Mucokinetics

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Mucokinetics

• RC 195

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Mucokinetics drugs that increase and aid
clearance of respiratory tract secretions

• Hypoviscosity agents (Wetting agents)
• Mucolytics
• Expectorants (Bronchomucotropics)

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Muco-ciliary Blanket

• 95 water, 2 glycoproteins
• Gel layer-high viscosity from goblet cells
• Sol layer low viscosity from submucosal
  bronchial glands

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Both goblet cells and bronchial sub-mucosal
glands increase secretion when irritated. Vagal
stimulation will also increase bronchial
sub-mucosal gland secretion.

• Increased goblet cell secretion increased
  sputum viscosity.
• Increased bronchial sub-mucosal gland secretion
  decreased sputum viscosity

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Mucokinetics are needed when secretions

• increase in amount and/or viscosity

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Hypoviscosity/Wetting Agents Water

• Systemic administration, eg P.O. or IV, decreases
  viscosity by increasing the sol layer
• Aerosol may decrease viscosity by diluting the
  gel layer
• Limitations of aerosol
• Nebulizer output
• Bronchospasm
• Hypotonicity and mucosal swelling

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Hypoviscosity/Wetting AgentsSaline solutions

• Normal Saline (.9)
• Isotonic and good diluent for drugs
• Half-normal Saline (.45)
• Hypotonic, good diluent, and can be administered
  via USN
• Aerosol solutions tend to increase in tonicity as
  they go deeper into the lung because of
  evaporation!

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Hypoviscosity/Wetting AgentsSaline solutions
(cont.)

• Hypertonic Saline (usually 10)
• Wetting agent
• Bronchorrhea (draws fluid from mucosa to dilute
  gel)
• May also help break up mucoprotein-DNA bonds in
  mucus (mucolytic effect!)
• Limitations
• Bronchospasm
• Hypernatremia

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Hypoviscosity/Wetting AgentsSodium Bicarb

• Usually 2 7.5 solution
• Wetting agent and bronchorrhea
• Also alkaline pH breaks up hydrogen bonds
• Also breaks up calcium bonds
• Like hypertonic saline, it is both a wetting
  agent and a mucolytic
• Can usually NOT be used as a diluent for drugs
• Has same side effects as hypertonic saline

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Mucolytics

• Aid mucokinesis by breaking up bonds in mucus

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MucolyticsMucomyst (N-Acetylcysteine)

• 10 or 20 solution (hypertonic and alkaline pH)
• Breaks disulfide bonds (most effective form of
  mucolysis)
• Also breaks mucoprotein bonds and hydrogen bonds
• Bronchorrhea

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MucolyticsMucomyst (N-Acetylcysteine) cont.

• Aerosol dose is 2-5ml of 10
• 10 is as effective as 20 when aerosolized and
  is not as irritating
• Side effects/Pre-cautions
• Bronchospasm
• May need a concurrent bronchodilator
• Decreased ciliary activity
• Patient may need to be suctioned if he cant
  cough effectively
• Nausea/rhinorrhea

• Reacts with metal and rubber
• Shelf life is 96 hours after opening
• Should be refrigerated
• Purple streaks when too old
• Inactivates some antibiotics if they are
  aerosolized with Mucomyst

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MucolyticsPulmozyme (Dornase Alpha or DNAse)

• Excellent aerosol mucolytic for cystic fibrosis
  patients
• Lyses the DNA bonds in the sputum of cystic
  fibrosis patients
• These patients have a lot of these bonds!

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Expectorants (Bronchomucotropics)

• Usually stimulate sol layer production by direct
  irritation or indirect through vagal stimulation
• Remember, increased sol means decreased
  viscosity!
• Smoke is a bronchomucotropic!
• Unfortunately, its irritation stimulates the
  bronchial submcosal glands AND the goblet cells
  so mucus production increases as well as
  viscosity
• Spicy food causes increased sol due to vagal
  stimulation!

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Vagal Stimulation and Mucokinesis
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Expectorants (Bronchomucotropics)SSKI

• Vagal stimulation and irritation when
  administered orally
• Also stimulates proteolytic enzymes for a slight
  mucolytic effect
• Side effects/Precautions
• Tastes like hell!
• Excess vagal stimulation
• N V, diarrhea, bradycardia
• Anaphylaxis

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Expectorants (Bronchomucotropics)Guaifenesin

• Vagal stimulation like SSKI but not as foul
  tasting or severe side effects
• Active ingredient in many cough medicines, eg
  Robitussin
• Prescription version is Humibid (pills)
• Guaifenesin is a very effective expectorant for
  chronic bronchitis

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Expectorants (Bronchomucotropics)Ammonium
Chloride

• Vagal stimulation only
• Found in many childrens cough syrups because
  it is easy to flavor
• Side effects are like SSKI and Guaifenesin
• Also may cause metabolic acidosis

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One more case study!
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This is the end of this course. But.
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