resp tract drugs: asthma and COPD Flashcards
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
anti inflammatory drugs: glucocorticoids general info
taken daily to deal with symptoms (not acute relief)
- many drugs in this group
- similar action to cortisol
- high doses are immunosuppressive
- steroid drug with structure based on cholesterol
- anti inflammatory
- inhaled: for chronic asthma and COPD
- inhaled form reduces systemic effects
- may take several weeks for full therapeutic effect
glucocorticoids mechanism of action
many mechanisms:
- reduce inflammatory mediators (pgs, lts, etc)
- decrease production of cytokines
- reduce infiltration and activity of inflammatory cells (eosinophils and other leukocytes)
- reduces edema (capillary permeability)
inhaled glucocorticoid examples
- budesonide
- beclomethasone
- mometasone
- fluticasone
combination preparations
- glucocorticoid +LABA
- budesonide + formoterol
- fluticasone + salmeterol (advair diskus)
- mometasone + formoterol
inhaled glucocorticoids indications
prophylaxis treatment of asthma and COPD (with LABA)
- preventative
- taken everyday
- control symptoms
inhaled glucocorticoids adverse effects
- oral fungal infections (dampen immune response in mouth)
- pharyngeal irritation
- coughing
- dry mouth
high adverse effects when not inhaled - immunosuppressant
care implications inhaled glucocorticoids
- avoid if candida in sputum
- may slow growth in children but doesn’t reduce adult height
- possible bone loss
- use b agonist inhaler before glucocorticoid
- rinse mouth to avoid fungal infection
anti inflammatory drugs: leukotriene modulators
for asthma
- all given PO
what are leukotrienes
released in immune response in asthma
cause:
- inflammation
- bronchoconstriction
- mucus production
- leukocyte recruitment
- coughing, wheezing, SOB
what do leukotriene modulators do?
suppress leukotriene effects:
- suppress smooth muscle contraction of bronchiole
- decrease mucus
- prevent vascular permeability
- decrease neutrophil and other leukocyte infiltration to the lungs, preventing inflammation
- relieving asthma symptoms
leukotriene modulator examples
leukotriene receptor antagonists:
- montelukast (generally well tolerated)
- zafirlukast (liver injury and CYP inhibition)
leukotriene synthesis inhibitor
- zileuton (liver injury and CYP inhibition)
leukotriene modulator indications
prophylaxis and chronic treatment of asthma in adults and children
- montelukast in children ages 2 and older
- daily management
not for acute asthma attacks
leukotriene modulators nursing implications
use on continuous schedule for chronic management of asthma (not acute)
improvement should be seen in 1 day - 1 week
