Drugs that Affect the Respiratory System

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Drugs that Affect the Respiratory System

• P. Andrews
• Chemeketa Community College
• Paramedic Program
• Fall 07

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When do we consider respiratory medications?

• Asthma
• Decreases pulmonary function
• May limit daily activity
• Presents with
• SOB
• Wheezing
• Coughing

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Or, perhaps

• SOB, unknown etiology
• Allergic reaction
• Pneumonia
• Congestive heart failure
• Emphysema
• Others..?

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Asthma, cont.

• Has numerous components!
• Bronchoconstriction
• Inflammation
• Edema
• Mucus hypersecretion
• And others.
• Usually an allergic reaction

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Categories of respiratory meds

• Bronchodilators
• Beta2 specific agonists (short-acting)
• Beta2 specific agonists (long-acting)
• Methylxanthines

• Anticholinergics
• Glucocorticoids
• Leukotriene antagonists
• Mast-cell membrane stabilizer

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Advantages of Nebulized Meds.

• Smaller doses
• Onset Rapid
• Targeted delivery
• Less side effects

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Disadvantages of Inhaled Meds

• Variables in delivery
• Usage variables
• User
• Caregiver
• Requires delivery to lungs
• Not always adequate depth of respiration

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Remember This?

• Absorption
• Distribution
• Metabolism
• Elimination

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Absorption and Distribution

• Absorption
• Ionized drugs (Ipratropium)
• Absorb poorly
• Wont distribute well to body
• Mostly local effect
• Used for AEROSOL
• Non-Ionized drugs (Atropine)
• Absorb well
• Distribute well
• Systemic Effect
• Poor Aerosol Drug

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Quick Review of Receptors

• Sympathetic
• Adrenergic
• Epinephrine or Nor-epinephrine
• Primary neurotransmitters
• Parasympathetic
• Cholinergic
• Acetylcholine
• Primary neurotransmitter

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Muscarinic

• A drug that stimulates Acetylcholine at
  Parasympathetic nerve endings.
• When drugs refer to muscarinic or antimuscarinic
  action,
• It ONLY acts on Parasympathetic sites!

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Adrenergic Stimulation

• Alpha 1
• Vasoconstriction
• Increase Blood Pressure
• Beta 1
• Increase Heart Rate
• Increase Force of Heartbeat
• Beta 2
• Bronchial Smooth Muscle Dilation

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Adrenergic Bronchodilators

• Indication
• Obstructive Airway Disease
• Asthma, Bronchitis, Emphysema
• Mode of Action
• Adrenergic Receptors
• Alpha 1vasoconstriction
• Beta 1Increase HR
• Beta 2Bronchodilate (Yeah!)

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Adrenergic Bronchodilators

• Adverse Effects
• Dizziness,
• Nausea,
• Tolerance,
• Hypokalemia,
• Tremors
• H/A

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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)

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Bronchodilators, cont.

• Inhaled Beta2 selective (long-acting)
• Salmeterol (Serevent)

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Anticholinergic Bronchodilators

• Indication
• Bronchoconstriction
• Mainly in COPD
• Mode of Action
• Competes at Muscarinic receptors
• Blocks Acetylcholine at smooth muscle
• Reduces Mucus Production

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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

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Mucus Controlling Agents

• Indication
• Excessive , thick secretions
• As in COPD and TB
• Action
• Lower viscosity of mucus

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Mucus Controlling Agents

• Side effects
• Irritation of Airway
• Bronchospasm
• Pharyngitis, voice change, laryngitis
• Chest pain
• Rash
• Considerations
• Have suction ready
• Anticipate cough

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Mucus Controlling Agents

• Examples
• Mucomyst (Acetylcysteine)
• COPD, TB
• Acetaminophen OD
• Pulmozyme
• Cystic Fibrosis
• Nebulized Saline
• Simple yet effective!

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Inhaled Corticosteroids

• Indications
• Asthma
• Anti-Inflammatory MAINTENANCE
• Require Hours to Act! Preventative drug
• Mode of Action
• Modifies RNA/DNA action in Cells
• Complicated Stuff

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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

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Corticosteroids

• Examples
• Beclovent, Vanceril
• Azmacort
• Aerobid
• Flovent
• Pulmicort
• Advair
• fluticasone (steroid) and salmeterol
  (bronchodialator)

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Glucocorticoids

• Indications
• Prophylactic treatment of Asthma
• Hayfever

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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

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Glucocorticoids (cont)

• Adverse Effects
• Include
• H/A
• Nausea
• Diarrhea

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Cromolyn sodium

• Similar to glucocorticoids
• Adverse Effects
• Only coughing or wheezing

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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)

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Nasal Decongestants

• Alpha1 agonist
• Phenylephrine
• Pseudoephedrine
• Phenylpropanolamine
• Administered as mist or drops
• Side Effects rebound congestion (use greater
  than 7 days)

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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!

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Cough Suppressants

• Antitussive meds suppress cough stimulus in CNS
• Codeine, hydrocodone

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A couple of odd ones
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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

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Epinephrine

• Indications
• Croup, Epiglottitise
• Bronchospasm
• Absorption
• Absorption occurs following inhalation
• Half-life
• Unknown

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Epinephrine

• Contraindications
• Hypersensitivity
• Precautions
• Watch for Rebound Worsening
• Watch ECG for changes
• Increases Myocardial O2 demand
• Side effects
• Nervousness, restlessness, tremor, arrhythmias,
  hypertension, tachycardia

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Epinephrine

• Interactions
• Beta blockers may negate effects
• Route and dosage
• Inhalation
• One time Only
• 1 mg Epinephrine, 11000 in 3 mL NS
• Considerations
• Give ENROUTE
• ONLY if patient in Extreme Distress

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Epi, cont.

• May also consider Epi SQ
• Patients who cant cope with aerosol admin.
• 0.3 0.5 mg SQ, then Neb treatment once patient
  can move air
• Or Infusion
• 1 mg Epinephrine 11000 in 250 mL NS
  (concentration 4 mcg/mL) infuse at 1 mcg/min,
  titrating to effect

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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
• Dont use in patients with heart blocks,
  myocardial damage, or hypertension
• 2 gm in 100 mL NS, given over 2 5 min.

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Status Asthmaticus