Pharmacotherapy of the Upper Airway

Question 1

State whether activation of the following receptors leads to vasodilation or constriction:

1. Muscarinic
2. Histamine
3. Bradykinin
4. Alpha 1 Adrenergic

Answer 1

1. Muscarinic: dilation
2. Histamine: dilation
3. Bradykinin: dilation
4. Alpha 1 Adrenergic: constriction

**Dilations lead to congestion and rhinorrhea

**Activation of the A1 adrenergic will override any negative dilations from other pathways

Question 2

Which pathway is targeted by allergies?

Answer 2

H1 Histaminic

Question 3

Which pathway is targeted by a cold?

Answer 3

Bradykinin

Question 4

The blocking of voltage sensitive sodium channels by 1st generation antihistamines has what effect?

Answer 4

Local anesthetic

Question 5

T/F: 2nd generation antihistamines have a greater antagonistic effect on histamine receptors

Answer 5

False

About the same (or worse), they just avoid the sedative effect on the CNS

Question 6

Which forms of rhinitis are best targeted by antihistamines? By decongestants?

Answer 6

Antihistamines: Allergic rhinitis

Decongestants: Viral rhinitis (also some allergic)

Question 7

The primary use of antihistamines is to block receptor mediated effects of endogenous histamines. These effects of histamine include all of the following EXCEPT:

A.Vasodilation

B.Hypertension

C.Bronchodilation

D.Stimulation of afferent pain neurons

E.Increased capillary permeability (edema)

F.Contraction of GI tract smooth muscle (cramping)

Answer 7

B, C

Question 8

Which of the following drugs is the most effective physiologic antagonist of histamine in smooth muscle?

A.Cetirizine

B.Epinephrine

C.Cimetidine

D.Albuterol

E.Diphenhydramine

F.Norepinephrine

Answer 8

B, D

**If someone is going into shock from histamine reaction- you give them epi

**Antihistamines, while effects are additive with epinephrine, are not sufficient alone for treatment

Question 9

What’s the difference between 1st generation/ 2nd generation antihistamines?

Answer 9

1st generation

• CNS action: prevents nausea, vomiting, insomnia (sleep aid)
• drying effect (mouth)
• Cough suppression- Na channel block

2nd generation

• Longer duration of action,
• very specific, only block H1
• don’t act on CNS (no sedation)
• no antiemetic effects
• no anticholinergic

Question 10

3. Which of the following statements concerning clinical use of antihistamines is FALSE?

A.Can be used to produce a local anesthetic-type effect

B.Drugs of choice for treatment of allergic rhinitis

C.Overuse associated with rebound congestion

D.Commonly used in treating motion sickness

E.Antimuscarinic sedative effects of diphenhydramine are utilized in OTC sleep aid products

F.More effective than pseudoephedrine for viral cold symptoms

Answer 10

C, F

Question 11

A 20-year-old woman is taking diphenhydramine for severe hay fever symptoms. Which of the following adverse effects is she most likely to report?

A.Increase in bladder tone

B.Dry mouth

C.Nervousness, anxiety

D.Nausea

E.Uterine cramps

F.Drowsiness

Answer 11

B, F

Question 12

Select the TRUE statement comparing 1st generation antihistamines (diphenhydramine / Benadryl) to 2nd generation antihistamines (loratadine / Claritin):

A. 2nd generation agents are less expensive

B. 2nd generation agents are more effective at blocking histamine receptors

C. 2nd generation agents are not effective in the OTC treatment of insomnia

D. 1st generation agents are less likely to cause sedation

E. 1st generation agents produce less antimuscarinic side effects

F. 1st generation agents are effective in the OTC treatment of insomnia

Answer 12

C, F

Question 13

What’s the difference in action between the decongestants Pseudoephedrine (Sudafed) and Phenylephrine (Sudafed PE)?

Answer 13

Psuedoephedrine: indirectly stimulates alpha1 receptor by increasing NE

Phenylephrine: direct stimulation to alpha1 receptor

Question 14

TRUE statements regarding pseudoephedrine include:

A.Effective against rhinorrhea and congestion due to allergies

B.Overuse associated with rebound congestion

C.Postural hypotension can be seen with higher doses

D.Greater decongestant efficacy than topical phenylephrine

E.More reliable oral bioavailability than phenylephrine

F.Agonist at alpha-1 adrenergic receptors

G.More effective antitussive agent than dextromethorphan

H.Increases neuronal release of NE

Answer 14

A. True

B. False (topical agents)

C. False- A1 receptor blocker (promethazine)

D. False

E. True

F. False (indirect agonist)

G. False

H. True

Question 15

What medication is used as an antitussive?

Answer 15

Dextromethorphan (in Robitussin)

• Antitussive dose: 15-30 mg via block of μ-opioid
• Drug abuse dose: > 500-1500 mg – via block of NMDA glutamate receptors

Question 16

TRUE statements regarding management of cough symptoms include:

A.Upper airway cough syndrome can be managed with loratadine and pseudoephedrine

B.Cough suppressants should always be used in conjunction with expectorants

C.An NSAID like naproxen may be of benefit in coughs due to common cold viruses

D.Codeine has greater antitussive efficacy and less dependence liability than dextromethorphan

E.Antihistamines are generally more effective as antitussives than opioid receptor agonists

Answer 16

C

Question 17

What are the guidelines for treatment of cough in adults?

Answer 17

Acute cough due to common cold

• 1st generation antihistamine/decongestant (e.g., brompheniramine / pseudoephedrine)
• Naproxen (tid x 5 days): blocks inflammation that stimulates cough afferents
• Other
  
  • Antitussives show mixed results
  • Zinc not recommended
  • 2nd generation antihistamines ineffective

Acute cough due to upper airway cough syndrome (postnasal drip)

• 1st generation antihistamine/decongestant (e.g., brompheniramine / pseudoephedrine)