Pharm - Asthma
Terms
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- S&S of asthma
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- SOB
- chest tightness
- wheezing
- dyspnea
- cough - common allergens
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- pollen
- smoke
- animal dander
- house dust (mites)
- feathers
- foods (shellfish, peanuts) - Some triggers of asthma
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- inhalation of allergens/pollutants
- infection
- cold air
- vigorous exercise
- emotional stress - Non-pharm ways to control asthma
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- regulate humidity (preferably above 50%)
- dry clothes in dryer
- avoid carpets
- encase mattress/pillowcase
- regularly change air exchanger/air conditioner filters
- avoid pets
- stay indoors on high pollen days - Benefits of inhaled asthma medication?
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- drugs are delivered directly to site of action
- systemic effects are minimized
- rapid onset of action - What are the most common methods of inhalation meds for asthma?
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1. Metered dose inhalers
2. Dry powder inhaler
3. Nebulizers - Metered dose inhalers
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- small handheld devices
- wait 1 min between puffs (allows time for dilation; 2nd dose penetrates deeper)
- pressurized devices
- measured doses
- inhale prior to activating device
- only 10% of drug reaches lungs (use spacers) - Dry Power Inhalers
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- easy to use
- no hand-lung coordination involved
- delivers more drug to lungs (20%)
- breath activated
- delivers drugs in the form of dry, micronized powder (directly to lungs)
- no propellants used - Nebulizers
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- small machine
- converts drugs solution into a mist
- finer particles that are easily absorbed
- used via face mask or mouthpiece
- takes minutes longer to administer same dose - Define what is meant by "selectivity is only relative, not absolute"
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beta receptors are located thoughout the body:
- beta 1: heart, vessels
- beta 2: lung
- beta 2: adrenergic agonist (non-selective) have higher intrinsic affinity for beta 2 receptors than beta 1
OTHER EFFECTS therefore: vasoconstriction, increased HR, increased FOC - What type of glucocorticoids should children take?
- - inhaled glucocorticoids (only oral when all else fails for children with asthma)
- Mild intermittent asthma
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- symptoms less than 2 times per week
- typically asymptomatic
- no daily meds needed
- preferred PRN meds: beta-2 agonist (short acting inhaled) - Mild persistent asthma
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- symptoms more than 2 times per week but less than once per day
- may affect activity
- long term control: glucocorticoids (low dose inhaled)
- PRN: beta-2 agonists (inhaled) - Moderate Persistant asthma
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- daily S&S
- exacerbations more than twice per week & affects activity level
- daily use: beta-2 agonists (short acting inhaled)
- long term control needed: beta-2 agonist ) long acting & glucocorticoids (low dose inhaled) - severe persistant asthma
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- continual S&S
- limited physical activity
- frequent exacerbations
- long term control: glucocorticoids (high dose inhaled) & beta-2 agonist (long acting) - Asthma
- chronic immune-mediated inflammatory disorder of the airway (caused by allergen)
- Allergen
- substance that can produce a hypersensitive reaction in the body but not necessarily intrinsically harmful
- Asthma Attack MOA
-
- Allergen binds to mast cells which is IgE mediated and release Histamine (causes inflammation)
- Cold/Exercise causes mast cells to degranulate and release Histamine (causes inflammation) - Classifications of Asthma medications
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1. Beta-2 adrenergic agonists (mimics SNS functions)
2. Glucocorticoids
3. Cromolyn
4. Methylxanthines - Uses for Beta-2 Adrenergic Agonists
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- acute bronchospasm
- exercise induced bronchoconstriction
- "sympathomimetic" (act like epinephrine) - Examples of Beta-2 Adrenergic Agonists
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1. Inhaled - 2 puffs
ALBUTEROL (Ventolin) - short acting (q 4-6 hours PRN)
SALMETEROL (Serevent) - LONG acting (q 12 hours)
2. Oral
Terbutaline (Brethine) - LONG acting - MOA of Beta-2 Adrenergic Agonists
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- SELECTIVELY activates beta-2 receptors
- suppresses histamine release
- increases ciliary motility
- opposite effect on bronchial smooth muscle (dilation) than VSM (constriction) - Epinephrine MOA (adrenergic receptor agonist)
- binds to adrenergic receptors which increases Ca++ returned to SR....actin myosin cross-bridges are broken....decreased contraction of bronchial smooth muscle = smooth muscle relaxation
- Side Effects of Beta-2 Agonists
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1. Tachycardia (increased HR) - stimulation of SA node
