Anti-microbials 2

Question 1

Antibiotics that can cause renal dysfunction

Answer 1

Vancomycin

Aminoglycosides

Question 2

Are bactericidal or bacteriostatic Abx favoured?

Answer 2

Bactericidal

Question 3

Bactericidal Abx

Answer 3

(Very Finely Proficient At Cell Murder) - Vancomycin, Fluorquinolones, Penicillins, Aminoglycosides, Cephalosporins, Metronidazole

Question 4

Bacteriostatic Abx

Answer 4

(ECSTaTiC)
Erythromycin
Clindamycin
Sulfamethoxazole
Trimethoprim
Tetracycline
Chloramphenicol

Question 5

4 phamacodynamic / kinetic parameters

Answer 5

• Peak concentration over MIC (peak / MIC) - needs to be as high as possible without causing ototoxicity / nephrotoxicity
• Trough level (24h AUC/MIC)
• Time above MIC (time > MIC)
• Total Abx given (AUC)

Question 6

Pharmacodynamic type 1

Aminoglycosides

Answer 6

E.g. aminoglycoside

• Need high peak/MIC
• Prevent high 24h AUC/MIC to avoid toxicity

Want to get peak/MIC as high as possible without excessive side effects that occur at high doses (nephrotoxicity, ototoxicity) - if not high enough increase dose; want to make sure Abx is not accumulating by making sure 24h AUC/MIC is not too high - if too high reduce frequency (e.g. give every 48h rather than 24h) as do not want to reduce dose to compromise peak. Therefore usually given as one big dose per day

Question 7

Pharmacodynamic type 2

Penicillins

Answer 7

• Need high time >MIC

Multiple frequent smaller doses as the parameter important for their action is a prolonged time>MIC. Should also be 6 hourly throughout day and night, and may even consider infusions

Question 8

Pharmacodynamic type 3

Answer 8

Vancomycin
- Maximise amount of drug

Usually given infusion

Question 9

Abx treatment length meningitis

Answer 9

7 days

Question 10

Abx treatment length osteomyelitis

Answer 10

6 weeks

Question 11

Abx treatment length endocarditis

Answer 11

4-6w (worry about long-term sequelae like rheumatic fever)

Question 12

Abx treatment simple cystitis (women)

Answer 12

3 days

Question 13

Skin infection

Answer 13

Need to cover SA + Strep

Flucloxacillin (vancomycin if MRSA or penicillin allergy)
+ Clindamycin if very aggressive

Question 14

Pharyngitis

Answer 14

Group A Strep

Benzylpenicillin 10d

Question 15

Typical CAP

Answer 15

Penicillin sensitive

Mild: Amoxicillin 5-7d (clarithromycin if pencillin allergy)

Moderate / severe: Co-amoxiclav + Clarithromycin (+ hospital admission)

If S aureus: Flucloxacillin

Question 16

MRSA

Answer 16

Vancomycin

Question 17

Atypical CAP - mycoplasma / chlamydia

Answer 17

Clarithromycin or doxycycline

Question 18

Atypical CAP - Legionella

Answer 18

Clarithromycin + Rifampacin

Question 19

Atypical CAP - PCP

Answer 19

Co-trimoxazole (Septrin)

Question 20

Bacterial meningitis

Answer 20

Ceftriaxone (+ Amoxicillin if listeria likely)

Question 21

UTI

Answer 21

Community: Trimethoprim or nitrofurantoin
Hospital: Cephalexin or Augmentin

Question 22

HAP

Answer 22

Ciprofloxacin +/- Vancomycin

If ITU: Piptazobactam + Vancomycin (MRSA more likely)

Question 23

C difficile colitis

Answer 23

Stop offending Abx (usually cephalosporin)
PO metronidazole
If fails PO vancomycin