Flashcards in Respiratory Pharmacology Deck (16)
Describe the sympathetic innervation to the respiratory system
B2 -> bronchodilation through innervation to bronchial blood vessels and glands not bronchial smooth muscle
Increased cAMP, decreased Ca2+, reduces muscle contraction. This stimulates Ca2+ activated K+ channels -> hyperpolaristion, bronchodilation
Describe the parasympathetic innervation to the respiratory system
M3 bronchoconstriction and mucus secretion
Name two short acting B2 agonists
(Duration of action 3-5hours)
Name two long acting B2 agonists
(Duration of action 8-12hours)
What are the adverse effects of B2 agonists?
High doses inhaled can cause skeletal muscle tremor (B2 activity), they can also antagonise cardiac B1 receptors causing tachycardia and dysrhythmia, headaches, hypokalaemia
Caution in those with cardiac abnormalities
Do not give with B-blockers
Give two examples of methylxanthines
(Narrow therapeutic window)
How do methylxanthines work?
Antagonist to adenosine receptors
Inhibit the breakdown of cAMP by phospohdiesterase
Increase cAMP -> decreased calcium leading to bronchodilation
What are the adverse effects of methylxanthines?
Psychomotor agitation, tachycardia, nausea, Vomitting
Name two muscarinic receptor antagonists
Ipratropium bromide (short-acting)
Tiotropium bromide (long-acting) (Spireva)
What are the adverse effects of muscarinic receptor antagonists?
Not well absorbed though the lungs, they don't discriminate between different muscarinic receptor subtypes, dry mouth, constipation, urinary retention
Are there any considerations that need to be taken into account when prescribing IV aminophylline?
It has a narrow therapeutic window, so it needs to be carefully monitored, plasma level 10-20mg/L
What are the contraindications for the use of muscarinic receptor antagonists?
Use with caution in those with angle-closure glaucoma and BPH
Give three examples of inhaled steroids
How do they work?
Beclomethasone (Qvar), budesonide, fluticasone
They increase airway calibre by decreasing bronchial inflammation
What are the side effects of inhaled steroids?
Cough, oral thrush, unpleasant taste, hoarseness of voice
Give examples of PO/IV steroids