Antibiotics

Question 1

List the classes of antibiotics?

Answer 1

Beta-lactams
Aminoglycosides
Quinolones
Macrolides
Tetracyclines
(Co-trimoxazole)
(Metronidazole)

Question 2

List the different “classes” under beta-lactams?

Answer 2

Penicillins
Aminopenicillins
Cloxacillins and Flucloxacillin
Cephalosporins

Question 3

List the penicillin agents and their route of administrations?

Answer 3

Benzyl penicillin (penicillin G) - IV
Penicillin V - oral
Benzathine penicillin - IMI
Procaine penicillin - IMI

Question 4

Duration of action for the IMI penicillins?

Answer 4

Benzathine penicillin = 21 days

Procaine penicillin = 12 hours

Question 5

Penicillins are the drugs of choice for?

Answer 5

Strep infection
Syphilis
Enterococci
Lysteria

Question 6

What is the cover of aminopenicillins and what are they thus useful for?

Answer 6

Same cover as penicillin PLUS heaemophilus cover

Therefore, URTI (excluding strep.)

Question 7

The use of cloxacillin and flucloxacillin?

Answer 7

Staph aureus cover

Question 8

Route of administration for clox and fluclox?

Answer 8

Cloxacillin IVI

Flucloxacillin PO

Question 9

What agent should be used in cloxacillin-resistant staph aureus infection?

Answer 9

Vancomycin

Question 10

What is the indication for vancomycin?

Answer 10

Cloxacillin resistant Staph aureus

Question 11

Examples of cephalosporins and uses?

Answer 11

1st generation: cefazolin (IV) - surgical prophylaxis
2nd generation: cefuroxime (not really used)
3rd generation: cefotaxime, ceftriaxone - S pneumoniae cover, good CSF penetration therefore treatment of choice for bacterial meningitis, typhoid and gonorheoa

Question 12

Ceftriaxone indications?

Answer 12

S pneumonia
Bacterial meningitis
Typhoid
Gonorrhoea

Question 13

Mode of action of beta-lactams?

Answer 13

Cell wall destruction/bactericidal

Question 14

Therapeutic index of beta-lactams?

Answer 14

Wide

Question 15

How are beta-lactams excreted?

Answer 15

Renally

Question 16

Biggest problem with beta-lactams?

Answer 16

Hypersensitivity
Within one hour: anaphylaxis
Within 72 hours: urticaria, angioedema, bronchospasm, maculopapular rash

Question 17

Maculopapular rash is most commonly associated with which beta-lactam?

Answer 17

Amoxicillin

Question 18

Mechanisms of beta-lactam resistance and how to overcome it?

Answer 18

Beta-lactamase - clavulanic acid (i.e. co-amoxiclav) or tazobactam
Penicillin binding proteins - increase dose

Question 19

Examples of aminoglycosides?

Answer 19

Gentamycin

Kanamycin

Question 20

MoA of aminoglycosides?

Answer 20

Inhibits protein synthesis

Question 21

Cover of aminoglycosides (gram positive and/or negative and/or anerobes?

Answer 21

Gram negative

Question 22

Other properties of aminoglycosides?

Answer 22

Poor tissue penetration, must be given IV
Concentrates in urine
Single daily dosing
Needs to be monitored if in use >3 days or renal impairment

Question 23

Toxic effects of aminoglycosides?

Answer 23

Ototoxicity

Nephrotoxicity

Question 24

Indications for gentamycin?

Answer 24

SERIOUS community acquired infections
Pyelonephritis
Use for synergy with Beta-lactams

Question 25

Indications for kanamycin?

Answer 25

TB

Question 26

Mechanism of action of quinolones?

Answer 26

Targets DNA enzymes

Question 27

Toxicity effects of quinolones?

Answer 27

Rash CNS (headaches, seizures etc.) Tendonitis

Question 28

Examples of quinolones?

Answer 28

1st generation: not used 2nd generation: ciprofloxacin 3rd generation: moxifloxacin

Question 29

Indications for use of ciprofloxacin?

Answer 29

Gram negative UTI Dysentery Alternative to aminoglycoside

Question 30

Indications for use of moxifloxacin?

Answer 30

Gram negative and positive | URTI (if beta-lactam allergy)

Question 31

Macrolides are the drugs of choice for?

Answer 31

H pylori Chlamydia cervicitis Chancroid Penicillin allergy

Question 32

Examples of macrolides?

Answer 32

Erythromycin | Azithromycin

Question 33

Which is used more commonly? Erythromycin or azithromycin?

Answer 33

Azithromycin Reasons: Longer half-life Better absorbed

Question 34

Cover of macrolides?

Answer 34

Gram positive

Question 35

MoA of macrolides?

Answer 35

Protein synthesis inhibition

Question 36

MoA of tetracyclines?

Answer 36

Protein synthesis inhibition

Question 37

Toxic effects of tetracyclines?

Answer 37

Photosensitivity Teeth discolouration Nausea and vomiting DO NOT USE IN PREGNANCY OR CHILDREN YOUNGER THAN 8

Question 38

Example of tetracycline?

Answer 38

Doxycycline

Question 39

Indications for doxycycline?

Answer 39

``` Chlamydia STI Malaria prophylaxis Brucellosis Ricketsia Acne (in low doses) ```

Question 40

Uses of cotrimoxazole?

Answer 40

HIV positive: PCP, toxoplasmosis, isospora belli

Question 41

Uses of metronidazole (Flagyl)?

Answer 41

Anerobes Trichomonas Giardia

Question 42

What side effect does metronidazole have?

Answer 42

Disulfaram-like | DO NOT DRINK ALCOHOL

Question 43

MoA of metronidazole?

Answer 43

Targets DNA/DNA enzymes

Question 44

MoA of cotrimoxazole?

Answer 44

Inhibits steps in bacterial folate pathway