Pharm: Antimicrobials Flashcards
Where is Nafcillin and Oxacillin excreted?
Bile
Which penicillin is known to cause interstitial nephritis?
Methicillin
Which penicillin is known to cause neutropenia?
Nafcillin
Which cephalosporins are excreted mainly in bile?
Ceforperazone and Ceftriaxone
What is the main route for elimination of penicillins and cephalosporins?
Renal excretion
Which penicillin undergoes enterohepatic recycling?
Ampicillin
Which two 3rd generation Cephalosporin are unable to penetrate the BBB?
Cefoperazone and Cefixime
Which penicillin causes interstitial nephritis?
Methicillin
The methylthiotetrazole group in cefamandole cefoperazone and cefotetan cause which 2 adverse effects?
Disulfiram reactions with alcohol and hypoprothrombinemia
Besides cefoxitin give another cephalosporin with activity agains B. frag.
Cefotetan
Aztreonam only has activity against?
Gram negative bacteria
Cilastin given with imipinem is an inhibitor of?
Renal dehydropeptidase 1
Rapid infusion with vancomycin results in?
Red man syndrome
Among protein synthesis inhibitors chloramphenicol and tetracyclines are known to have: A. Broad B. Moderate C. Narrow Spectrum of activity?
Broad
Chloramphenicol is usually bacteriostatic except for the following organisms in which it is cidal.
No Boyfriend (Since) HS Neisseria meningitidis Bacteroides spp (Streptococcus pneumoniae) Haemophilus influenzae
Note: S. pneumo not mentioned in Katzung but included in lecture
Aplastic anemia and gray baby syndrome are adverse effects of which drug?
Chloramphenicol.
Gray baby syndrome: cyanosis decreased RBC and cardiovascular collapse
Resistance to tetracyclines are thought what mechanism?
Efflux pumps
Bacitracin is active against?
Gram positive organisms. Limited to topical use due to nephrotoxicity.
Tooth enamel dysplasia with vestibular toxicity is probably due to which protein synthesis inhibitor?
Tetracyclines (doxycycline)
Which macrolide attains highest tissue levels?
Azithromycin
Which macrolide DOES NOT inhibit cyp p450?
Azithromycin
Which tetracycline can be used against ADH secreting tumors?
Characteristic toxicity?
Demeclocycline
Photosensitivity
What is a known adverse effect of streptogramins after it has been give via IV?
Pain and the arthralgia myalgia syndrome
What is the main resistance mechanism to aminoglycosides? Which 2 aminoglycosides are NOT affected by these?
Inactivating enzymes in the form of: Group transferases
Amikacin and streptomycin
Which aminoglycoside is used as backup drug for N. gonorrhea?
Spectinomycin. Technically only an aminocyclitol related to aminoglycosides.
What is the major AE in the use of streptomycin?
Ototoxicity
Aminoglycosides depend on concentration OR time dependent killing of organisms?
Concentration dependent
With normal renal function, the elimination half-life of aminoglycosides is:
2 - 3 hours
Three reason why aminoglycosides are bacteriocidal
- Block formation of initiation complex
- Cause misreading of the code on the mRNA template
- Inhibit translocation
Which aminoglycosides are more likely associated with auditory dysfunction? Vestibular dysfunction?
Auditory: Kanamycin, Amikacin
Vestibular: Gentamicin, Tobramycin
Side effects of beta lactamase inhibitors
Hypersensitivity and cholestatic jaundice
Clindamycin is NOT effective against?
Gram negative organisms
Narrow spectrum macrolide selective for gram positive aerobes and anaerobes; used in C. difficile colitis
Fidaxomicin
Antibiotic also used in diabetic gastric argh she to its stimulation of motilin receptors
Erythromycin
Which among the adverse effects of aminoglycosides are IRREVERSIBLE? Nephrotoxicity, ototoxicity or neuromuscular blockade.
Nephrotoxicity
How does one decrease the solubility of sulfonamide a in urine?
Acidify the urine
Which sulfonamide is the longest acting?
Sulfadoxine
Sulfamethoxazole
Sulfiaoxazole
Sulfadoxine
Sulfonamides compete with what substance for the enzyme dihydropteroate synthase?
P-aminobenzoic acid
What is the drug of choice for BOTH nocardiosis and pneumocystis pneumonia?
TMP-SMX
What form of nephrotoxicity is seen in aminoglycosides?
Acute tubular necrosis?
Remember: Methicillin interstitial nephritis!
Ketolide structurally related to macrolides with a similar MOA/activity as erythromycin; used in macrolide-resistant strains.
Adverse effects include prolongation of QT interval
Telithromycin
Antibiotic implicated in serotonin syndrome when used in px taking SSRI
Linezolid
Sulfonamide inhibits which enzyme? Trimethoprim?
Sulfonamide: dihydropteroate synthase
Trimethoprim: dihydrofolate reductase
Most common mechanism of resistance to trimethoprim
Production of dihydrofolate reductase that has a reduced affinity for the drug.
Most common adverse effect of quinolones
Gastrointestinal distress.
Other ADEs include rashes, headache, dizziness, insomnia, abnormal LFTs, phototoxicity, tendinitis and tendon rupture.
Bacteriostatic protein synthesis inhibitor given for Vancomycin resistant E. faecium.
Characteristic toxicity?
Quinupristin-dalfopristin
(Streptogramins)
Arthralgia-myalgia syndrome
CYP450 inhibition
What is the treatment for aminoglycoside induced respiratory paralysis?
Calcium, neostigmine and ventilators support.
Which generation of fluroquinolones has the greatest activity against gram negative bacteria?
2nd gen, cipro and ofloxacin
What kind of anemia can be caused by trimethoprim? Ameliorated by what drug?
Megaloblastic anemia; folinic acid
What is the fluoroquinolone that does not need dose adjustment for patients with renal insufficiency?
Moxifloxacin. Eliminated partly by hepatic and biliary mechanisms
What adverse effect is caused by Fluoroquinolones on children?
Arthropathy. It can also cause tendinitis and tendon rupture.
Ototoxicity of aminoglycosides is increase by use of:
Loop diuretics
Aminoglycoside MOST likely to cause allergic skin reaction
Neomycin
The use of sulfonamides in the third trimester of pregnancy can result in?
Kernicterus due to displacement of bilirubin from plasma proteins. Also displaces warfarin and methotrexate!
This quinolone is associated with development of diabetes
Gatifloxacin, currently discontinued
What is the MOA of metronidazole?
Form reactive cytotoxic products to interfere with nucleic acid synthesis. Ferredoxin bioactivates nitro group of metronidazole.
What drug has both disulfiram like reaction with alcohol and potential ion of coumarin anticoagulant effects?
Metronidazole
What is the MOA of mupirocin?
Inhibits protein synthesis by binding to isoleucyl-tRNA synthetase
What do nitrofurantoin, nalidixic acid and merge amine have in common?
Oral drugs RAPIDLY EXCRETED into the urine and act there to suppress bacteria.
What substance inhibits the tubular secretion of penicillins AND fluoroquinolones via the kidney?
Probenecid
