Medications for Respiratory Diseases Flashcards
Drugs given by inhalation
=Bronchodilators (open up airways!)
a. beta2-agonist
- short-acting (SABA)
- long-acting (LABA)
b. muscarinic antagonists
- short-acting (SAMA)
- long-acting (LAMA)
c. inhaled corticosteroids (ICS)
d. various combos of the above
Aerosol
mixture of particles suspended in a gas
- inhalation devices produce medication aerosol with particle size in ‘respirable range’
Advantages and Disadvantages of Inhalers
Advantages:
- drug delivered directly to site of action
- minimal systemic effects
- rapid relief of acute attacks
- portable, durable devices
Disadvantages:
- technique may be difficult for some
- poor technique causes reduced efficacy and increased side effects
Metered Dose Inhalers (MDIs)
= pressurized canisters of drug and propellant
~ 10% of dose reaches lungs, (~20% with spacer)
a. ‘press and breathe’, requires hand-lung coordination
b. shake prior to use
c. reduced efficacy if canister is cold
MDI Technique
- sit/stand with back straight
- shake inhaler, breathe out normally
- wrap lips around mouthpiece, take a slow deep breath in, press on inhaler while breathing in slowly
- hold breath between 5-10 seconds
- breathe out normally
* wait one minute if need second puff - rinse mouth to cut down on side effects: thrush (yeast infection causing white coating) or sore throat (from ICS)
Dry Powder Inhalers (DPIs)
= breath-activated, easier to use (less hand-lung coordination), multi-dose device
~20%..better drug delivery than MDI
powder may be pre-loaded in device or may require loading of separate dry powder capsule
**biggest problem: inadequate inspiratory flow rate
additives may cause cough and irritation
Turbuhaler (DPI) Technique
- holding Turbuhaler upright, turn coloured wheel one way and back until it clicks to load a new dose
- breathe out normally
- put mouthpiece between lips and tilt head back slightly
- breathe in deeply and forcefully
- hold breath for 10 seconds
- remove Turbuhaler and breathe out
* repeat if need another dose - if contains corticosteroid, rinse with water and spit out
Respimats
= ‘press and breathe’ multi-dose, no propellant (works like handheld nebulizer), requires less hand-lung coordination and little inspiratory effort
up to 50% drug delivery to lungs
generates smaller particle size to increase lung delivery and reduce deposition in mouth and throat
**drawback: expensive, not many drugs available in this format, device must be assembled and primed
Nebulization
= nebulizer converts drug solution into a mists which is inhaled via face mask or mouthpiece
~10% of dose delivered to lower airways
takes longer to deliver compared to MDI or DPI
Advantages and Disadvantages of Nebulization
Advantages:
- requires less coordination, good for acute attacks, anxious patients
Disadvantages:
- higher dose than MDI or DPI»_space; more side effects
- more expensive
- care/maintenance required
- not portable
Nurse’s Role in proper inhaler use
a. assess for potential barriers
- patient impairment
- side effect
- device issue
- coordination (especially in elderly)
b. assess patient technique and provide detailed instruction
Relievers (bronchodilators for intermittent symptoms)
for PRN use only
a. short-acting beta2 agonists
b. anticholinergic (less often)
Controllers (maintenance therapy)
for prevention on a fixed schedule
a. anti-inflammatory medications
- inhaled and oral corticosteroids (reduce inflammation and immune system activity)
- LTRAs, anti-allergic agents
b. bronchodialtors
- long-acting beta2 agonist
- theophylline
- anticholinergics (rarely)
Adrenocortical Steroid Hormones
“corticosteroids”
- Glucocorticoids
