pharm-last bit!! misc antibiotics
Terms
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What is Chloramphenicol used for?
How is it administered? -
Last resort! Wide spectrum of coverage--aerobic/anaerobic G+/G- microbes.
Available IV ONLY - What is the downside to Chloroamphenicol?
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Serious side effects:
--fatal blood dyscrasias
--hemolytic anemia
--leukopenia
--thrombocytopenia
--fatal aplastic anemia - What is Chloramphenicol an alternate for?
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Alt to:
doxycycline for Rocky Mountain Spotted Fever (Rickettsia)
Fluoroquinolones and ceftrixone for Salmonella typhi (typhoid fever)
Gentamicin for Yersinia pestis (plague) - What is the mechanism of Chloramphenicol?
- Acts same as tetracyclines: inhibits binding of aminoacyl-tRNA to acceptor site
- What is the problem with Chloramphenicol that leads to side effects?
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inhibits MAMMALIAN mitochondrial protein synthesis.
Erythropoietic cells are most sensitive (progenitor cells--not mature RBCs b/c they lack nuclei!)
Results in leukopenia, thrombocytopenia, fata aplastic anema. - How does hemolytic anemia result from Chloramphenicol use?
- decrease G6PDH
- What causes Gray Baby Syndrome?
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High levels of Chloramphenicol in system due to:
insufficient glucuronyl transferase to conjugate the drug.
underdeveloped renal function in the baby. Baby is unable to eliminate the drug. - What do increased Chloramphenicol levels cause?
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interference w/ mictochondrial ribosomes which cause:
1. depressed respiration
2. cardiovascular collapse
3. cyanosis (grey pallor) - How is Quinupristin/Dalfopristin administered?
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IV for MRSA and vancomycin resistant infections.
Work synergistically - What class of drug is Quinupristin/Dalfopristin?
- a streptogramin
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What is the mechanism of Quinupristin?
Dalfopristin? -
Both Quinupristin and Dalfopristin--release peptidyl-tRNA from the DONOR site of peptidyltransferase
In addition, Dalfopristin--inhibits binding of amino acyl-tRNA from the ACCEPTOR site and of peptidyl-tRNA to the donor site of peptidyltransferase. - What does Quinupristin/Dalfopristin inhibit?
- CYP3A leads to a decrease in drug metabloism. (be careful when using warfarin and diazepam)
- What are the side effects of Quinupristin/Dalfopristin?
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superinfection --pesudomembranous colitis
Arthalgias/myalgia
hyperbilirubinemia - What is Linezolid used for and how is it administered?
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use for MRSA and vancomycin resistant infections.
Oral AND IV - What are the side effects of Linezolid and what should be done to minimize them?
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colitis, myelosuppression resulting in blood dyscrasias.
Recommend weekly CBC - What is the mechanism of Linezolid?
- prevents formation of initiation complex. Inhibition of protein synthesis.
- What kind of toxicity might linezolid cause?
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5-HT toxicity when used with drugs taht enhance 5-HT
--What is 5-HT???-- - What are the uses of clindamycin?
- alternative for Bacteroides fragilis, Corynebacterium diptheria
- What is the major side effect of Clindamycin?
- pseudomembranous colitis C difficile
- What is the route of administration for Clindamycin?
- oral, IV, topical for acne, suppository for bacterial vaginosis.
- What is the mechanism for Clindamycin?
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same as that of erythromycin
inhibits the translocation of the aminoacyl tRNA from the acceptor to the donor site. - What is Polymixin B effective against?
- G - organisms
- What type of toxicity does Polymixin exhibit?
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nephro and neurotoxic
this is why it is limited to topical use. - What is the mechanism of Polymixin B?
- Cidal--cationic detergent. Dissolves membrane.
- What is Polymixin B used for?
- common bacterial infection of the conjunctiva and eyelids
- What are the common combinations of Polymixin B?
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Neosporin= polymixin B + bacitracin + neomycin
Polysporin = bacitracin + polymixin B
Polytrim = polymixin B and TMP - How many times should Spectinomycin be used?
- EXCLUSIVELY as a single dose IM for Gonorrhea in patients w/ allergy to PCN or for PCN resistant strains of gonorrhea.
- What does Rifacimin treat?
- travelers diarrhea from noninvasive strains of E. coli
- What is Muripocin used for? What is its pitfall?
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ointment and cream.
Alternate for Impetigo from group A Strep or Staph aureus. [first choice is diclocacillin]
Pitfall is price - What is the mechanism of Muripocin?
- binds bacterial isoleucyl t-RNA synthetase
- What is Nitrofurantoin used for?
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treatment and prevention of UTI.
Use if local E. Coli is >20%.
Can color urine brown