Drugs And The Respiratory System Flashcards
Examples of centrally mediated respiratory dysfunction ….
Premature birth
Opioid intoxication
Rest syndrome
Examples of classic lung diseases …
Asthma
COPD
Pulmonary oedema
Cystic fibrosis
What is asthma ?
Chronic inflammatory disease of the airways causing bronchospasm and dyspnea
What happens in an asthma attack ?
Smooth muscle in bronchial cell walls contract constricting airways so breathing is difficult
What are common triggers of asthma ?
Allergens, rapid changes in temp, drugs and exercise
What are the symptoms of asthma ?
Feeling of breathlessness
Tight chest
Wheezing
Cough- especially at night
How is asthma diagnosed ?
Tiffneau test and/or bronchoscopy
What drugs are used to treat asthma and how do they work ?
Beta agonists - salbutamol
Increase cAMP in smooth muscle cells
This inhibits MLCK so prevents muscle contraction
Causing bronchodilation
What are common side effect if beta agonists taken in excessive amount ?
Tachycardia
Muscle tremor
Hypokalemia
Examples of long lasting beta agonists …
Salmetrol and isoproterenol
Long term prevention of attacks
What do muscarinic receptor antagonists do ?
Bronchodilation
Bind to muscarinic receptors in airway smooth muscle preventing acetylcholine binding
Also decrease mucus secretions
Particularly good against irritant induced attacks
Examples of muscarinic antagonists..
Short acting: atropine, ipratropium bromide and oxitropium bromide
Longer acting: tiotropium bromide
When does max bronchodilation of muscarinic antagonists occur and how long do their effects last ?
Max effects after 30 mins
Short- 5 hours
Long- 15 hours
What are xanthines ?
Caffeine and theobromine
They inhibit phosphdiesterase enzymes in airway smooth muscle leading to an increase in cAMP increasing relaxation
Main clinical one: theophylline
What are the problems with using xanthines as bronchodilators and what are the adverse effects ?
Narrow therapeutic use
Nausea, cardiac arrhythmias and convulsions and drug interactions
Why are anti inflammatory drugs used in asthma ?
Prevent subsequent inflammation
What is an example of an AID used in asthma ?
Glucocorticosteriod - inhibits inflammatory cell infiltration and reduces oedema
- beclometasome and budesonide
What are the symptoms of COPD?
Excessive sputum production, chronic cough and breathlessness
What does chronic bronchitis cause ?
Alveolar hypoventilation
Hypercapnia
Hypoxia
What is associated with emphysema ?
Destructive loss of alveolar structure
Chronic impairment of gas exchange
What are the treatments for chronic bronchitis ?
Bronchodilators
Mucokinetic drugs - reduce viscosity of mucus - N-acetylsysteine and ambroxol break disulphide bonds
Antibiotics - combat any bacterial infections
What is pulmonary oedema ?
Abnormal build up of fluid within alveolar space - cough and impaired gas exchange
What are the treatments for pulmonary oedema ?
Try to reduce blood volume to improve cardiac function
Diuretics (furosemide)- increase urinary loss by inhibiting reabsorption at kidney
Cardiac glycosides(digoxin) -
Phosphdiesterase inhibitors and beta 1 agonist
What is cystic fibrosis ?
Inherited disease
Primary defect is a mutation I specific proteins essential for chloride efflux
Causes thick viscous secretions in ducted organs
Causes poor ventilation and subsequent bacteial infections
What are the aims for the drugs used to treat cystic fibrosis ?
Thining the secretions
Combating opportunistic infections
What drugs are used to treat cystic fibrosis ?
Muscarinic antagonists - reduce mucus secretions
Expectorants( glyceryl guaiacolate) - increases fluidity of secretions increasing productivity of coughing
Much lyric agents ( N-actylcycsteine) - decrease viscosity
Antibiotics
What happens when you overdose on opioids ?
Centrally mediated depression of respiration
Activated a micro receptor
Inhibits adenylage Cyclase which decrease cAMP
Causes decreased neuronal excitability
Depressing ventilation
How is opioid overdose treated ?
Naloxome- opioid receptor antagonist - removes pain relief though
Activate serotonin 4a receptor to increase adenylate Cyclase - mosapride
