Download 100807 Respiratory Pharmacology Revised 319KB Jan 14 2015

Drugs that
Affect the
Respiratory
System
P. Andrews
Chemeketa Community College
Paramedic Program
Fall 07
When do we consider respiratory
medications?
• Asthma
– Decreases pulmonary function
– May limit daily activity
– Presents with
• SOB
• Wheezing
• Coughing
Or, perhaps……
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SOB, unknown etiology
Allergic reaction
Pneumonia
Congestive heart failure
Emphysema
Others…..?
Asthma, cont.
• Has numerous components!
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Bronchoconstriction
Inflammation
Edema
Mucus hypersecretion
And others….
• Usually an allergic reaction
Categories of
respiratory
meds
• Bronchodilators
• Beta2 specific agonists
(short-acting)
• Beta2 specific agonists
(long-acting)
• Methylxanthines
• Anticholinergics
• Glucocorticoids
• Leukotriene
antagonists
• Mast-cell membrane
stabilizer
Advantages of Nebulized Meds.
• Smaller doses
• Onset Rapid
• Targeted delivery
• Less side effects
Disadvantages of Inhaled Meds
• Variables in delivery
• Usage variables
– User
– Caregiver
• Requires delivery to lungs
– Not always adequate depth of respiration
Remember This?
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Absorption
Distribution
Metabolism
Elimination
Absorption and
Distribution
• Absorption
– Ionized drugs (Ipratropium)
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Absorb poorly
Won’t distribute well to body
Mostly local effect
Used for AEROSOL
– Non-Ionized drugs (Atropine)
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Absorb well
Distribute well
Systemic Effect
Poor Aerosol Drug
Quick Review of
Receptors
– Sympathetic
• Adrenergic
– Epinephrine or Nor-epinephrine
» Primary neurotransmitters
– Parasympathetic
• Cholinergic
– Acetylcholine
» Primary neurotransmitter
Muscarinic
• A drug that stimulates Acetylcholine at
Parasympathetic nerve endings.
• When drugs refer to muscarinic or
antimuscarinic action,
– It ONLY acts on Parasympathetic sites!
Adrenergic Stimulation
• Alpha 1
– Vasoconstriction
– Increase Blood Pressure
• Beta 1
– Increase Heart Rate
– Increase Force of Heartbeat
• Beta 2
– Bronchial Smooth Muscle Dilation
Adrenergic
Bronchodilators
• Indication
– Obstructive Airway Disease
• Asthma, Bronchitis, Emphysema
• Mode of Action
– Adrenergic Receptors
• Alpha 1…vasoconstriction
• Beta 1…Increase HR
• Beta 2…Bronchodilate (Yeah!)
Adrenergic Bronchodilators
• Adverse Effects
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Dizziness,
Nausea,
Tolerance,
Hypokalemia,
Tremors
H/A
Adrenergic Bronchodilators
• Nonspecific agonists
– Epinephrine (rarely used)
• Beta2 Specific agonists – Short acting
– Albuterol (Ventolin, Proventil)
• 2.5 mg in 3 mL NS
– Metaproterenol (Alupent)
– Terbutaline (Brethine)
Bronchodilators, cont.
• Inhaled Beta2 selective (long-acting)
– Salmeterol (Serevent)
Anticholinergic Bronchodilators
• Indication
– Bronchoconstriction
– Mainly in COPD
• Mode of Action
– Competes at Muscarinic receptors
– Blocks Acetylcholine at smooth muscle
– Reduces Mucus Production
Anticholinergic Bronchodilators
• Adverse Effects
– Watch for Cholinergic side effects
– More with nebulized form than MDI
• Examples
– Atrovent (ipratropium)
• 0.5 mg in 2.5 mL NS
– Combivent (mixed w/ Albuterol)
• 0.5 mg Atrovent & 2.5 mg Albuterol in 3 ml NS)
– Atropine
• 0.5 – 1 mg in 2 – 3 mL of NS
– Robinul
• Peak effects in 1 – 2 hrs
Mucus Controlling Agents
• Indication
– Excessive , thick secretions
– As in COPD and TB
• Action
– Lower viscosity of mucus
Mucus Controlling Agents
• Side effects
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Irritation of Airway
Bronchospasm
Pharyngitis, voice change, laryngitis
Chest pain
Rash
• Considerations
– Have suction ready
– Anticipate cough
Mucus Controlling Agents
• Examples
– Mucomyst (Acetylcysteine)
• COPD, TB
• Acetaminophen OD
– Pulmozyme
• Cystic Fibrosis
– Nebulized Saline
• Simple yet effective!
