Management Of Cough Flashcards
What is cough?
Useful physiological mechanism that serves to clear the respiratory passages of foreign material and excess secretions
What underlying causes can you look for when treating a cough
- GERD
- Infection
- Worms
-Drugs
List the 5 classes of anticough agents
- Antitussive
- Antihistamines
- Pharyngeal demulcents
- Expectorants
- Mucolytics
What is the MOA of antitussives
Inhibits cough reflex by suppressing cough center in medulla or peripheral receptors
Drugs classified as antitussives
- Codeine central acting
- Pholcodine and Noscapine
- Dextromethorphan
- Benzonatate
Disadvantages of antitussives
-Addiction
-Drowsiness
- Constipation
- Respiratory depression
Difference between codeine-central acting drugs and pholcodine
-Pholcodine is longer acting than codeine
- Do not have analgesic nor addictive properties
- Do not cause constipation
- Does not interfere with mucociliary movement
Which anticough agent should be avoided in children and asthmatics
Codeine and Pholcodine
What is the most widely used cough suppressant
Dextromethorphan
What form of administration is available for Dextromethorphan
Tablets
Syrup
Spray forms
What receptors are targeted by Dextromethorphan
NMDA receptors
What is the therapeutic use of Dextromethorphan
Temporary relief of cough caused by minor throat and bronchial irritation
What cough suppressant removes sensation
Benzonatate
Which is the drug of choice to suppress cough in patients undergoing bronchoscopy
Benzoate
What is the MOA of antihistamines
They are H1 receptor antagonists
They target histamine receptors of the smooth muscle.
List first generation H1 receptor antagonists
Diphenhydramine
Chlorpheniramine
Cyclizine
Promethazine
Cyproheptadine
Ketorifen
List second generation H1 receptor antagonists
Cetirizine
Fexofenadine
Loratadine
Desloratadine
Olopatadine
Azelastine
What are the major differences between first and second generation antihistamines
First generation Antihistamines block both histaminic and muscarinic receptors as well as passing the BBB
Second generation Antihistamines mainly block histaminic receptors and do not pass the BBB
Why are second generation antihistamines preferred over first generation
Due to their favourable efficacy/safety ratio and lack of cholinergic and sedative side effects
Half life of first generation antihistamines
4 to 12 hrs
Half life of second generation antihistamines
12 to 24 hrs
What are other therapeutic uses of antihistamines
- H1 blockers have major application in allergies of the immediate type
- Used as anti motion sickness drugs
- Morning sickness in pregnancy (Doxylamine and pyridoxine)
- Appetite stimulants
List pharyngeal demulcents
Lozenges
Linctus
Honey
Cough drops
Liquorice
What is the MOA of pharyngeal demulcents
Used when cough arises due to irritation above larynx by protecting irritant receptors in mucosa or respiratory tract
Produce soothing effect on inflamed mucosa
May contain mild local anesthetics
What is the MOA of expectorants
Increase volume of bronchial secretion
Reduce the thickness, adhesiveness, and surface tension of mucus so cough becomes less tiring and productive
What are the two classifications of expectorants
- Directly acting on RT cells ( Guaifenesin)
- Reflex acting: stimulate the RT secretions by secreting gastric mucosa
(Ammonium salt, iodides, some bitter herbs like ipecac)
What is the MOA of mucolytics
Breakdown mucus
Examples of mucolytics
Bromohexine
Acetyl cysteine
What are bland aerosols
Drugs that dilute mucus molecules and are known as wetting agents
Types of bland aerosols
- Sterile and distilled water (humectant, dense aerosols and asthmatics)
- Normal (isotonic saline)
- Hypertonic saline
- Hypotonic saline
MOA of bland aerosols
Disruption of disulfide bonds
-Acetyl cysteine breaks the bonds by substituting a sulfhydryl radical
Hazards of acetylcysteine
- Bronchospasm
- Increase mucus secretion
- Do not mix with antibiotics in the same nebuliser
- Nausea and vomiting (smells like rotten eggs)
- Alteration of pH
- Proteolysis
Common side effects of pulmozyne
- Voice alteration
- Pharyngitis/ laryngitis
- Rash
MOA and side effects of bromohexine
Liberates lysosomal enzymes which digest mucopolysaccharides, hence decrease viscosity of sputum
Side effects: rhinorrhea and lacrimation
MOA of amiloride
It is a sodium channel blocker. In cystic fibrosis, Na+ is absorbed in the epithelium along with H2O, leaving the mucus thick and dehydrated.
By blocking sodium absorption, dehydration of the mucus is prevented.
MOA of denusfosol tetrasodium
Enhances mucosal hydration and mucus clearance by activating Cl- secretion and inhibiting epithelial Na+ transport
