Pharmacology of upper airways Flashcards
Receptors affecting bronchial smooth muscles:
list which on bronchoconstricts and which on bronchodilates
Beta-2 adrenergic receptors → bronchodilation
Histamine H1 receptors → bronchoconstriction
Leukotriene receptors → bronchoconstriction
Muscarinic receptors → bronchoconstriction
Receptors affecting secretory cells and its action
Muscarinic receptor → increased secretion
Receptors affecting blood vessels and actions
Alpha 1- adrenergic receptors → vasoconstriction
Bradykinin → vasodilation
Histamine H1 → vasodilation (bronchoconstriction)
Muscarinic → vasodilation (bronchoconstriction)
Receptors affecting cough center
Mu Opioid receptors → suppress cough reflex
Receptors affecting sensory pain afferents
Bradykinin → increase pain
Histamine H1 receptors → increase pain
(note: Bradykinin → vasodilation
Histamine H1 → vasodilation (bronchoconstriction))
name two drugs to treat an anaphylactic reaction, which one is sufficient alone, and which one is additive?
Epinephrine: physiologic antagonist
Antihistamines: additive w/ epi, but not sufficient alone
Which one has a smaller role in a VIRAL inflammatory response, bradykinin or histamine?
Histamine
- hence bradykinins effects: the pain, nasal stuffiness (bv dilation), nasal fluid hypersecretion (inc. cap. perm)
Which are the primary drugs in allergic rhinitis?
Antihistamines,
Decongestants
*note: decongestants are also the primary in viral cold infxns
Anti-inflammatory agents: Corticosteroids, Cromolyn sodium
Leukotriene antagonists
What are the categories of drugs used for viral cold infxns? Which of these are also used in COPD?
Decongestants (primary)
Antitussives
Mucolytics
Expectorants
*note: the last 3 are also used in COPD
Bronchodilators
Beta adrenergic agonist (stim beta ad receptors → bronchodilate)
Anticholinergic
Anti-Inflammatory Agents
Corticosteroids
Cromolyn sodium - prevent Histamine release
Antihistamines: where do they act?
H1 receptor antagonists/block
Which class of antihistamines are highly H1 selective (less CNS penetration)
Second generation
- they also do not have anti-emetic effects
How do you produce antiemetic effect?
block both the muscarinic cholinergic AND histamine H1 receptors at multiple sites that control vomiting
Side effects of peripheral antimuscarinic drying (block secretion) actions? Which generation are these seen most in?
blurred vision, dry mouth, urinary retention
first gen antimuscarinic
*not seen at all with second generation agents
Na+ channel blockers
- list them
- what they do
- how are they used?
Diphenhydramine (benadryl)
Promethazine
Local anesthetic agents: block Na+ channels involved in AP
(maybe also cough suppressant)
Topical
What side effect do you have to worry about for adrenergic receptor blockers?
- list one drug
Phenothiazine group
May cause orthostatic HYPOtension in susceptible indivs.
List their drug name! and duration Allegra Claratin Zyrtec Clarinex Benadryl
Allegra: Fexofenadine
- 12 hrs duration
Claratin: Loratadine
Zyrtec: cetirizine
Clarinex: desloratadine
- last 3 have slower onset but 24 hr duration
Diphenhydramine
Which two drugs have the lowest risk for teratogenicity when it comes to treating nausea/vomiting in pregnancy?
Meclizine and dimendydrinate
H1 and muscarinic rcptr blocker
What is the most sedating of the second generation agents?
Cetirizine (zyrtec)
- and even more CNS depression w/ with alcohol
Second generation antihistamines
cetirizine: zyrtec # 1 most sedating of 2nd gen (but overall low sedative effects)
Fexofenadine: allegra
Loratadine: claratin
- very low sedative effects
Topical Decongestants
- name 3 drugs
- mechanism
- Phenylephrine
- Oxymetazoline
- xylometazoline
Stimulate a-1 adrenergic receptors of vascular smooth muscle → nasal vasoconstriction (of bv dilated by histamine or inflammatory response)
*promotes drainage and improve breathing, but its fast acting and can cause rebound congestion
Topical vs oral decongestants?
Topical:
rebound congestion
short duration
works at nasal vascular bed
Oral:
no rebound congestion
longer duration
affects more than just nasal vascular beds → dizziness, nervousness, nausea, high bp, palpitations
List oral decongestants
Pseudophedrine (sudafed) - safest and most effective
Phenylephrine (sudafed PE)
Antitussives
- list the drugs
Cough suppressants
- Codeine, hydrocodone
- Dextromethorphan (in robitussin)
- Diphenhydramine (benadryl)
Most commonly used OTC cough suppressant
Dextromethorphan (in robitussin)
- opioid agonist, Antitussive
In adults, how could you treat acute cough due to common cold?
1st gen antihistamine/decongestant
Naproxen 5x day (blocks inflammation + stim cough afferents)