- regulate carbohydrate metabolism (blood sugar), regulate body’s response to stress
* cortisol is most important - Mineralocortcoids
- regulate electrolyte, salt wand water balance (blood pressure)
* aldosterone is most important - Androgens
Effects of Corticosteroids
Low dose/levels produce physiologic effect
High dose/levels produce pharmacologic effects - treat asthma
a. carbohydrate, fat and protein metabolism, glucose production and storage
b. cardiovascular
- increase blood pressure from Na+/H2O retention, increase RNB, Hgb, WBC
c. CNS
- excitation, insomnia, euphoria, psychosis
d. increase gastric acid production
e. decrease calcium absorption and increase excretion
f. immunosuppression
g. anti-inflammatory
Corticosteroids
= anti-inflammatory actions in asthma
a. decrease synthesis and release of mediators
b. decrease inflammatory cell infiltration, reduce airway edema
c. reduce bronchial hyper-reactivity, reduce mucus
d. increase b2-receptors and responsiveness to b agonists»_space; dilation
Corticosteriods in respiratory disorders
SLOW ONSET, do not relieve acute symptoms
Asthma
- prophylaxis on a fixed schedule to reduce incidence and severity of acute attacks
COPD
- acute exacerbations, chronic stable disease
Using corticosteroids in asthma
Inhaled (ICS)
- first-line therapy except for very mild cases
Onset: days, max effect in 3 months
Prototype: FLUTICASONE
Oral (OCS)
- reserved for severe asthma when symptoms cannot be controlled with other meds
- limit dose/duration of use as much as possible
Protoype: PREDNISONE
Side effects of ICS
very little systemic exposure and toxicity
Due to local deposition:
- dysphonia (difficulty speaking)
- oropharyngeal candidiasis (“thrush”, yeast infection)
- *gargle or use spacer
Long term high doses:
- bone loss in women
- adrenal insufficiency
- exacerbation of glaucoma
Side effects of OCS
notable with pharmacologic doses
Short term:
- GI intolerance, n/v, diarrhea, cramps
- glucose intolerance
- hypertension
- edema
- psychologic disturbances
- insomnia
Long term: Cushingoid features - too much cortisol
- adrenal insufficiency
- osteoporosis, avascular necrosis
- glaucoma, cataracts
- body fat redistribution (moon face, buffalo hump, truncal obesity)
- dermatologic effects (skin atrophy, purpura, telangectiasis, poor wound healing)
- stunted growth
- increased risk of infection
Adrenal insufficiency
= prolonged OCS use inhibits production of endogenous cortisol (adrenals atrophy)
- adrenal recover takes time after OCS d/c
- supplemental steroid dose in times of stress
- **patient must wear medic alert bracelet and carry emergency supply of corticosteroid
inadequate corticosteroid levels cause hypotension and hypoglycemia
unable to regulate bp, blood glucose during physiologic stress
Corticosteroids: drug interactions
ICS - few concerns
OCS
a. contraindicated in patients with certain infections
b. do not give live virus vaccine (immunosuppression)
c. caution in pregnancy, lactation
d. hypertension, diabetes, peptic ulcer disease, gastritis, osteoporosis, renal failure, infections
e. NSAIDs increase risk of GI effects
Corticosteroids: dosing and administration
ICS
a. twice daily
b. use of spacer with MDI improves delivery
c. rinse mouth after use
OCS a. once daily in AM (to decrease insomnia) b. with food (to decrease GI effects) c. physiologic dose < 5mg per day pharmacologic dose > 5mg per day
OCS withdrawal
a. TAPER SLOWLY
b. determined by degree of adrenal suppression
c. taper not required for acute dosing of less than 14 days
withdrawal symptoms if tapered too quickly
- hypotension, hypoglycemia, myalgia, arthralgia, fatigue
Beta2-agonist
= activate b2-adrenergic receptors in lung smooth muscle causing #bronchodilation
