Aminoglycosides

Question 1

Gentamicin/Tobramycin Peak dosing for uncomplicated lower UTIs

Answer 1

3-4 mcg/ml

Question 2

Gentamicin/Tobramycin Peak dosing for gram-positive endocarditis (synergistic effects with PCN)

Answer 2

3-4 mcg/ml

Question 3

Gentamicin/Tobramycin Peak dosing for gram-negative infxn (ex: sepsis)

Answer 3

6-8 mcg/ml

Question 4

Gentamicin/Tobramycin Peak dosing for gram-negative pneumonia

Answer 4

8-10 mcg/ml

Question 5

Gentamicin/Tobramycin Peak dosing for gram-negative pneumonia with CF

Answer 5

12-15 mcg/ml

Question 6

Gentamicin/tobramycin trough

Answer 6

< 1-2 mcg/ml

Question 7

Aminoglycosides time to sample for peak

Answer 7

Should be drawn 0.25 - 1 hour after a 1hr infusion

Question 8

Aminoglycosides time to sample for trough

Answer 8

should be drawn 30 minutes or less before the next dose

Question 9

Aminoglycosides time to sample for a random drawing after the first dose

Answer 9

The random should be drawn at least one half-life from the peak concentration

Question 10

Aminoglycosides time to sample for a random drawing after dialysis

Answer 10

Wait at least 2 hours for redistribution to take place before drawing a concentration

Question 11

AE and toxicity of Aminoglycosides

Answer 11

Nephrotoxicity, neurotoxicity, ototoxicity

Question 12

Nephrotoxicity d/t aminoglycosides

Answer 12

May occur w/in 4-5 days
Non-oliguric
Reversible in most cases
Similar risk with gent, tobra, and amikacin
Risk factors: other disease states, age, other nephrotoxic drugs

Question 13

Neurotoxicity d/t aminoglycosides

Answer 13

Muscle twitching, numbness, seizures, tingling

Question 14

Ototoxicity d/t aminoglycosides

Answer 14

0.5-3% clinical incidence
Damage to 8th cranial nerve
Unilateral/bilateral
Variable onset

Question 15

Cochlear ototoxicty

Answer 15

loss of hearing, tinnitus, feeling of ear fullness

Often irreversible

Question 16

Vestibular ototoxicty

Answer 16

Vertigo, ataxia, nystagmus, dizziness, N/V, unsteadiness

Often irreversible

Question 17

Drug-drug interactions of aminoglycosides that can have a possible additive nephrotoxicity

Answer 17

Amphotericin B
Cisplatin
CsA
Lasix

Question 18

Drug-disease interactions with aminoglycosides: ascites

Answer 18

May increase Vd by greater than or equal to 25%

Question 19

Drug-drug interactions with aminoglycosides and skeletal muscle relaxants

Answer 19

Aminoglycosides are capable of producting neuromuscular blockade which can enhance the activity of the muscle relaxants

Question 20

Drug-disease interactions with aminoglycosides: Burns

Answer 20

Increase clearance and/or decrease t1/2

Question 21

Drug-disease interactions with aminoglycosides: cancer

Answer 21

Increased Vd

Question 22

Drug-disease interactions with aminoglycosides: Critically ill with sepsis

Answer 22

May increase or decrease Vd and clearance

Question 23

Drug-disease interactions with aminoglycosides: fever

Answer 23

Increased clearance

Question 24

Drug-disease interactions with aminoglycosides: hemodialysis/peritoneal dialysis

Answer 24

Increased clearance and decreased t1/2

Question 25

Drug-disease interactions with aminoglycosides: intensice care setting

Answer 25

may increase Vd up to 25-50%

Question 26

Drug-disease interactions with aminoglycosides: Post-op/mechanical ventilation

Answer 26

may increase Vd

Question 27

Drug-disease interactions with aminoglycosides: Postpartum

Answer 27

may increase Vd

Question 28

Drug-disease interactions with aminoglycosides: surgery

Answer 28

increases Vd

Question 29

Distribution of aminoglycosides

Answer 29

Rapid
Related to intracellular fluid
Low protein binding
Poor CSF penetration
High concentrations in kidney, liver and lung
Accumulation over time
Influenced by age, wt, dx/conditions

Question 30

Clearance of aminoglycosides

Answer 30

90-95% fraction excreted via kidney
Relationship b/n drug clearance and renal function (GFR, CrCl)
Dialyzable
Influenced by age, dx/conditions