2. Increased FOC
3. Vasoconstriction
4. ANGINA (increased O2 demand in pt with CAD)
5. Tremors, sweating, agitation - What is the purpose of a spacer?
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- decreases the disposition of med in oropharynx
(wait 1 minute between puffs)
*Route: PO (long acting effects)
Inhalation (short acting effects) - Methylxanthines
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Ex. THEOPHYLLINE (Theodur)
- ORALLY (not active via inhalation)
- SR form (longer duration)
- used for CHRONIC asthma
- primarily MAINTENANCE therapy - Effects of Theophylline (Methylxanthines)
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- CNS excitation (VASOCONSTRICTION)
- bronchodilation
- Diuresis (frequent urination) - MOA of Theophylline (Methylxanthines)
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- produces bronchodilation
- inhibits PHOSPHODIESTERASE (enzyme which increases intracellular levels of cAMP)
- inhibits ADENOSINE (which causes SM contraction) by binding to adenosine receptors --> lowers intracellular Ca++ - Why is Theophylline (Methylxanthines) more dangerous than other asthma meds?
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- NARROW therapeutic range
- metabolized by liver
- SR form (contains large amounts of drug)
- has many interactions:
Caffeine
Cigarettes
Anticonvulsants
Antibiotics - What are S&S of Theophylline Toxicity?
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- INSOMNIA (restlessness)
- N/V
- diarrhea - What are the adverse effects of Theophylline (Methylxanthine)
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- severe DYSRHYTHMIAS (ventricular fibrillation)
- CONVULSIONS
- DEATH!! - MOA of glucocorticoids
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Suppresses inflammation by:
- binding to and stabilizing mast cells
- blocking PLA (phospholipase A) - Glucocorticoids?
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Examples: Pulmicort & Flovent
- primary use: PREVENT CHRONIC asthma
- REGULAR administration (NOT PRN)
- MOST EFFECTIVE anti-asthma drugs available
- very SAFE
- LONG TERM = ADVERSE EFFECTS - What are the adverse effects of glucocorticoids?
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1. ADRENAL (kidney) SUPPRESSION
2. Peptic Ulcer Disease (PUD)
3. Oropharyngeal candidiasis
4. Dysphonia (hoarseness, difficulty speaking)
5. Infection
6. Hyperglycemia
7. Osteroporosis
9. Cataracts & Glaucoma
10. Temporarily slows children's growth
11. Fluid/Electrolyte imbalances (Na+ & H20 retention) - How does administration of glucocorticoids affect one's response to stress?
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Causes ADRENAL SUPRESSION: adrenal cortex normally produces body's glucocorticoids
- patient is given glucocorticoids for asthma (abundant supply)
- adrenal gland decreases its production (several months are required for recovery of production)
- none for the body to utilize during stress
- supplement is needed
- if not, could be fatal - Uses of Cromolyn (Intal)
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(can be used to prevent asthma attack or to help current attack)
- administer on a REGULAR basis (PRIOR to attack)
- PREVENTS asthma
- exercise induced bronchospam
- Allergic rhinitis - Cromolyn
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- SUPPRESSES INFLAMMAION (NOT a bronchodilator)
- stabilizes mast cells - Classification of Asthma
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1. mild intermittent (less than 2 times/week)
PRN: Beta-2 Agonist (short acting)
Long term: NONE
2. mild persistent (more than 2 times/week)
PRN: Beta-2 Agonist (short acting)
Long term: Glucocorticoids (low dose)
3. moderate persistent (daily)
Daily: Beta-2 Agonist (short acting)
Long term: Glucocorticoids (low dose) & Beta-2 Agonist (long acting)
4. severe persistent (continual)
PRN: none
Long term: Glucocorticoids (high dose) & Beta-2 Agonist (long acting)