Route: inhalation, oral or parenteral
Indications:
- asthma reliever and controller medication
- prevention of asthma exercise-induced bronchospasm
- chronic stable COPD and acute COPD exacerbation
Inhaled Short-Acting Beta2 Agonist (SABA)
= relief of acute asthma attacks, prevention of exercise-induced symptoms
Onset: QUICK, within 1 minute
Dose: PRN basis, not for regular use
Prototype: SALBUTAMOL (blue coloured MDI)
Inhaled Long-Acting Beta2 Agonist (LABA)
= sustained relaxation of airways and prolonged symptom relief (good for nocturnal symptoms)
= asthma controller medication, chronic stable COPD
Onset: delayed, 10-30mins
Dose: q12hr
Prototype: SALMETEROL
Oral Beta2 Agonists
Prototype: SALBUTAMOL
- slow and erratic absorption
- will not relieve acute asthma attacks
- more side effects (in circulatory)
- longer acting than inhalation
- regular use, not PRN
- not commonly used
Parenteral Beta2 Agonists
- *asthmatic emergencies
- unable to use inhaled therapy, coughing excessively, poor response to nebulization/MDI, life-threatening cases
a. Salbutamol
b. epineprhine (non-selective beta agonist)
- SC most often (also IM or IV)
- increased side effects
Beta2 Agonist: side effects
a. can stimulate beta 1 receptors in heart
- increase HR, contractility, angina, arrhythmias
b. stimulate beta2 in skeletal muscles
- tremor, anxiety, restlessness
c. increase blood glucose (glycogenolysis in liver)
d. hypokalemia
*side effects decreases with continued use
Salbutamol Dosing and Route of Administration
MDI inhalation: 100-200 mcg
Nebulization solution: 2.5mg
Oral tablet: 2mg
Injection: 4-8mcg/kg
Beta2 Agonist Warning (Overuse)
- frequency of use is a marker for asthma control
- SABA > 3x per week need anti-inflammatory medication
- SABA several times daily require urgent re-assessment
increased morbidity and mortality with over use
- masking of serious underlying inflammation
- increased airway responsiveness to triggers
Combination ICS and LABA
Advair (FLUTICASONE + SALMETEROL)
- maintenance controller therapy for moderate to severe asthma
Frequency: use regularly, q12h
Route: MDI or DPI
Symbicort (BUDESONIDE + FORMOTEROL)
‘Single inhaler therapy’
- reliever and controller
- or controller alone (formoterol is both SABA and LABA)
- only approved for patients 12 years or older
Leukotriene Receptor Antagonists (LTRAs)
= block leukotriene receptors
(leukotriene normally causes bronchoconstriction, eosinophil infiltration, mucous production and airway edema)
Onset: days
Dose: once daily, PO only; 2 hours before exercise
asthma controller medication
- add on ICS+LABA or if unable to use ICS
- exercise-induced bronchospasm
Prototype: MONTELUKAST (Singulair)
LTRAs side effects
well tolerated, but may cause headache or nausea
*phenytoin may decrease montelukast levels
Theophylline (Uniphyl)
= bronchodilation via inhibition of phosphodiesterase and increase cAMP
- good for patients with nocturnal symptoms
- third line agent due to safety and toxicity
NARROW THERAPEUTIC INDEX»_space; TDM to titre
Dose: once or twice daily with food
- PO or IV, no inhalation
- sustained release product more stable
Indications:
- asthma controller medication
- chronic stable COPD
Theophylline: side effects and drug interactions
a. GI effects n/v, diarrhea b. CNS insomnia, restlessness, convulsions c. cardiac effects increase HR, arrhythmias
Drug Interactions:
- caffeine increases theophylline levels which causes addictive CNS and cardiac effects
- CYP450 inducers reduce levels
- CYP450 inhibitors increase levels
Muscarinic Antagonists (Anti-cholinergics)
= bronchodilation due to blockade of muscarinic cholinergic receptors
- SAMA (reliever) or LAMA (controller)
Route: inhalation only
Indications
