Topic 16-Clindamycin. Streptogramins. Oxazolidinones Flashcards
What drug is part of the Lincosamide family?
Clindamycin
What is the mechanism of action of Clindamycin?
Binds and inhibits the 50s ribosomal subunit
Spectrum of Clindamycin
Narrow spectrum
Similar to macrolides
Effective against gram positive aerobes, gram negative anaerobes MRSA, staph, strep, clostridium (not dificile) fusibacterium, bacteroids fragilis
Intracellular- chlamydia and legionella (not mycoplasma)
protozoa- pneumocystis jirovecci (alternative compound)
plasmodium flaciparum (combination therapy
Toxoplasma (alternative) compound
NOT effective against gram negative aerobes or respiratory tract infections, and clostridium dificile
Pharmacokinetics of Clindamycin Administration Absorption Penetration Excretion
IV, IM, or oral (every 8 hours)
good absorption
good penetration/distribution including bone, intracellularly, abscess (not CNS)
Excreted in bile
Adverse effects of Clindamycin
ABX associated pseudomembrane colitis
Rash
Neutropenia
Maybe blocks neuromuscular junction
Clinical use of Clindamycin
Staph infectins and mixed aerobic and anaerobic infections
toxic shock syndrome
odontogenic infection, osteomyelitis, skin, soft tissue infection (MRSA+strep+staph)
diabetic food (have to combine therapy with aminoglycosides to effectively treat gram negative aerobes)
aspiration pneumonia
secondary peritonitis, trauma wound
pneumocystis jiroveci (alternative
What is the first and second choice drug in pneumocystis jiroveci?
- )suphamexozale and trimethoprim
2. )Clindamycin
What drug is used in combination therapy in plasmodium falciparum infection?
Clindamycin
What is the first and second choice drug in toxoplasma infection?
1.)clindamycin?
What is the resistance called for Clindamycin? Which bacteria is also resistant
MLS resistance. Enterococci.
What is the rule about above and below the waist antibiotics?
Above the waist is gram positive anaerobes treated by clindamcyin
Below the waist is gram negative anaerobes treated by metronidazole
What are the two Streptogramin drugs that are given together and potentiate each other
Dalfopristin and quinupristin
What is the spectrum of dalfopristin and quinupristin?
Narrow spectrum
Gram positive cocci (multidrug resistanct)
Including MRSA, VRSA, enterococci, pneumococci (slow E. Faecium effectiveness)
Intracellular pathogens
What is the mechanism of action for quinupristin?
Binds to a nearby site on the 50S ribosomal subunit and prevents elongation of the polypeptide
What is the mechanism of action for dalfopristin?
binds to the 23S portion of the 50S ribosomal subunit, and changes the conformation of it, enhancing the binding of quinupristin by a factor of about 100. In addition, it inhibits peptidyl transfer.
Pharmacokinetics of dalfopristin and quinupristin Bactericidal or bacteriostatic Administration Half life PAE Metabolism Interaction Penetration Distribution Elimination
Bacteriostatic alone but together they are bactericidal
Administered parenterally (IV) every 8-12 hours
Half life is short
10 hour effectiveness after treatment(Post antibiotic effect)
Metabolized in liver
Inhibits CYP3A4
Penetrates 30-40 times higher concentration intracellularly
Good distribution
Eliminated in bile
Clinical indications of dalfopristin and quinuprisitn
Vancomysin resistant E. faecium and multi-drug resistant bacteremia
Sepsis-life threatening infection
RESERVE DRUG
Adverse effects of of dalfopristin and quinupristin
Phlebitis (given in central vein as precaution)
Athralgia-myalgia
What are the two Oxazolidinones drugs
Linezolid and tedizolid
What is the mechanism of action of linezolid
Special binding on the 23S rRNA of 50s subunit inhibiting the 70s initiation complex (NOT PART OF MLS resistance)
Spectrum of Linezolid
Narrow spectrum, RESERVE Gram positive rods and cocci (aerobe and anaerobe) effective against enterococcus (both faecalis and faecium)-some resistance is building VRSA, MRSA pneumococci cornybacteria mycobacterium tuberculosis pasteurella multocida
Pharmacokinetics of Linezolid Bactericidal or bacteriostatic Administration Absorption Distribution Concentration or time based effect Elimination
Bacteriostatic, but bactericidal against streptococci
oral or parenteral 2 times a day
good oral absorption
Goes into CNS and intracellularly
Time based effect
Eliminated in kidney and bile (patient with kidney issue doesn’t need to switch does cause will also be excreted in bile)
Adverse effect of Linezolid
Candidiasis
Bone marrow suppression
Weak MAO inhibitor (cheese effect, serotonin syndrome, and antidepressant effect)
Doesn’t inhibit CYP enzyme
Indications for Linezolid
Reserve, life threatening severe infections
pneumonia, MRSA and VRSA
Enterococci
