resp tract drugs: asthma and COPD Flashcards
(37 cards)
SNS action
NE or Epi bind to alpha or beta adrenoreceptors (fight or flight)
- a1: blood vessels contract
- b1: increase HR and FOC
- b2: bronchi smooth muscle relax (Epi)
PNS action
Ach bind to nicotinic (skeletal muscle) or muscarinic cholinergic receptors (rest and digest)
- m: contract muscle cell of bronchi and slow HR
bronchial asthma
recurrent and reversible SOB
- tiggers: dist, viral infection, cold, smoke, exercise, pollutants
- occurs when lung airways narrow
- bronchospasms: contraction of bronchi smooth muscle
- inflammation of bronchial mucosa (edema and increased secretions)
happens bc mast cells activated by triggers release chemicals: histamine, leukotrienes, prostaglandins
- chemicals can directly cause bronchospasms and can attract immune cells = inflammation
asthma symptoms/signs
- narrowed airway (limited airflow)
- edema
- inflammation
- thickened airway wall
- mucus
- tightened bronchiole smooth muscle
- alveolar ducts open but airflow obstructed
- difficulty breathing
- wheezing
status asthmaticus
medical emergency
- prolonged asthma attack, not responding to medical therapy
COPD
1) chronic bronchitis: bronchial edema/hypersecretions
2) emphysema (alveolar destruction- barrel chest, SA for gas exchange reduced
- progressive condition
- can have exacerbations
- main cause smoking
types of respiratory tract drugs
1) bronchodilators
2) anti inflammatory drugs
bronchodilators types
- b2 adrenergic agonists (salbutamol)
- anticholinergics (ipratropium bromide)
- xanthine derivatives (theophylline/aminophylline)
anti inflammatory drug types
- glucocorticoids (budesonide, fluticasone, combination therapy - advair diskus)
- leukotriene modifiers (montelukast)
bronchodilators (b agonists)
- sympathomimetic bronchodilators
- acts like epi that bind to b2 to relax smooth muscle in bronchi
- short acting b agonists (SABA)
- long acting b agonists
used more for asthma than COPD
selective b2 drugs
activate airway smooth muscle b2 adrenergic receptors
- salbutamol (SABA - quick relief of asthma symptoms when needed, prophylactic before exercise or a known attack)
- salmeterol (LABA)
- formoterol (LABA)
b agonists mechanism of action
dilation of airways by activating smooth muscle b2 receptors
- relax bronchial smooth muscle (dilation)
- increase airflow
b agonist indications
used for relief of bronchospasm related to asthma, COPD, and other pulmonary diseases (symptomatic relief)
- treatment of acute attacks
- prevent attacks: chronic management, exercise-induced (not used every day to control, only for specific cases like exercise)
b agonists adverse effects
- cardiac stimulation/tachycardia: may bind to b1 receptors and increase HR and FOC (could be problematic in pt with underlying heart problem, heart working harder and increase angina attack)
- tremors: acting on b receptors in skeletal muscles, less likely to maintain solid contraction of muscles
- restlessness, insomnia, anxiety (CNS stimulation): beta receptors on neurons in brain
most common in salbutamol
- more likely when given PO bc whole body exposed to drug
b agonists nursing implications
- avoid triggers
- adequate fluid intake (thinner mucus, easier to clear)
- monitor for therapeutic effects (decreased dyspnea, decreased wheezing, restlessness, and anxiety, increased respirations and quality, improved activity tolerance)
anticholinergics mechanism of action
more common in COPD than asthma
- antagonist
- against muscarinic receptors on bronchial smooth muscle
- Ach causes constriction of bronchial smooth muscle and anticholinergic drug blocks this action so airways relax and open up
anticholinergic example
ipratropium
- prevent bronchoconstriction (fixed schedule use for maintenance)
- not used alone for acute exacerbations (not fast enough)
- inhaled drug (local effect)
anticholinergic adverse effects
- dry mouth/throat (cough): molecules stay in mouth and effect PNS nerves to lower salivary secretion
- systemic effects minimal (doesn’t absorb in other areas)
methylxanthines example
- theophylline (PO)
- aminophylline (IV)
asthma treatment
methylxanthines mechanism of action
not clear how it works
- increased cell cAMP
- anti inflammatory
- adenosine receptor antagonist
causes bronchial smooth muscle relaxations, quick relief of bronchospasm for greater airflow in and out of lungs
xanthine derivatives indications
-mild to moderate cases of acute asthma
- adjunct agent in management of COPD
methylxanthines adverse effects
- CNS stimulation: anxiety, insomnia, seizures (uncontrolled AP in brain neurons)
- CV stimulation: palpitations (increased FOC/fast HR), sinus tachycardia, ventricular dysrhythmias, diuresis (increased blood flow to kidneys) this is problematic in preexisting heart problems
- GI distress: N & V
similar effects to caffeine - stimulant
methylxanthines interactions
- increased effects of theophylline with ciprofloxacin which inhibits CYP metabolism
- large amounts of caffeine can intensify adverse effects
- decreased effects of theophylline with liver enzyme inducers (antiseizure drugs) which increase metabolism
methylxanthines care implications
encourage reporting: palpitations, N&V, weakness, dizziness, chest pain, convulsions
