Pharmacology of upper airways

Question 1

Receptors affecting bronchial smooth muscles:

list which on bronchoconstricts and which on bronchodilates

Answer 1

Beta-2 adrenergic receptors → bronchodilation

Histamine H1 receptors → bronchoconstriction
Leukotriene receptors → bronchoconstriction
Muscarinic receptors → bronchoconstriction

Question 2

Receptors affecting secretory cells and its action

Answer 2

Muscarinic receptor → increased secretion

Question 3

Receptors affecting blood vessels and actions

Answer 3

Alpha 1- adrenergic receptors → vasoconstriction

Bradykinin → vasodilation
Histamine H1 → vasodilation (bronchoconstriction)
Muscarinic → vasodilation (bronchoconstriction)

Question 4

Receptors affecting cough center

Answer 4

Mu Opioid receptors → suppress cough reflex

Question 5

Receptors affecting sensory pain afferents

Answer 5

Bradykinin → increase pain
Histamine H1 receptors → increase pain

(note: Bradykinin → vasodilation
Histamine H1 → vasodilation (bronchoconstriction))

Question 6

name two drugs to treat an anaphylactic reaction, which one is sufficient alone, and which one is additive?

Answer 6

Epinephrine: physiologic antagonist
Antihistamines: additive w/ epi, but not sufficient alone

Question 7

Which one has a smaller role in a VIRAL inflammatory response, bradykinin or histamine?

Answer 7

Histamine

• hence bradykinins effects: the pain, nasal stuffiness (bv dilation), nasal fluid hypersecretion (inc. cap. perm)

Question 8

Which are the primary drugs in allergic rhinitis?

Answer 8

Antihistamines,
Decongestants

*note: decongestants are also the primary in viral cold infxns

Anti-inflammatory agents: Corticosteroids, Cromolyn sodium
Leukotriene antagonists

Question 9

What are the categories of drugs used for viral cold infxns? Which of these are also used in COPD?

Answer 9

Decongestants (primary)
Antitussives
Mucolytics
Expectorants

*note: the last 3 are also used in COPD

Question 10

Bronchodilators

Answer 10

Beta adrenergic agonist (stim beta ad receptors → bronchodilate)

Anticholinergic

Question 11

Anti-Inflammatory Agents

Answer 11

Corticosteroids

Cromolyn sodium - prevent Histamine release

Question 12

Antihistamines: where do they act?

Answer 12

H1 receptor antagonists/block

Question 13

Which class of antihistamines are highly H1 selective (less CNS penetration)

Answer 13

Second generation

• they also do not have anti-emetic effects

Question 14

How do you produce antiemetic effect?

Answer 14

block both the muscarinic cholinergic AND histamine H1 receptors at multiple sites that control vomiting

Question 15

Side effects of peripheral antimuscarinic drying (block secretion) actions? Which generation are these seen most in?

Answer 15

blurred vision, dry mouth, urinary retention

first gen antimuscarinic

*not seen at all with second generation agents

Question 16

Na+ channel blockers

• list them
• what they do
• how are they used?

Answer 16

Diphenhydramine (benadryl)
Promethazine

Local anesthetic agents: block Na+ channels involved in AP
(maybe also cough suppressant)

Topical

Question 17

What side effect do you have to worry about for adrenergic receptor blockers?
- list one drug

Answer 17

Phenothiazine group

May cause orthostatic HYPOtension in susceptible indivs.

Question 18

List their drug name! and duration
Allegra
Claratin
Zyrtec
Clarinex
Benadryl

Answer 18

Allegra: Fexofenadine
- 12 hrs duration

Claratin: Loratadine
Zyrtec: cetirizine
Clarinex: desloratadine
- last 3 have slower onset but 24 hr duration

Diphenhydramine

Question 19

Which two drugs have the lowest risk for teratogenicity when it comes to treating nausea/vomiting in pregnancy?

Answer 19

Meclizine and dimendydrinate

H1 and muscarinic rcptr blocker

Question 20

What is the most sedating of the second generation agents?

Answer 20

Cetirizine (zyrtec)

• and even more CNS depression w/ with alcohol

Question 21

Second generation antihistamines

Answer 21

cetirizine: zyrtec # 1 most sedating of 2nd gen (but overall low sedative effects)

Fexofenadine: allegra
Loratadine: claratin
- very low sedative effects

Question 22

Topical Decongestants

• name 3 drugs
• mechanism

Answer 22

1. Phenylephrine
2. Oxymetazoline
3. 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

Question 23

Topical vs oral decongestants?

Answer 23

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

Question 24

List oral decongestants

Answer 24

Pseudophedrine (sudafed) - safest and most effective

Phenylephrine (sudafed PE)

Question 25

Antitussives

- list the drugs

Answer 25

Cough suppressants

1. Codeine, hydrocodone
2. Dextromethorphan (in robitussin)
3. Diphenhydramine (benadryl)

Question 26

Most commonly used OTC cough suppressant

Answer 26

Dextromethorphan (in robitussin)

- opioid agonist, Antitussive

Question 27

In adults, how could you treat acute cough due to common cold?

Answer 27

1st gen antihistamine/decongestant

Naproxen 5x day (blocks inflammation + stim cough afferents)