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