Respiratory Drugs Flashcards
Beta-2 Agonist Examples
Salbutamol
Salmeterol
Formoterol
Terbutaline
Beta-2 Agonist Indications
- Asthma
- COPD
- Hyperkalaemia
Beta-2 Agonist mechanism of action
Beta-2 receptors found in smooth muscle of bronchi, GIT, uterus and blood vessels.
Agonisation leads to smooth muscle relaxation - improves airflow.
Stimulates Na+/K+ pumps on cell surface membranes, causing K+ to move into cell
Beta-2 agonist contraindications
May cause tachycardia - caution in cardiac disease as can promote angina / arrhythmias
Beta-2 agonist side effects
Stimulates sympathetic “fight or flight response” = tachycardia, palpitations, anxiety, tremor. Promote glycolysis = increased glucose.
Long-acting can produce muscle cramps.
Beta-2 agonist interactions
Beta-blockers: efficacy reduced
Corticosteroids: hypokalaemia
Antimuscarinic examples
Tiotropium, Ipratopium
Antimuscarinic indications
- COPD: short-acting relieves SOB, long-acting prevents SOB and exacerbations.
- Asthma: short-acting adjunct during acute exacerbation, long-acting added to high-dose inhaled corticosteroids and beta-2 agonists in step 4 of treatment ladder
Antimuscarinic mechanism of action
Competitively inhibit acetylcholine at muscarinic receptor. Muscarinic receptors stimulate parasympathetic system. Receptor blockade =
- increased heart rate
- smooth muscle relaxation (bronchodilation)
- reduce glandular secretions in resp and GI tracts
- relax pupillary constrictor = dilated pupils
- relax ciliary muscles = prevents accomodation reflex
Antimuscarinincs contraindications
Caution in patients with:
- Angle-closure glaucoma: increase IOP
- Arrhythmias
Antimuscarinics side effects
Dry mouth
Antimuscarinics interactions
None as have low systemic absorption
Corticosteroids examples
Prednisolone, hydrocortisone, dexamethasone
Corticosteroids indications
- Allergic / inflammatory disorders: asthma, anaphylaxis
- Suppression of autoimmune disease: IBD, arthritis
- Cancer treatment - as part of chemo or to reduce tumour swelling
- Hormone replacement in adrenal insufficiency or hypopituartism
Coricosteroid mechanism of action
- Mostly glucocorticoid effects:
- Modify the immune response
- Up-regulate anti-inflammatory genes
- Down-regulate pro-inflammatory genes e.g. cytokines, TNF-alpha
- Suppress eosinophils and monocytes
- Increase gluconeogenesis
Some mineralocorticoid effects:
- Stimulate Na+ and water retention
- Promote K+ and H+ excretion