1. Mucokinetics
RC 195

2. Mucokinetics – drugs that increase and aid clearance of respiratory tract secretions
Hypoviscosity agents (Wetting agents)
Mucolytics
Expectorants (Bronchomucotropics)

3. Muco-ciliary Blanket 95% water, 2% glycoproteins
Gel layer-high viscosity from goblet cells
Sol layer – low viscosity from submucosal bronchial glands

4. 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

5. Mucokinetics are needed when secretions
increase in amount and/or viscosity

6. 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

7. Hypoviscosity/Wetting Agents: Saline 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!

8. Hypoviscosity/Wetting Agents: Saline 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

10. Hypoviscosity/Wetting Agents: Sodium 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

11. Aid mucokinesis by breaking up bonds in mucus
Mucolytics
Aid mucokinesis by breaking up bonds in mucus

12. Mucolytics: Mucomyst (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

13. Mucolytics: Mucomyst (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 can’t 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

14. Mucolytics: Pulmozyme (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!

15. 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, it’s 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!

16. Vagal Stimulation and Mucokinesis

17. 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

18. 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

19. Expectorants (Bronchomucotropics): Ammonium Chloride
Vagal stimulation only
Found in many children’s “cough” syrups because it is easy to flavor
Side effects are like SSKI and Guaifenesin
Also may cause metabolic acidosis

20. One more case study!

21. This is the end of this course. But….