Cough Suppressants, Decongestants, Mucolytics Flashcards
What makes the sharp sound of a cough?
Forced expiratory effort against a closed glottis, causing rapid expulsive airflow when it opens.
Explain the cough reflex.
The initial stimulus for a cough is irritation of the bronchial epithelium, causing reflex bronchoconstriction. Cough receptors (specialized stretch receptors in the trachea and bronchial tree) send VAGAL AFFERENT SIGNALS to the cough center in the MEDULLA.
Acute cough is defined as one lasting less than ________.
3 weeks
Subacute cough is one lasting ______ to _______ ______.
3-8 weeks.
Chronic cough is defined as one lasting longer than ___________.
8 weeks.
Name a differential diagnosis list for productive cough.
Clear = bronchitis Purulent = bacterial/fungal infection Yellow= inflammatory disorder Smelly = anaerobic infection
Name some things on a differential list for a non-productive cough.
- Viral Infection
- Bronchospasm
- Allergies
- Asthma
- Airway Obstruction (CANCER)
- GERD
Name the 3 systemic-acting antitussives.
Dextromethorphan
Diphenhydramine
Codeine
How does Dextromethorphan work?
It’s initially metabolized by CYP2D6 to its active metabolite Dextrorphan.
Then it suppresses the cough reflex by direct action on the cough center in the Medulla.
Which has higher potency? Codeine or Dextromethorphan?
Equal!
Only Dextromethorphan is non-opioid!
Side effects of Dextromethrophan.
It works on the brain, so think general OTC brain side effects.
Dizziness Irritability Drowsiness Trouble sleeping Nausea Vomit Diarrhea (the GI triad)
When is Dextromethorphan contraindicated?
- People on monoamine oxidase inhibitor antidepressants.
- Advanced respiratory insufficiency
- Hepatic disease (since it’s CYP metabolized)
- If you’re allergic.
How does Diphenhydramine work?
It’s an antihistamine –> H1 receptor antagonist, but cough repression does not happen via this receptor.
It’s an anticholinergic, therefore it suppresses the cough center of the brain.
When is Diphenhydramine used?
2nd line agent used for non-productive cough caused by irritation.
Can also use in motion sickness, insomnia, and parkinsons.
Side effects of Diphenhydramine.
It’s an anticholinergic, so think of what happens when you block the effect of the PNS. Decreased mucous secretions!!
Drowsiness Respiratory Depression Blurry vision (lose parasymp control) Dry mouth Urinary retention Constipation
When is Diphenhydramine contraindicated?
- Prostate Hypertrophy
- Urinary Obstruction
- Asthma/COPD patients with already depressed respiratory function
- People on MOnoamine Oxidase Inhibitor Antidepressants (like Dextromethorphan)
How does Codeine work?
Codeine is an opioid analgesic (pain reliever) but has anti-tussive effects related to those of morphine.
Acts on mu receptors (with lower affinity than morphine.
Depresses the cough reflex by direct action on the medulla.
10% of codeine is metabolized to morphine.
Yep. Can get addicted.
Side effects of Codeine.
Constipation Sedation Histamine release Orthostatic Hypotension Vasidilation Dizziness
What pregnancy category is Codeine?
C
Describe the topical agents for cough suppression.
- Camphor - rub on chest in a thick layer. Don’t use on nose, mouth, or by mouth.
- Lozenges- Menthol. Allow to dissolve slowly. Repeat as needed.
- Inhalants - Both Camphor and Menthol
Name the only FDA approved expectorant.
Guaifenesin.
How does Guaifenesin work?
Loosens and thins the lower respiratory tract secretions by increasing the volume and viscosity of the secretions.
WHen can you not use Guaifenesin?
If you’re allergic. That’s it. High doses produce emesis.
Define Nasal Decongestants.
Vasoconstrictive drugs that reduce nasal congestion.
Do not affect histamine release or any other allergic mediators
Commonly formulated together with antihistamines.
MOA of nasal decongestants.
Alpha-adrenergic agonists (sympathomimetics)
Stimulation constricts the blood vessels throughout the body:
- Reduced blood supply to the nose
- Decrease the amount of blood in the sinusoid vessels
- Decreases mucosal edema
Name the many routes of administration of decongestants.
