Aminoglycosides (6 - 10)
- 1.
A 76-year-old man is seen in a hospital emergency department complaining of pain in and behind the right ear. Physical examination shows edema of the external otic canal with purulent exudate and weakness of the muscles on the right side of the face. The patient informs the physician that he is a diabetic. Gram stain of the exudate from the ear shows many polymorphonucleocytes and gram-negative rods, and samples are sent to the microbiology laboratory for culture and drug susceptibility testing. A preliminary diagnosis is made of external otitis. At this point, which of the following is most appropriate?
- A.
Amikacin should be injected intramuscularly, and the patient should be sent home
- B.
Analgesics should be prescribed, but antibiotics should be withheld pending microbiological results
- C.
Oral cefaclor should be prescribed together with analgesics, and the patient should be sent home
- D.
The patient should be hospitalized, and treatment started with imipenem-cystatin
- E.
The patient should be hospitalized, and treatment started with gentamicin plus ticarcillin
Correct Answer
E. The patient should be hospitalized, and treatment started with gentamicin plus ticarcillinExplanation
The diabetic patient with external otitis is at special risk because of the danger of spread to the middle ear and possibly the meninges, so hospitalization is advisable, especially in the elderly. Likely pathogens include E coli and Pseudomonas aeruginosa, and coverage must be provided for these and possibly other gram-negative rods. The combination of an aminoglycoside plus a wider spectrum penicillin is most suitable in this case and is synergistic against many pseudomonas strains. Imipenem-cilastatin is also possible, but resistant strains of P aeruginosa have emerged during treatment. Cefaclor lacks antipseudomonal activity.
For more visit www.rimemcq.comRate this question:
-
- 2.
Regarding the toxicity of aminoglycosides which statement is accurate?
- A.
Gentamicin and tobramycin are the least likely to cause renal damage
- B.
Ototoxicity due to amikacin and gentamicin includes vestibular dysfunction, which is often irreversible
- C.
Ototoxicity is reduced if loop diuretics are used to facilitate the renal excretion of aminoglycoside antibiotics
- D.
Reduced blood creatinine is an early sign of aminoglycoside nephrotoxicity
- E.
Skin reactions are very rare following topical use of neomycin
Correct Answer
B. Ototoxicity due to amikacin and gentamicin includes vestibular dysfunction, which is often irreversibleExplanation
Gentamicin and tobramycin are the most nephrotoxic aminoglycosides. The incidence of nephrotoxic effects with gentamicin is 2 to 3 times greater than the incidence of ototoxicity. With traditional dosage regimens, the first indication of potential nephrotoxicity is an increase in trough serum levels of aminoglycosides, which is followed by an increase in blood creatinine. Although aminoglycoside ototoxicity usually involves irreversible effects on vestibular function, hearing loss can also occur. Ototoxicity is enhanced by loop diuretics. Skin reactions are common with topical use of neomycin.
For more visit www.rimemcq.comRate this question:
-
- 3.
This drug has characteristics almost identical to those of gentamicin but has much weaker activity in combination with penicillin against enterococci.
- A.
Amikacin
- B.
Erythromycin
- C.
Netilmicin
- D.
Spectinomycin
- E.
Tobramycin
Correct Answer
E. TobramycinExplanation
Tobramycin is almost identical to gentamicin in both its pharmacodynamic and pharmacokinetic properties. However, for reasons that are unclear, it is much less active than either gentamicin or streptomycin when used in combination with a penicillin in the treatment of enterococcal endocarditis.
For more visit www.rimemcq.comRate this question:
-
- 4.
Your 23-year-old female patient is pregnant and has gonorrhea. The medical history includes anaphylaxis following exposure to amoxicillin. The most appropriate drug to use is
- A.
Azithromycin
- B.
Cefixime
- C.
Ceftriaxone
- D.
Ciprofloxacin
- E.
Doxycycline
Correct Answer
A. AzithromycinExplanation
All of the listed drugs have been used for the treatment of gonorrhea. Cephalosporins should be avoided in patients with a history of severe hypersensitivity to penicillins, and fluoroquinolones (see Chapter 46) should be avoided in pregnancy. Tetracyclines including doxycycline have been used in the past for gonorrhea, but not as single doses, and they too should be avoided in pregnancy.
For more visit www.rimemcq.comRate this question:
-
- 5.
Which statement about “once-daily” dosing with aminoglycosides is not accurate?
- A.
Dose adjustment is less important in renal dysfunction
- B.
It is convenient for outpatient treatment
- C.
Less nursing time is required for drug administration
- D.
Often fewer side effects than multiple (conventional) dosing regimens
- E.
Underdoing is less of a problem
Correct Answer
A. Dose adjustment is less important in renal dysfunctionExplanation
In “once-daily dosing” with aminoglycosides, the selection of an appropriate dose is particularly critical in patients with renal insufficiency. The aminoglycosides are eliminated by the kidney in proportion to creatinine clearance. Knowledge of the degree of insufficiency, based on plasma creatinine (or BUN), is essential for estimation of the appropriate single daily dose of an aminoglycoside.
For more visit www.rimemcq.comRate this question:
-
Quiz Review Timeline +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
-
Current Version
-
Mar 22, 2023Quiz Edited by
ProProfs Editorial Team -
Dec 21, 2018Quiz Created by
Medicinemcq
Back to top