Resp - Pharm (H1 blockers, Expectorants, & other respiratory drugs)

Question 1

What is the mechanism of H1 blockers?

Answer 1

Reversible inhibitors of H1 histamine receptors

Question 2

What are the categories of H1 blockers? Give examples of at least 3 drugs in each category.

Answer 2

1ST GENERATION: Diphenhydramine, Dimenhydrinate, Chlorpheniramine; 2ND GENERATION: Loratadine, Fexofenadine, Desloratadine, Cetirizine

Question 3

What are 3 examples of 1st generation H1 blockers? What do their names contain?

Answer 3

(1) Diphenhydramine (2) Dimenhydrinate (3) Chlorpheniramine; Think: Name contain “-en/-ine” or “-en/-ate”

Question 4

What are 3 clinical uses of 1st generation H1 blockers?

Answer 4

(1) Allergy (2) Motion sickness (3) Sleep aid

Question 5

What are 3 toxicities associated with H1 blockers?

Answer 5

(1) Sedation (2) Antimuscarinic (3) Anti-alpha-adrenergic

Question 6

What are 4 examples of 2nd generation H1 blockers? What do their names contain?

Answer 6

(1) Loratadine (2) Fexofenadine (3) Desloratadine (4) Cetirizine; Names usually end in “-adine”

Question 7

What is the clinical use of 2nd generation H1 blockers?

Answer 7

Allergy

Question 8

What is the significance/advantage of 2nd generation H1 blockers in terms of toxicities?

Answer 8

Far less sedating than 1st generation because of decreasing entry into CNS

Question 9

What are 2 examples of Expectorants?

Answer 9

(1) Guaifensin (2) N-acetylcysteine

Question 10

What is the mechanism of Guaifenesin?

Answer 10

Expectorant - thins respiratory secretions; does not suppress cough reflex

Question 11

What is the mechanism of N-acetylcysteine? In what 2 ways is it used clinically?

Answer 11

Mucolytic - can loosen mucous plugs in CF patients. Also used as an antidote for acetaminophen overdose.

Question 12

What kind of drug is Dextromethorphan, and what is its mechanism? Of what is it an analog?

Answer 12

Antitussive (antagonizes NMDA glutamate receptors). Synthetic codeine analog.

Question 13

What effect does Dextromethorphan have when used in excess?

Answer 13

Has mild opioid effect when used in excess

Question 14

What is given for Dextromethorphan overdose?

Answer 14

Naloxone can be given for overdose

Question 15

What is a potential toxicity of Dextromethorphan?

Answer 15

Mild abuse potential

Question 16

What is the mechanism of Pseudoephedrine? What other drug shares its function/properties?

Answer 16

Sympathomimetic alpha-agonistic nonprescription nasal decongestants; Phenylephrine

Question 17

What are 4 clinical uses for Pseudoephrine and Phenylephrine?

Answer 17

Reduce (1) hyperemia, (2) edema, and (3) nasal congestion; (4) open obstructed eustachian tubes.

Question 18

How can Pseuodoephedrine be used outside of the clinic?

Answer 18

Pseudoephedrine also illicitly used to make methamphetamine

Question 19

What are 2 possible toxicities of Pseudoephedrine and/or Phenlyephrine?

Answer 19

(1) Hypertension. (2) Can also cause CNS stimulation/anxiety (pseudoephedrine).