Streptogramins

Question 1

Streptogramins

Answer 1

Quinupristin/Dalfopristin

One of the first newer drugs to treat VRE and MRSA

2 different drugs given in combo

Brand Synercid: separately they are bacteriostatic; together they act synergistically to give bactericidal activity against some Gram+ cocci

Initially used a lot for VRE

Other streptogramins have been developed and used in animals as growth promoters (>50% of US antibiotics are used here)

Question 2

Streptogramins MOA

Answer 2

Bind to different sites on the 50S subunit of bacterial ribosome to prevent bacterial protein synthesis

Question 3

Streptogramins Spectrum

Answer 3

Good
MSSA / MRSA
Streptococci
Enterococcus faecium (including VRE)

Poor
Enterococcus faecalis
Anything Gram-

Question 4

Streptogramins Adverse Effects

Answer 4

Ideally should be given by central line (can cause phlebitis)

High incidence of myalgias and arthralgias (can limit tolerance to therapy)

Inhibits CYP P450 3A4 (causes drug interactions)

Question 5

Streptogramins Important Facts

Answer 5

Must be mixed and administered with 5% dextrose in water (D5W) solutions only
Drug becomes insoluble and can crystallize when mixed with normal saline
Make sure nurses know how to flush line with D5W or another saline free diluent

The arthralgias and myalgias are significant
Decreasing dose may decrease severity but may compromise efficacy

Indication for VRE E. faecium was removed from labeling due to lack of follow up data after initial approval
No longer first line for VRE

Good for
MRSA or E. faecium infections not responding or intolerant to other meds

Not active against E. faecalis
E. faecalis is more common in hospitals but less likely to be resistant to Vanco
This drug better used for definite therapy rather than empiric
Linez and Dapto don’t have this issue and are generally better options