Amino glycosides

Question 1

Suffix for Amino glycosides

Answer 1

Mycin
Micin
Cin

(Thromycin is always used for Macrolides)

Question 2

Amino glycoside mechanism

Answer 2

Act on 30S ribosomal subunit
Inhibit protein synthesis
Bactericidal
Always used with another agent

Question 3

Route of Admin

Answer 3

IV

Neomycin topical

Question 4

Spectrum

Streptomycin

Answer 4

Plague
Tularemia
Gram +ve cocci (with penicillin)
Mycobacterium tuberculosis (with other anti tb)

Question 5

Indications

Answer 5

As adjuncts:
Acute Brucellosis (tetracycline)
Infective endocarditis (gentamicin)( streptococcus viridans)
Complicated UTIs
Complicated skin and soft tissue infection
Bacteremia
Peritonitis
Meningitis
Septicemia
Osteomyelitis
Pneumonia (cephalosporin or penicillins)

Monotherapy: streptomycin
Tularemia
Plague

Neomycin:
Pre operative bowel sterilization
Hepatic coma (adjunct)
Skin mucous membrane infection (topically)

Question 6

Amikacin

Answer 6

Aerobic & anaerobic gram -ve bacteria :

M tuberculosis & Mycobacterium Avium intracellulare (MAI)

Question 7

Gentamicin

Answer 7

Staphylococcus strains

More active against Serratia than tobramycin

Question 8

Netlimicin

Answer 8

Gentamicin resistant organisms

Less ototoxicity than other Amino glycosides

Question 9

Neomycin

Answer 9

E. Coli
Klebsiella pneumoniae
Gram -ve organisms
Gram +ve organisms such as S. Aureus)

Question 10

Tobramycin

Answer 10

Pseudomonas aeruginosa (more active than gentamicin)

Question 11

Adverse effects

Answer 11

Ototoxicity

Nephrotoxicity

Neuromuscular Blockade

Hypersensitivity

Question 12

Ototoxicity

Answer 12

Streptomycin = kanamycin > Amikacin = gentamicin = tobramycin > netlimicin

Vestibular damage : (tinnitus, vertigo, ataxia)
gentamicin & streptomycin
Bilateral , irreversible

Auditory damage: (Hearing loss)
Amikacin, Kanamycin, Neomycin

Both : Tobramycin

Question 13

Nephrotoxicity

Answer 13

Since AMGs Accumulate in proximal tubule , MILD renal toxicity is produced in 25% patients

Usually reversible

ODA once daily dose is less nephrotoxic

Neomycin most nephrotoxic
Streptomycin least nephrotoxic
Gentamicin & tobramycin same toxic

Trough level > 2 ug/ml gentamicin
Trough level > 10 ug/ml Amikacin
Are associated with nephrotoxicity

Question 14

Neuromuscular Blockade

Answer 14

High dose therapy
Concurrent admin of a neuromuscular blocker or anaesthetic
Pre existing hypocalcemia
Myasthenia gravis
Intraperitoneal or rapid IV drug admin

Apnea respiratory depression may be reversed with admin of Ca or anticholinesterase

Question 15

Therapeutic levels

Answer 15

Traditional dosing:
Gentamicin & Tobramycin peak at 6 to 10 ug/ml

ODA:
16 to 20 ug/ml or 8 to 10 times the MIC of targeted bacteria.
Trough level is 0.5 - 1.5 ug/ml

Amikacin :
Peaks at 25 to 30 ug/ml.
Trough level is 5 to 8 ug/ml

Question 16

Interactions

Answer 16

IV loop diuretics (increased ototoxicity)

Increased nephrotoxicity:
Other Aminoglycosides
Cisplatin
Amphotericin B