10th lecture - gram negative antibiotics

Question 1

Main gram neg- AB group is?
(and give product examples)

Answer 1

Aminoglycosides, such as:

Streptomycin
Dihydrostreptomycin
Neomycin
Kanamycin
Amikacin
Gentamicin
Tobramycin

Question 2

Name another group of gram neg. AB in addition to aminoglycosides

Answer 2

Aminocyclitols, such as:
Spectinomycin
Apramycin

Question 3

Aminoglycosides primarily act against

Answer 3

gram-negative microbes. The effect on gram-positive microbes is limited. They act against some mycobacteria and mycoplasmas.

Question 4

Aminoglycosides mechanism of action

Answer 4

Bactericidal, inhibit the microbial cell protein synthesis.

Question 5

Aminoglycosides half-life

Answer 5

Short half-life (1-2 hours).

Question 6

Aminoglycosides Pharmacokinetics, excretion

Answer 6

Primarily excreted through the kidneys, but accumulate in the kidney tissue (caution in case of renal impairment), medication residues remain in the kidneys for a long period of time which is why the “varoaika”/withdrawal period is long.

Question 7

Aminoglycosides Interactions/synergism

Answer 7

There is synergistic activity of aminoglycosides in combination with beta-lactam antibiotics.

They also enhance the potency of muscle relaxants and induce neuromuscular blockade (anesthetics).

Question 8

Aminoglycosides Toxicity

Answer 8

are some of the most toxic antibiotics
(2nd most toxic to be more specific, only 2nd to chloramphenicol/broad spectrum-AB).

Long-term therapy and administration of high doses (mainly neomycin and gentamicin) will lead to nephrotoxicity (acute tubular necrosis).

Treatment with aminoglycosides must be as short-term as possible, however it must be sufficient to destroy the microbes.

Question 9

Aminoglycosides Side effects

Answer 9

Side effects are ototoxicity and nephrotoxicity (and neurotoxicity).

They cause both vestibular and cochlear damage. The potency of the ototoxic effect is increased by furosemide-type diuretics.

Question 10

when administered IV Aminoglycosides do what

Answer 10

They slow down heart function and decrease blood pressure.

Question 11

Oldest 2 aminoglycosides?

Answer 11

Streptomycin and
dihydrostreptomycin

Question 12

Streptomycin and dihydrostreptomycin side effects

Answer 12

Generally no side effects occur if treatment is less than a week in duration.

In case of long-term treatment they may lead to vestibular damage, ataxia, abnormal coordination and there have been cases of deaths.

Neuromuscular blockade risk when administered with anesthetics.

Question 13

the most toxic aminoglycoside is

Answer 13

neomycin

Question 14

Neomycin most frequent side effect is

Answer 14

kidney failure, death.

It is not recommended to administer through the parenteral route.

Question 15

Neomycin is mainly used for

Answer 15

topical treatment of skin infections, as well as intramammary treatment of mastitis.

e.g. neosporin, bacibact

Question 16

Name 2 aminoglycosides that are Similar to neomycin but less toxic.

Answer 16

Kanamycin and amikacin

Amikacin is a chemical modification of kanamycin. Its nephrotoxicity and neurotoxicity is slightly lower than that of kanamycin.

Question 17

Name one of the most commonly used aminoglycosides.

Answer 17

Gentamicin

Question 18

Primary side effects of gentamicin

Answer 18

nephrotoxicity and neurotoxicity, particularly in the event of long-term treatment.

The damage is mostly reversible (but nevertheless that depends on the duration of treatment).

Medical residue will remain in the tissue for a long period of time, especially in the kidneys.

Question 19

Name an AB belonging to the Aminocyclitol antibiotics group.

Answer 19

This class includes kanamycin, neomycin, gentamicin, apramycin, spectinomycin.

Question 20

Spectinomycin (an aminocyclitol) is less toxic compared to

Answer 20

aminoglycosides. its use is limited due to resistance emerging quickly.

Question 21

Spectinomycin (Aminocyclitol antibiotic) side effetcs and synergism.

Answer 21

As a rule, it does not cause nephrotoxicity and neurotoxicity, however it does increase the potency of neuromuscular blockade.

Question 22

What classes of AB are effective against gram neg. bacteria?

Answer 22

Aminoglycosides and aminocyclitols

Question 23

Other antibiotics (other than aminoglycosides and aminocyclitols) with effect against gram negative microbes are (2)

Answer 23

polymyxins like colistin. (polypeptide AB)

only administered parenterla because no GI absorption.

Not recommended for use in vet med!