Pharmacology Flashcards
β2-adrenoceptors Agonists
Examples -
salbutamol (SABA)
salmetorol and formoterol (LABA)
Used to Treat -
Asthma as step 1 (SABA), step 3 (LABA), COPD
Side Effects -
fine tremor, hypotension, tachycardia
β2-adrenoceptors Agonists mechanism of action
β2 receptors are coupled with Gs proteins
Agonist binding stimulates adenylyl cyclase which converts ATP onto cAMP
Phosphodiesterase breaks down cAMP
Decreases intracellular Ca2+ levels and increases formation of protein kinase A
Protein kinase A phosphorylates myosin light chain kinase, which brings about relaxation of bronchi smooth muscle
Cysteinyl Leukotriene Receptor (CysLT1) Antagonists
Examples -
montelukast, zafirlukast
Used to Treat -
asthma as step 4, rhinitis
Side Effects -
headaches
abdominal pain
Cysteinyl Leukotriene Receptor (CysLT1) Antagonists mechanism of action
CysLT are derived from mast cells
- Mast cells produced arachidonic acid by stimulation of phospholipase A2
- Stimulation of 5-lopoxygenase by FLAP enzyme
- Release of leukotrienes which bind to CysLT1
Cause muscle contraction, mucus secretion and oedema
Antagonists prevent binding or leukotrienes
Xanthines
Examples -
Theophylline, Aminophylline
Used to Treat -
asthma
Side Effects -
nausea, vomiting, abdominal discomfort, headache
Xanthines mechanism of action
Inhibit phosphodiesterase, which increases cAMP levels (breakdown of cAMP is inhibited)
Decreases protein kinase A
Corticosteroids
Examples -
beclometasone (inhaled), prednisolone (oral)
Used to Treat -
asthma (mild or moderate), oral is used to treat severe, rhinitis
Side Effects - Oropharyngeal candidiasis (thrush) Dysphonia (hoarse and weak voice) Growth restrictions Glaucoma Diabetes Cushing’s syndrome
Corticosteroid mode of action
Signalling via nuclear receptors GRα, where glucocorticoid binds to GRα and enters the nucleus.
Binds to promotor region and either produces transactivation or transrepression of genes
1) Gene induction: annexin-1
- Annexin-1 inhibits synthesis of phospholipase A1
- Decreases formation of arachidonic acid and decreases production of leukotrienes, chemotaxins and spasmogens
2) Gene repression: cytokines
- Decreases formation of IL4, 5, 7 & 13
- Eosinophils and plasma cells (IgE) are not recruited
Cromlins
Examples -
cromoglicate
Used to Treat -
allergic asthma, allergic rhinitis
Side Effects -
local irritation
cromlins mode of action
Decreases sensitivity of expose C-fibres in endothelium
Muscarinic Ach Antagonists of M3 Receptors
Examples -
ipratropium, which is non selective (SABA)
tiotropium, which is selective for M3 receptors (LABA)
Used to Treat -
COPD (in combo inhalers), rhinitis (as it decreases watery secretions)
Side Effects - Dry mouth Dizziness Oropharyngeal candidiasis Taste disturbance
Muscarinic Ach Antagonists of M3 Receptors mechanism of action
Prevents the binding of an agonists and the following response:
- Activated M3 acts on Gq coupled protein
- Increases formation of phospholipase C
- Pip2 degrades phospholipase C into IP3
- Calcium is released
- Smooth muscle of bronchi contracts
Omalizumab
Used to Treat -
allergic asthma
Side Effects -
abdominal pain, pyrexia
Omalizumab mode of action
Monoclonal antibody treatment against IgE
H1 Receptor Antagonists
Examples -
anti histamines e.g loratadine
Used to Treat -
Allergic rhinitis
Side Effects -
Drowsiness
Palpitations
Hypotension