Oral, Topical, Intranasal spray, Inhalants
Name the 2 oral (systemic) decongestants.
Pseudoephedrine (sudafed)
and
Phenylephrine (PE)
How do Pseudoephedrines work?
Releasing norepi from adrenergic nerves.
How does Phenylephrine work?
Stimulating adrenergic receptors on post-synaptic sites.
Which has greater bioavailability? Pseudoephedrine or Phenylephrine?
Pseudoephedrine (100% vs. 38%)
Phenylephrine is rapidly metabolized by monoamine oxidase, the liver, and other tissues.
Pseudoephedrine is metabolized via demethylation to norpseudoephedrine to a MINOR extent.
Side effects of pseudoephedrine and phenylephrine.
CV - Hypertension from increase in vascular resistance, tachycardia, palpitation, arrhythmias.
CNS - Hallucinations, vivid dreams, insomnia, anxiety
Kids are more likely to experience these.
Rhinitis medicamentosa - after a while, the vasoconstriction of the alpha 1 stimulation wears off and the b1 relaxation takes over. Rebound congestion.
In what patients are pseudoephedrine and phenylephrine contraindicated?
Kids/elderly Hyperthyroidism Bradycardia Tachycardia ANY HEART PROBLEMS
What’s the active ingredient in the nose sprays used as nasal decongestants?
Oxymetazoline or Phenylephrine.
Don’t use for more than 3-5 days
What is the preferred topical decongestant in pregnancy?
Sprays
Drops
Inhalers
Sprays
Describe the advantages/disadvantages of decongestant sprays
Good: fast onset, cheap, easy, cover a large surface area
Bad: Imprecise dosage, tips get stopped up.
Describe the advantages/disadvantages of decongestant drops.
Good: for KIDS!
Bad: Awkward to use, limited coverage, can be swallowed, easily contaminated.
When are MUCOLYTICS indicated for disease?
In diseases where there is increased mucous production.
- Cystic Fibrosis
- COPD
- Bronchiectasis
- Respiratory Infections
- TB
What is a bland aerosol and what is its purpose?
Bland aerosols are “wetting agents” that dilute the mucus molecule, essentially.
Can use sterile, distilled water, saline, hypertonic saline to increase mucus production, etc..
What’s the most commonly used mucolytic? MOA?
N-acetylcysteine.
Breaks the disulfide bonds of mucus and subs a sulfhydryl group.
How are mucolytics administered?
Aerosol or direct instillation into the endotracheal tube.
Why would you give N-acetylcysteine orally?
To reduce liver injury in NSAID (tyloenol) overdose. Mix it with coke, and it works!
Side effects of mucolytics:
Bronchospasm-If used in asthma patients, mix a bronchodilator with it.
Increased mucus pruduction - be prepared to suction a patient who can’t cough or is intubated.
Terrible smell.
Nausea/vomiting
Sodium bicarbonate is used how?
It’s another mucolytic. It increases the pH of mucus by weakening carbohydrate side chains.
What drug is a clone of deoxyribonuclease, a DNase enzyme which digests extracellular DNA?
Dornase Alfa (Pulmozyme)
reduces viscosity of secretions during an infection by breaking down the DNA of mucous.
Indications for Pulmozyme.
Cystic Fibrosis
Bronchiectasis
Will pulmozyme work on sputum that is not infected?
NOPE!
Side effects of Pulmozyme.
Voice alteration Pharyngitis/Laryngitis Rash Chest Pain Conjunctivitis
Contraindications for Pulmozyme.
WEIRD
Patients that are hypersensitive to Chinese Hampster Ovary cell products.
What is Amiloride?
A diuretic given to patients with cystic fibrosis (as an aerosol)
Na+ channel blocker.
In CHF, Cl- channels are blocked, so Na+ is absorbed into the epithelium of the lung, taking all the water from the mucus with it, leaving it dry.
Amiloride blocks this Na+ absorption, allowing the mucus to remain moist.
What is Denufosol Tetrasodium?
Enhances mucosal hydratio and mucous clearance by activating Cl- secretion and inhibiting Na+ transport.
ORPHAN DRUG/
