Test Questions on Therapeutics ID Bergman – Flashcards

• Beta Lactamase Producing
• Alteration of PBPs (MRSA)
• Modification of outer cell membrane (Most G-)

1. Nafcillin (primarily hepatic)
2. Oxacillin (renal and hepatic)

• Allergic Rxns

Anaphylaxis (can't rechallenge with another beta lactam)

Urticaria (hives)

Drug Fever

• GI (N/V/D - occurs with PO classes)
• Hematologic
• Neurologic (seizures)
  

1. Beta Lactamases
2. Alteration of PBPs
3. Outer cell membranes changes

Renal

Exception:

Ceftriaxone (biliary)

Cefoperazone

• Allergic Rxns

Anaphylaxis

Urticaria

Drug Fever

• Hematologic
• Neurologic
• Disulfiram-Like Reactions (MTT side chain only)

Cefotetan, cefamandole, cefmetazole, cefoperazone, moxalactam

Flushing, Vomiting - with concomitant alcohol consumption

Increased INR

• Decreased penetration (G- bacilli)
• Altered PBPs
• Production of broad spectrum Beta Lactamases

Imipenem

• It is susceptible to dehydropeptidase 1 of the renal brush border
• Cilastatin is a DHP 1 inhibitor

• Diarrhea

high risk of C. difficile

• Allergic reactions

Anaphylaxis, urticaria, drug fever

Cross reaction with penicillins is higher than cephalosporins

• Seizures (Imipenem > all other beta lactams, due to accumulation of cilastatin)

Weakly Immunogenic (due to one ring)

People with PCN allergy can use aztreonam

• Binds irreversibly to 30S bacterial ribosomal subunit --> interference of genetic code and inhibition of protein synthesis
• Bactericidal

• Ribosomal mutation --> drug cannot bind to 30S subunit
• Reduce transport into cell
• Plasmid-mediated aminoglycoside-modifying enzymes

Renal

Good for G- UTIs

• Improves peak to MIC ratio and maximizes concentration dependent bactericidal activity
• Takes advantage of post-antibiotic effect
• Gives kidneys time to recover so possibly less nephrotoxicity
• Less potential for resistance
• Lower cost of supplies at nursing time

G+ Infections

MSSA

Enterococci

Aminoglycosides are Mean O'l Guys!

• Nephrotoxicity
• Ototoxicity (vestibular and auditory)
• Neuromuscular Blockade (if infused too quickly)

• Structural analoge of p-aminobenzoic acid (PABA), the building block used by bacteria to make dihydrofolic acid
• Dihydrofolic acid is used to make folic acid, which is used for nucleotide synthesis
• Sulfamethoxazole competitively inhibits bacterial dihydropteroate synthetase, an enzyme critical for folic acid biosynthesis

• Competitively inhibits dihydrofolate reductase, inhibiting conversion of dihydrofolic acid to tetrahydrofolic acid, the metabolically active cofactor for synthesis of purines, thymies, and DNA

Renal

;

Good for UTIs

• Hypersensitivity reactions
• Crystallization in the Kidneys - counsel patients to take with water
• Hematologic - bone marrow suppression at high doses

• Binds reversibly to 30S bacterial ribosomal subunit
• Blocks attachment of tRNA to an acceptor site on the mRNA ribosomal complex

• Respiratory Infections
• Genital Infections
• Skin Infections

• Photosensitivity
• Discoloration of Developing Teeth - CI ; 8 yo, pregnant, nursing mothers
• Esophageal Ulceration

• A glycylcycline antibiotic
• Similar MOA as tetracyclines (inhibits 30S ribosomal subunit)
• 5X binding affinity -- overcomes resistance mechanisms (ribosomal and efflux pumps)

• Staph. aureus (inclusing MRSA)
• Enterococcus (including VRE, excluding Proteus mirabilis)
• Strep. pneumoniae (including PRSP)
• Enterics (including ESBLs)
• Non-Enterics (excluding P. aeruginosa)
• Respiratory G-
• Anaerobes
• Atypicals

• Point mutations
• Decrease outer membrane permeability

Ciprofloxacin and Levofloxacin are used for bacteremia and UTIs

Moxifloxacin is NOT used for UTIs

Gemifloxacin is used for respiratory tract infections ONLY

• CNS effects (dizziness)
• Arthropathy
• Tendonitis/Tendon Rupture (Black Box Warning for kids - inhibits cartilage development)
• QT Interval Prolongation

• CI when taking both at same moment in time
• Separate Quinolone and Iron supplement
• Iron supplement 1 hr before Quinolone or 2 hours after Quinolone
• Some say 4 before or 4 after

Lincosamide Antibiotic

Inhibits bacterial protein synthesis by binding to 50S ribosomal subunit

Hepatically Metabolized

No dosage adjustment for renal impairment

False

Only patients that are hepatically retarded need dosage adjustments, b/c it is hepatically metabolized

• Diarrhea
• GI upset

• Enters cell by passive diffusion and is activated by reductive processes
• This produces short-lived metabolites that damage bacterial DNA and subsequently causes cell death

• Hepatically metabolized
• No dosage adjustment unless severe kidney failure

• CNS effects
• GI upset
• Metallic taste
• Disulfiram-Like Reaction (possible but not likely - don't use with alcohol)

• Binds reversibly to 50S bacterial ribosomal subunit
• Inhibits protein synthesis

• Aplastic anemia (irreversible)
• Bone marrow suppression (reversible)
• Gray Baby Syndrome (primarily neonates)

• Nephrotoxicity - not as bad as aminoglycosides
• Drug Fever
• Infusion-Related Side Effects

"Red Man" Syndrome

Hypotension

• Metabolized to several active major metabolites
• Fecal excretion constitutes the main elimination route for both parent drugs and their metabolites

• Enterococcus faecium (VRE), not E. faecalis
• Staph. aureus
• Strep. pyogenes

• Inflammation at infusion site
• Arthralgia/myalgia

Oxazolidine Antibiotic

Binds to 23S rRNA of the 50S subunit --> prevents formation of a functional 70S initiation complex

-static against Staph.

-cidal against Strep.

• Renal clearnace is low and suggests net tubular reabsorption
• Mainly Non-Renal

MRSA

VRE

Strep. pneumoniae

Cyclic Lipopeptide Antibiotic

• Inserts lipophilic tail into cytoplasmic membrane --> forms a channel that causes depolarization
• Efflux of K+ and perhaps other ions inhibits macromolecular synthesis and leads to cell death
• Kills bacteria but leaves cell wall intact which may potentially lead to toxins being suddenly released into the system

Aerobic G+

MRSA

VRE

Myopathy

Not a selective agent and can target cell membranes of skeletal muscles

Lipoglycopeptide

• Combines mechanisms of both vancomycin (glycopeptide) and daptomycin (cyclic lipopeptide)
• Works on cell wall and cell membrane
• Bactericidal

Nephrotoxicity

Black Box Warning: Birth Defects