Module 7: Airway Pharmacology Flashcards
Albuterol Sulfate
Proventil
Ventolin
ProAir
AccuNeb
Vospire
The course of drug action from dose to effect comprises three phrases:
Drug administration phase
Pharmacokinetic phase
Pharmacodynamic phase
Drug Administration Phase
Method by which drug is made available to body
Most common devices used to administer inhaled aerosols are:
Metered-Dose Inhaler (MDI)
Soft-Mist Inhaler (Respimat)
Small-Volume Nebulizer (SVN)
Dry-powder Inhaler (DPI)
Advantages of Inhaled Aerosols
Aerosol doses are usually smaller than doses for systemic administration
Onset of drug action is rapid (immediate onset)
Delivery is targeted to the organ requiring treatment
Systemic side effects are often fewer and less severe
Most drugs can be self-administered by the patient
Disadvantages of Inhaled Aerosols
The number of variables affecting the delivered dose
Lack of adequate knowledge of device performance
Use among patients and caregivers
Pharmacokinetic Phase
Describes time course and disposition of drug in body based on its absorption, distribution, metabolism, and elimination
Pharmacodynamic Phase
Describes the 3 mechanisms of drug action by which a drug molecule causes its effects in the body through drug receptor site interactions
Sympathetic (adrenergic) receptor stimulation
Uses norepinephrine as a neurotransmitter, similar to epinephrine
Stimulation causes bronchodilation in the lungs 🫁
Parasympathetic (cholinergic) receptor stimulation
Uses Acetylcholine as a neurotransmitter
Stimulation causes bronchoconstriction in the lungs
Agonists (stimulating agent)
EX: Benadryl (anti-histamine)
A chemical that binds to a receptor site (has affinity) and blocks another chemical from activation which causes no response (no efficacy)
Adrenergic
Drug that stimulates a receptor responding to norepinephrine or epinephrine
What causes bronchodilation of the smooth muscle of the lungs?
Stimulation of the beta-2 adrenergic receptor site causes bronchodilation of the smooth muscle of the lungs
Stimulation of the muscarinic-3 cholinergic receptor site causes?
Bronchoconstriction of the smooth muscle of the lungs
Anti-cholinergic
Drug that blocks a receptor for acetylcholine
Adrenergic Bronchodilators
This class of drug is compromised of the largest single group of drugs amount aerosolized agents used for inhalation
Indications for use
Short-acting beta-2 agonists (SABA)
Short-acting beta-2 agonists (SABA)
Treatment of acute reversible airflow obstruction
Improve flow rates for asthma, acute, and chronic bronchitis, emphysema, bronchiectasis, cystic fibrosis, and other obstructive airways states
The National Asthma Education and Prevention Programs considers SABAs as rescue bronchodilators
Long Acting Beta-2 Agonists (LABA)
For maintenance bronchodilation in patients with obstructive lung disease, commonly referred to as control drugs
Ultra Short Acting Agents
Ultra Short Acting Agents catecholamine (strong alpha 1) resulting in vasoconstriction of the bronchial blood vessels
To reduce airway swelling after extubation, during croup, or epiglottitis
To control airway bleeding during endoscopy
What are the mechanisms and effects of Adrenergic Bronchodilators?
Alpha-receptor stimulation: causes vasoconstriction and vasopressin effect
Beta-1 receptor stimulation: causes increased heart rate and heart contractility
Beta-2 receptor stimulation: relaxes bronchial smooth muscle, stimulates mucociliary activity, and has some inhibitory action on inflammatory mediator release
Most common adverse effects of adrenergic bronchodilators?
Tremors
Headache
Nervousness
Insomnia
Hypokalemia
What are the side effects seen with anticholinergic aerosol agents?
SVN, MDI, and DPI (COMMON)
-Cough, dry mouth
What is the assessment for anticholinergic bronchodilators?
Vital signs, breath sounds, and breathing pattern should be evaluated before and after treatment
Patient’s subjective response is important to evaluate
How is N-Acetyl-L-Cysteine (NAC) a.k.a (Mucomyst) delivered?
Given by aerosol or direct tracheal instillation
What are the indications for N-Acetyl-L-Cysteine (NAC) a.k.a Mucomyst?
Acute bronchitis, bronchiectasis, COPD, and also acetaminophen overdose
Why is N-Acetyl-Lystine (NAC) a.k.a Mucomyst given?
Given to reduce accumulation of excessive, viscous airway mucus secretions
What are the side effects of N-Acetyl-L-cysteine (NAC) a.k.a (Mucomyst)?
May cause bronchospasm due to irritating side effects
Prophylactic therapy is recommended to reduce the irritant effects of Mucomyst, pre-treatment administration of an adrenergic bronchodilator
What is the assessment during administration for Mucus-Controlling Agents?
Breathing pattern and rate
Monitor peak flow changes and peak expiratory flow rates (PEFR)
Patient’s reaction to the treatment
What are the side effects of N-Acetyl-L-Cysteine (NAC)?
Airway Obstruction due to rapid liquefaction of secretions
Disagreeable odor due to hydrogen sulfide
Incompatibility with certain antibiotics when administered together
What are the indications and purposes of inhaled corticosteroids? `
Orally inhaled preparations used for anti inflammatory maintenance therapy of persistent asthma and severe COPD
Mechanism of action for inhaled corticosteroids?
