Respiratory Examination - Asthma, COPD + Corticosteroids Flashcards
Name 5 drugs commonly used in the treatment of lung conditions
B2 agonist Muscarinic Receptor Antagonist Methylxanthines Leukotriene Receptor Antagonists Glucocorticoids Loop diuretics (Pulmonary oedema)
Name some major B2 agonists
Short acting - Salbutamol
Long acting - Salmeterol
Mechanism of action of B2 agonists
Act on B2 receptors found on bronchial smooth muscle. The receptors are coupled to Gs Proteins, which cause an increase in cAMP and consequent decrease in intracellular [Ca2+]. This reduces the binding of Ca2+ by light myosin, causing smooth muscle dilation.
- Additionally, the decrease in intracellular Ca2+ will also and increase Ca2+ activated K+ currents, thus hyperpolarising muscle cells further and augmenting bronchodilation.
Give two ADRs of b2 agonists
Skeletal muscle tremor
Can act on cardiac B1 receptors to induce tachycardia and cardiac dysrhythmia
Give one negative drug-drug interaction of B2 agonists
Propanolol (beta blocker) reduces effects
Name a muscarinic receptor antagonist
Ipratropium Bromide
Tiotropium bromide
Mechanism of action of muscarinic receptor antagonists?
- Bind to and antagonise M3 cholinergic receptors on bronchial smooth muscle. This blocks the constricting effect of Ach and also inhibits mucus secretions.
Give an ADR of muscarinic receptor antagonist
Dry mouth
Systemic effects avoid as not well absorbed
When would you use muscarinic antagonists?
COPD and Asthma
Name two methylxanthines
Theophylline
Aminophyilline
What is the mechanism of methylxanthines?
Competitive antagonist of adenosine
What are two complications of methylxanthine use?
Cardiac dysrhymia
Seizure
What are some indications for the use of leukotriene receptor antagonists?
Mild asthma
What is the mechanism of action of leukotriene receptor antagonists?
Antagonise cysLT1 and prevent early and late responses from inflammatory cells
What are two ADRs of Leukotriene Receptor Antagonists?
Headache and gastrointestinal disturbance
Name three corticosteroids
Prednisolone
Beclometasone (inhaled)
Hydrocortisone
What are three indications for corticosteroids?
Immunosuppression
Anti-inflammatory therapy
Replacement of endogenous corticosteroids
Give a contra-indication for glucocroticoids
Systemic infection
What is the mechanism of action of glucocorticoids?
Diffuse into cytoplasm and bind receptor. Complex moves to nucleus and binds HRE, causing inducement and inhibition of transcription.
Give four of the post-transcriptional effects of glucocorticoids
- Upregulate B2 receptors in lungs
- Reduce production of acute inflammatory mediator by inhibiting arachadonic acid processing (Upreg lipocortin which inhibits phospholipase A2, no Prost and leukotrienes prod)
- Reduce number of circulating immunocompetent cells
- Decreases activity of cells involved in chronic stages of inflammation (macrophages/fibroblast)
Give three ADRs of corticosteroids, specifically inhaled
Oral candiadiasis
Suppression of HPA acis
Osteoporosis
What is the main cortiosteroid used in asthma and COPD?
Beclametasone
How must you stop corticosteroid therpay?
Slowly, to avoid HPA supression
Outline the indication for a loop diuretic
Pulmonary oedema
