Abx for gram positive infections

Question 1

Vancocin

Answer 1

Vancomycin
Class: Glycopeptides
Capsule, PO solution, Injection
Use: 1st line for mod-severe systemic MRSA infections
Warnings:
- Ototoxicity
- Nephrotoxicity
- do not infuse faster than 1 g/hr -> vanco infusion rxn
Monitor:
- renal function
- drug levels

Question 2

Vancocin level monitoring: serious infections (bacteremia, sepsis, endocarditis, pneumonia, osteomyelitis, meningitis)

Answer 2

AUC/MIC ratio goal 400-600
SS trough goal 15-20 mcg/mL

take SS trough 30 min before 4th or 5th dose

Question 3

Vancocin level monitoring: non-serious infections

Answer 3

SS trough goal 10-15 mcg/mL

Question 4

Vancocin dosing:
Systemic Infections (IV only)

Answer 4

15-20 mg/kg Q8-12H
using total body weight

CrCl 20-49 -> Q24H

Question 5

Vancocin dosing: C. difficile

Answer 5

125 mg PO QID x 10 days

Question 6

Vancomycin DDI

Answer 6

• caution with other nephrotoxic drugs
• caution with other ototoxic drugs (aminoglycosides, cisplatin, loop diuretics)

Question 7

Cubicin

Answer 7

Daptomycin
Class: cyclic lipopeptide
IV
concentration-dependent activity against most gram+ bacteria inc staph (MRSA) & enterococci (VRE). No gram negative activity
DO NOT USE to treat pneumonia (inactivated in the lungs)
Warnings:
- myopathy & rhabdomyolysis
- can falsely inc PT/INR
ADE:
- inc CPK (evidence of myopathy)
Monitoring:
- CPK weekly

Question 8

Cubicin DDI

Answer 8

additive risk of muscle toxicity with statins

Question 9

Zyvox

Answer 9

Linezolid
Class: oxazolidinones
similar activity to vancomycin + VRE
CI:
- DO NOT USE within 2 weeks of MAOi
Warnings:
- duration related myelosuppression (thrombocytopenia)
- optic neuropathy
- serotonin syndrome
- hypoglycemia
ADE:
- thrombocytopenia
Monitor:
- weekly CBC
Notes:
- do not shake linezolid suspension

Question 10

Zyvox renal dose adjustments & IV:PO ratio

Answer 10

no renal adjustments

1:1

Question 11

Zyvox DDI

Answer 11

• reversible MAOi -> avoid tyramine rich foods & serotonergic drugs
• Linezolid can exacerbate hypoglycemic episodes -> caution in pts on insulin

Question 12

Synercid

Answer 12

Quinupristin/Dalfopristin
IV
active against most gram positive bacteria
- Staph (MRSA)
- Enterococci (VRE caused by E. faecium but NOT E. faecalis)
ADE:
- NOT WELL TOLERATED
- arthralgias/myalgias
- infusion reactions
- hyperbilirubinemia
Admin:
- dilute in D5W only
- admin via central line