General oto pharmacology

Question 1

Review the differences between first-generation

and second-generation antihistamines.

Answer 1

Compared with first-generation antihistamines, second-
generation medications generally have a longer duration of action, have less central nervous system (CNS) penetration,
and are less sedating.

Question 2

Review contraindications to glucocorticoid steroid

use.

Answer 2

Psychosis, severe diabetes, peptic ulcer disease, congestive
heart failure, severe hypertension, systemic tuberculosis,
osteoporosis

Question 3

Describe the features of ototoxicity associated

with salicylate use.

Answer 3

Reversible sensorineural hearing loss and tinnitus, hy-
pothesized to result from disruption of oxidative phos-
phorylation. Its use does not produce histologic changes.

Question 4

What severe neurologic side effect is associated
with intramuscular administration of
prochlorperazine?

Answer 4

Extrapyramidal side effects including focal dystonia

Question 5

List the different amide and ester local anesthetics.

Answer 5

Amides have two “i’s,” whereas esters only have one “i” in
their generic name. Examples of esters include benzocaine,
cocaine, and tetracaine. Examples of amides include
bupivacaine, lidocaine, and mepivacaine. Esters are more
likely to cause an allergic reaction

Question 6

What topical anesthetic reversibly binds to and inactivates sodium channels, thus inhibiting ex-
citation of nerve endings and causing vasocon-
striction?

Answer 6

Cocaine

Question 7

What is the maximum dose of lidocaine hydro-

chloride?

Answer 7

4 to 5 mg/kg, maximum total dose of 300 mg

Question 8

What medication can be given to reverse the

effects of local injectable epinephrine?

Answer 8

Local infusion of 1.5 to 5 mg of phentolamine

Question 9

What is the mechanism of action for β-lactam

antibiotics?

Answer 9

Binds to DD-transpeptidase (also called penicillin-binding protein) and inhibits the formation of peptidoglycan cross-
links in the bacterial cell wall

Question 10

What is the mechanism for acquiring penicillin

resistance?

Answer 10

Enzymatic deactivation of penicillin G through β-lactamases

and altered penicillin binding proteins

Question 11

What is the mechanism of action of aminoglyco-

sides?

Answer 11

They irreversibly bind to the 30S ribosome and freeze the
30S initiation complex. Additionally, they cause misreading
of the mRNA code (bactericidal).

Question 12

A mutation in which a gene may lead to increased

aminoglycoside toxicity even at low doses?

Answer 12

Mitochondrial 12S ribosomal RNA gene

Question 13

What are the earliest signs of aminoglycoside

ototoxicity?

Answer 13

Tinnitus, high-frequency hearing loss, and dizziness

Question 14

What is the mechanism of action of macrolides?

Answer 14

They inhibit translocation of the peptidyl tRNA from the A
to the P site on the ribosome by binding to the 50S
ribosomal RNA (bacteriostatic).

Question 15

What is the treatment of Clostridium difficile colitis?

Answer 15

IV or oral (PO) metronidazole or PO vancomycin

Question 16

What are the most common antibiotics that have
been implicated in the development of C. difficile
colitis?

Answer 16

Second- and third-generation cephalosporins, ampicillin/

amoxicillin, and clindamycin

Question 17

A child develops gray staining of the teeth with a
prominent horizontal line across the upper and
lower teeth after being prescribed an antibiotic.
Which antibiotic was most likely prescribed?

Answer 17

Tetracycline

Question 18

What is the mechanism of action of aspirin?

Answer 18

Irreversible acetylation of serine 529 of cyclooxygenase
(COX) 1. Rapid onset of action if dose is 160 mg or greater.
The effects of use last for the lifetime of the platelet, which
is 7 to 10 days.

Question 19

What is the mechanism of action of thienopyr-

adines (e.g., clopidogrel bisulfate)?

Answer 19

Irreversible inhibition of the cysteine residue of the P2Y12
platelet receptor. Onset of action is rapid if patient is given a
loading dose, and the effects last for the lifetime of the
platelet (7 to 10 days).

Question 20

What drug can be given to reverse the antiplatelet
effects of nonsteroidal anti-inflammatory drugs
(NSAIDs)?

Answer 20

Desmopressin acetate (DDAVP)

Question 21

In the event of significant bleeding following
administration of heparin, what medication should
be considered?

Answer 21

Protamine. Give 1 mg for every 100 units of heparin, and
closely monitor activated partial thromboplastin time
(aPTT).

Question 22

What is the mechanism of action of warfarin?

Answer 22

It is a vitamin K antagonist that inhibits the production of

vitamin K-dependent clotting factors.