreased hyper-responsiveness and fewer attacks
Mainly in acute exacerbations for COPD (short course usually but at times used in maintenance)

Inhaled: Fluticasone
Oral: Predisolone- acute and chronic severe asthma (associated steroid side effects)

Question 7

Leukotriene receptor antagonists

MOA
Uses
Common Names

Answer 7

Competitively inhibits cysteinyl-leukotriene receptor type 1- antagonises contraction from leukotrienes,
Mainly symptom preventer but can also bronchodilate

Maintenance in Moderate to severe asthma. Can prevent aspirin induced asthma

Singulair

Question 8

Cromones
MOA:
Uses
Common names

Answer 8

Not understood- Prevents histamine release from mast cell
? prevents response of sensory C fibres to irritants and inhibit release of T cell Cytokines

Preventers/controller - Asthma

Cromoglycate
Nedocromil

Question 9

OMalizumab
MOA
Uses
Common Names

Answer 9

Class: anti-IgE therapy
Recombinant humanised monoclonal antibody directed against IgE- IgE bound to Omalizumab cannot bind to mast cells and stimulate allergic release
Not an acute bronchodilator
Xolair

Question 10

N-Acetylcysteine MOA

Answer 10

Opens disulphide linkages in the mucous through its free sulfhydryl group thereby lowering mucous viscosity
Restores hepatic Glutathione enhancing conjugation of acetaminophen