- first line therapy in COPD
- asthma, less common off label use
Short-Acting Muscarinic Antagonists (SAMA)
= reliever medication for allergen or exercised-induced asthma, acute asthma attacks (emergency management)
- second line, less effect than SABA but can be combined with SABA
Onset: within 1 minute
Dose: q6h, PRN
Route: MDI, nebulizer
***Main use: bronchodilation in COPD
Prototype: IPRATROPIUM BROMIDE (Atrovent)
Combination SABA and SAMA
Combivent Respimat
IPRATROPIUM + SALBUTAMOL)
Long-Acting Muscarinic Antagonists (LAMA)
= mostly for bronchodilation in COPD - role in asthma unclear, may add on as controller if other agents ineffective Onset: 30 mins Dose: once daily Route: DPI using HandiHaler'
Prototype: TIOTROPIUM BROMIDE (Spiriva)
Muscarinic Antagonists: side effects
a. dry mouth
b. oropharyngeal irritation
c. metallic taste
- no systemic absorption with inhalation
- avoid getting spray in eyes: exacerbates glaucoma and dilates pupils
Key Principles for Asthma Management
a. ICS is first-line therapy for all ages
b. additional therapy added to ICS if control not achieved
c. avoid precipitating factors (allergens) and triggering medications (ASA, NSAIDs)
d. smoking cessation
e. penumococcal and annual flu vaccines
f. patient education**
Emergency Management of Asthma
Goals: relieve airway obstruction, hypoxemia, normalize lung function
a. O2 for hypoxemia
b. primary therapy: repetitive inhalation of high dose SABA via MDI/nebulizer
c. systemic corticosteroids (PO or IV) in ER
d. discontinue OCS for 5-10 days
e. increase dose ICS maintenance
Chronic Obstructive Pulmonary Disease (COPD)
= chronic bronchitis and emphysema
- important clinical difference from asthma!!
- disease course..progressive worsening
Major features:
a. chronic airway limitation
b. chronic cough, increased sputum, dyspnea, impaired gas exchange
Biggest risk factor: smoking
Acute exacerbation of COPD (AECOPD)
a. increased respiratory symptoms
- dyspnea, sputum volume, purulence
b. non-specific symptoms
- malaise, sleep disturbance, fatigue, depression, confusion
c. triggers
- inhaled irritants, allergens, GERD, CHF, drug reactions
d. 50% due to viral or bacterial infection
e. most patients get 2-3 AE per year
Goals of COPD therapy
COPD
a. slow progression
b. control symptoms
c. improve exercise tolerance
d. improve exacerbation
e. improve QoL
f. reduce mortality
AECOD
a. relief of acute symptoms
b. treat infection
c. prevent mortality
Management of COPD
a. SMOKING CESSATION
b. avoid occupational and air pollutant
c. pulmonary rehab exercise
d. immunization to respiratory infection (influenza, pneumococcal)
e. pharmacotherapy
Pharmacotherapy of Chronic Stable COPD
- SAMA and/or SABA PRN
- LAMA and/or LABA
- Theophylline
- ICS
- Phosphodiesterase-4 inhibitors may reduce AE
*add on drugs for more symptom control as disease severity increases
Role of ICS in COPD
- severe airflow limitation
- symptomatic despite max bronchodilators and theophylline
- more than 2 AE per year or needing hospitalization
- few patients benefit from maintenance corticosteroid
- ICS monotherapy not recommended
Pharmacotherapy of AECOPD
- Inhaled bronchodilators for dyspnea
SABA with or without SAMA - Oral corticosteroids (prednisone, 40mg daily x 5 days)
- antibiotics (selected cases)
- O2 (target sat 88-92%)
- No role for LABA, ICS, theophylline, PDE-4
*** don’t start but don’t stop
Antibiotics for AECOPD
= use if increased dyspnea, sputum volume and purulence, or mechanical ventilation
Most common pathogens:
H. influenza, Haemophilus species, M. catarrhalis, Strep. pneumoniae
Common antibiotic choices:
a. amoxicillin
b. 2nd or 3rd generation cephalosporin
c. respiratory fluoroquinolone
d. macrolide
