Respiratory Pharmacology Flashcards
How can respiratory physiology be manipulated pharmacology?
Treatment of inflammation, pain, infection, neoplasia
Drugs to alter- bronchial diameter, antitussives, surfactants, mucolytics, expectorants, decongestants, affect respiratory centre
How is bronchial diameter normally manipulated?
Bronchodilation (sympathetic), Bronchoconstriction (parasympathetic)
Autonomic nervous system- non-adrenergic, non-cholinergic nerves
Response to irritant receptors
How can bronchial diameter be effected pharmacologically?
Autonomic agonists/antagonists
Drugs directly on smooth muscle
What receptors stimulate sympathetic system of respiratory system and what does it cause?
B2 adrenoreceptors
Causes bronchi dilation, increased action of mucocilliary escalator, recedes release of inflammatory mediators
What stimulates the parasympathetic portion of the respiratory system and what does it cause?
Muscarinic receptors
Causes bronchoconstriction and increased mucus production
What are the effects of alpha/beta sympathetic stimulation in other parts of the body?
Alpha: Vasoconstriction Intestinal sphincter contraction Intestinal sphincter contraction Pupil dilation
Beta: Vasodilation increased HR Bronchodilation Bladder relaxation Metabolic stimulation
What respiratory drugs act directly on smooth muscle and what is their mechanism of action?
Methylxanthines
MOA- phosphodiesterase inhibitors, adenosine antagonists- increasing cAMP- affects myosin light chain kinase- relaxation
What are the side effects of methylxanthines?
Taccycardia, excitability, seizures, derangement of GI motility
When should anti-tussives be used?
If a cough is non-productive, or when patient becomes exhausted
What is the mode of action and the direct and indirect effect of antitussives ?
MOA- Opioids suppress the ill defined cough centre of the brain
Direct effect- suppress cough centre in medulla oblongata, reduction of stimulus to cough
What are examples of opioids used as antitussives and what are the side effects?
Codeine and butorphanol
Side effects- sedation, suppression of CNS, constipation
What are surfactants and what is their use?
Lipid molecules generated from bovine lung extract- administered for neonate distress syndrome in premature births
What are the effects of mucolytics?
Decrease viscosity of bronchial secretions- improves clearance- more easily moved and coughed
What are two examples of mucolytics, their modes of action, administration and side effects?
Bromhexine HCL
MOA- enhances hydrolysis of mucopolysaccharides, ineffective in presence of infection or inflammation doe to presence of protein
Oral or parenteral administration
N-acetylcyteine
MOA- breaks disulphide bonds between mucus molecules, effective in infection/inflammation
Topical administration
Side effects- bronchoconstriction and airway irritation
What do expectorants do and how and name two examples?
Thought to irritate the gastric mucosa, increasing vagal tone and therefore increase bronchial secretion
Potassium Iodide
Guaifenesin
What are decongestants used for?
Used to recuse nasal mucosa thickness to enable easier passage of air
What are examples of decongestants?
Ephedrine, pseudoephedrine, phenylephrine
Poorly tolerated in animals
What is an example of a respiratory stimulant, what is its effects?
Doxapram
Increases chemoreceptor sensitivity, RR and tidal volume
Topical or parenteral
What is the preferred method of administration for respiratory diseases?
Aerosol administration
What are 4 adrenoreceptor agonists?
Adrenaline
Noradrenaline
Ephedrine
Isoproterenol
What is the best adrenoreceptor agonists for bronchodilation?
Beta 2 agonists
What are some examples of a beta 2 agonists, how are they administered?
Terbutaline- highly selective at normal dose
Parenteral, topical or oral uptake
Albuterol- selective- oral or topical administration rapid by topical
Clenbuterol- selective, orally administered
What are the adverse effects of beta 2 agonists?
BP abnormalities
Tacycardias
Hypokalaemia
Seizures
What effect will adrenoreceptor antagonists have on the respiratory system?
Bronchocontstriction