Inhaled Corticosteroids
• Indications
– Asthma
– Anti-Inflammatory MAINTENANCE
– Require Hours to Act! Preventative drug
• Mode of Action
– Modifies RNA/DNA action in Cells
– Complicated Stuff
Inhaled Corticosteroids
• Adverse Effect
– Small incidence with nebulized
• Oral doses have high incidence
• Considerations
– Not valuable in Acute Care
– Watch for these in Pt Drug Lists
Corticosteroids
• Examples
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Beclovent, Vanceril
Azmacort
Aerobid
Flovent
Pulmicort
Advair®
• fluticasone (steroid) and salmeterol (bronchodialator)
Glucocorticoids
• Indications
– Prophylactic treatment of Asthma
– Hayfever
Glucocorticoids (cont)
• Mode of Action
– Lowers release of Histamine in Mast Cells
– Lowers release of Inflammatory Response
• Prevents Bronchospasm, airway inflammation
– Acts in allergic and non-allergic asthma
– Not a bronchodilator!
• Not for use in acute setting
• Controllers, not relievers
Glucocorticoids (cont)
• Adverse Effects
– Include
• H/A
• Nausea
• Diarrhea
Cromolyn sodium
• Similar to glucocorticoids
• Adverse Effects
– Only coughing or wheezing
Anti-inflammatory Agents, cont.
• Corticosteroids - Injected
– Methylprednisolone (Solu-Medrol)
• Children; 0.25 mg/kg (max dose 125 mg IVP)
• Adults; 125 mg IVP
– Dexamethasone (Decadron)
Nasal Decongestants
• Alpha1 agonist
– Phenylephrine
– Pseudoephedrine
– Phenylpropanolamine
• Administered as mist or drops
• Side Effects – rebound congestion (use
greater than 7 days)
Antihistamines
• Blocks histamine receptors
• Common 1st generation – cause sedation
– Chlor-Trimeton
– Benadryl
– Phenergan
• Common 2nd generation – does not cause sedation
– Seldane
– Claritin
– Allegra
• Caution: thickens bronchial secretions – do not
use in Asthma!
Cough Suppressants
• Antitussive meds – suppress cough stimulus
in CNS
– Codeine, hydrocodone
A couple of ‘odd’ ones
Epinephrine
Racemic Epinephrine
(microNEFRIN)
• Class
– Bronchodilator (adrenergic agonist)
• Action
– Affects both beta1 and beta2 receptors sites.
Bronchodilation, reduces subglottic edema
– Also increases pulse rate and strength
– Also Alpha effects, vasoconstriction, Increased
BP
Epinephrine
• Indications
– Croup, Epiglottitise
• Bronchospasm
• Absorption
– Absorption occurs following inhalation
• Half-life
– Unknown
Epinephrine
• Contraindications
– Hypersensitivity
• Precautions
– Watch for Rebound Worsening
– Watch ECG for changes
– Increases Myocardial O2 demand
• Side effects
– Nervousness, restlessness, tremor, arrhythmias,
hypertension, tachycardia
Epinephrine
• Interactions
– Beta blockers may negate effects
• Route and dosage
– Inhalation
• One time Only
• 1 mg Epinephrine, 1:1000 in 3 mL NS
• Considerations
– Give ENROUTE
– ONLY if patient in Extreme Distress
Epi, cont.
• May also consider Epi SQ
– Patients who can’t cope with aerosol admin.
– 0.3 – 0.5 mg SQ, then Neb treatment once
patient can move air
• Or Infusion;
– 1 mg Epinephrine 1:1000 in 250 mL NS
(concentration 4 mcg/mL) infuse at 1 mcg/min,
titrating to effect
Magnesium Sulfate
• Not usually admin. in pre-hospital setting
• Can be used to treat moderate to severe
asthma in patients who respond poorly to
beta-agonists
• Don’t use in patients with heart blocks,
myocardial damage, or hypertension
• 2 gm in 100 mL NS, given over 2 – 5 min.
Status Asthmaticus
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