Full anti inflammatory effects require hours to days
Will not provide immediate relief of dyspnea from airways obstruction
Inhaled corticosteroids adverse effects?
Adrenal insufficiency
Extrapulmonary allergy
Acute asthma
HPA suppression (minimal dose suppression)
Growth retardation
Osteoporosis
What are the local adverse effects of inhaled corticosteroids?
Cough, bronchoconstricion
What are the two most common types of combined inhaled corticosteroid drugs?
Fluticasone propionate/salmeterol (Advair Diskus)
Budesonide/formoterol fumarate HFA (Symbicort)
Inhaled Tobramycin goals? (TOBI)
Intended to manage chronic infection with Pseudomonas aeruginosa in patients with cystic fibrosis
Goal is to treat/prevent early colonization, and associated with a high rate of bacterial resistance
Prevents deterioration of lung function due to recurrent infections
Both ___ and ___ are approved by the U.S Food and Drug Administration (FDA)?
IIoprost and Preprostenil
What is aerosol?
A suspension of solid or liquid particles in gas
Aerosol output?
Mass of fluid or drug contained in aerosol
Output rate is mass of aerosol generated per unit of time
How is particle size determined in aerosol output?
Depends on three factors
1. Substance being nebulizer
2.Method used to generate the aerosol
3. Environmental conditions
What does MMAD mean?
Mass median aerodynamic diameter
Partical measurements correspond to the most typical settling _____?
Behavior of an aerosol
What are the three pulmonary deposition factors?
Size of the particles
Shape and motion of the particles
Physical characteristics of the airway
Sedimentation
Represents primary mechanism for deposition of small particles (1-5 m)
Breath holding for 10 seconds on peak inspiration after inhalation of aerosol increases sedimentation and distribution of lungs
Brownian Diffusion
Primary deposition mechanism for very small particles (less than 3 m) deep within the alveoli of the lungs
Aerosol Drug Delivery Systems:
MDI
SVN
DPI
USN
Atomizers and nasal spray
Vibrating mesh nebulizer
Pressurized Metered Dose Inhalers
Pressurized canister containing prescribed drug in volatile propellant combined with surfactant and dispersing agent
How is PMDI usually prescribed?
Most commonly prescribed (preferred method) of aerosol therapy delivery in both the spontaneously breathing, and the intubated/mechanically ventilated patients
How are PMDIs convenient?
Portable, compact, and easy to use
Provides multidose convenience
Has serious limitation
What are the aerosol delivery characteristics of a PMDI?
PMDIs can produce particles in respirable range (MMAD 2-6 m)
About 80% of aerosol deposits in oropharynx
Pulmonary deposition ranges between 10% and 20% in adults and larger children
10-20% of the aerosol deposits in the Oropharynx without a spacer or the two finger technique
What is the technique for use of pMDI?
Most patients do not use proper technique
THOROUGH EDUCATION OF PATIENT CAN TAKE UP TO 30 MINUTES
What is the PROPER technique for use of the pMDI?
MDI without a space should be actuated immediately after beginning a slow inspiration with mouthpiece held 4 cm in front of open mouth
This is called the two finger technique
ALTHOUGH THE USE OF A SPACER IS RECOMMENDED
Spacer is 1st choice but the two-finger technique is convenient
Approximately 60-80% of an MDI output (spray) is propellant with only 1% being active drug (50mcg-5mg) ____
Depending on the drug formula
How can you minimize Candida (Thrush) infection when using a pMDI?
It is important to have the patient rinse their mouths and gargle or the use of a spacer when using corticosteroid administration
How to ensure proper drug delivery?
MDIs not used for two days or more shod have first dose “wasted” to clear the valve stem and also new MDIs should be primed
Warm the canister to the hand or body temperature and shake vigorously before use
Who are most likely to have difficulty using an MDI?
Patients inn acute respiratory distress, infants, and young children and the elderly.
(Due to not being cooperative)
Dry powder inhalers
Breath-actuated dosing systems
How does patient create aerosol? (DPI)
By drawing air through dose of finely milled drug powder -There is no flow-
What is the expected patients inspiratory flow rate or effort when using a DPI?
> 60 L/MIN
Does not se propellants and does not require hand-breath ____
Coordination needed for PMDIs
All DPIs are ____?
Maintenance or control drugs
Patients with adequate flow rates are recommended to use either a ___?
DPI or MDI with a spacer
What is the technique use for DPI?
Patients must generate inspiratory flow rate of at least 40-60 L/min to produce respirable power aerosol
DPIs should not be used by infants, small children, those who cannot follow instructions, and patients with severe airway obstruction
Requires cleaning in accordance with product label
What is the proper technique for Small Volume Nebulizers?
Slow inspiratory flow optimizes SVN aerosol deposition
Selection of delivery method (mask or mouthpiece) i based on patient ability, reference and comfort
Infection control issues in terms of DPIs?
Nebulizers should be cleaned and disinfected or rinsed with sterile water and air dried between uses
Assessing effectiveness of aerosol delivery
(SUBJECTIVE DATA)
Patients technique when using the device
Patients response to and compliance with the procedure
Objective measurements in terms of assessing effectiveness of aerosol therapy?
Peak flowmeter (PEFR)
Bedside Spirometry (FEV1/FVC Ratio)
