Pharm--Decongestants, Cough Suppressants, & Expectorants Flashcards
Explain the cough sensors and signals
Cough receptors in airway and distal esophagus send vagus signals to cough center in cerebral cortex; efferents coordinate muscle responses
Acute cough definition
less than 3 wks
Subacute cough definition
3-8 wks
Chronic cough def
> 8 wks
Dextromethorphan MOA
Direct suppression of medulla cough center in brain
Dex Metabolism notable for
Prodrug metabolized by CYP2D6 to active metabolite
Dextromethorphan vs codeine?
Equipotent but dex isn’t opioid!
Dex side effects
Dizziness/lightheadedness, drowsiness, N/V/D, irritability, excitability, insomnia
So, CNS and GI
Dex C/I
MAOIs, anti-depressants, hepatic disease
Diphenhydramine MOA
H1 receptor antagonist that suppresses cough center directly in medulla (anticholinergic properties)
Benadryl side effects
Sleepiness, respiratory depression, blurry vision, dry mouth, urinary retention, constipation
Benadryl C/I
Prostatic hyperplasia, urinary obstruction, ASTHMA, COPD, MAOIs
Codeine MOA
Acts on mu receptors and depresses cough center in CNS directly
Codeine side effects
Constipation, sedation, histamine release, vasodilation, orthostatic hypotension, dizziness
Codeine C/I
Pregnancy, prostatic hypertrophy, sedatives, ARD, ASTHMA, COPD
Guaifenesin MOA
Increases mucosal volume and reduces viscosity
Guaifenesin AEs
dizziness, dry mouth, rash, N/V/D, stomach pain, hyperuricemia
Most nasal decongestants act in this way
Vasoconstriction to reduce congestion without affecting histamine release or other mediator levels
Nasal decongestants MOA
Alpha agonist (sympathomimetic) but constricts blood vessels throughout the body
Reduces blood supply to nose, decreasing amount in sinusoid vessels and dec edema
Pseudoephedrine MOA
Release of NE from adrenergic nerves
Phenylephrine (PE) MOA
Direct stimulation of adrenergic receptors on postsynaptic sites
PE metabolism
Rapidly metabolized in GI mucosa, liver, …
Compare metabolism of PseudoD and PE
Pseudo is only minimally metabolized, 88% excreted unchanged in 36 hrs; PE is metabolized quickly
Side effects of systemic decongestants
CV stimulation, CNS stimulation, and rebound congestion (ischemia from local vasoconstriction)
Sudafed and Suda PE C/I
Children, elderly, bradycardia, HyperT, heart block, HTN, v Tach
Oxymetazoline trade name
Afrin
Guaifenesin as expectorant MOA
At high doses, stimulates bronchial gland secretion
N-Acetyl cysteine MOA
Breaks mucus S-S bond
N-acetyl cysteine alternative indication
reverse tylenol overdose (or prevent)
Mucolytics that interrupt sulfide bridges - AEs with asthma
Bronchospasm - esp prob with ASTHMA
If used with asthma, use bronchodilator
Mucolytics that interrupt sulfide bridges - AEs
N/V, bad odor (sulfur), can’t use with antibiotics at once, inc mucus production so use SUCTION
Amiloride MOA
Na channel blocker diuretic; blocks Na reabsorption in CF and keeps mucus hydrated
Use these for dry coughs
Antitussives
Use these for productive coughs
Expectorants
