Antimicrobials Flashcards
Aminoglycosides
Aerobic and facultative gram negative bacteria
Inhibits prtoein synthesis at the 30s subunit Lysis of cell envelope
DOC: enterobacter, E. coli, K. pneumoniae, Proteus, Serratia, P. aeruginosa
PK:
- Not absorbed in the GIT (administered parenterally)
- Low protein binding High concentration in the renal cortex and inner ear
- Significant post-antibiotic effect
- Once-a-day because it is concentration dependent
ADRs:
- Ototoxicity
- Nephrotoxicity
- Neurotoxicity
- Hypersensitivity
Virulence factor and MOT of Pseudomonas aeruginosa
Endotoxin
Direct contact
Beta Lactams: Enumerate Penicillinase-resistant penicillins
Nafcilin
Methicillin
Oxacillin
Cloxacillin
Flucloxacillin
ADR of Nafcillin
Neutropenia
ADR of Methicllin
Nephrotoxicity
Indications:
- Pneumonia/bronchopnuemonia for children 6 months to 3 years old
- Gram positive streptococcus
- Gram negative H. influenzae
- UTI
- Salmonella infection (typhoid fever, carriers)
Aminopenicillins
- ampicillin
- amoxicillin
- bacampicillin
Drug of choice for Shigella
Ampicillin
Extended Spectrum Penicillins
- Targets grame negative bacteria
- Pseudomonal penicillins
- Carbenicillin
- Ticarcillin
- Mezlocillin
- Piperacillin (Tazocin)
- Azlocillin
Penicillin
Spectrum: gram positive (mainly), extended spectrum PCNs also target gram negatives
MOA:
- binds to PBPs
- analogs of the D-al-D-ala terminal sequence
- inhibits transpeptidase enzyme
PK:
- Poor oral absorption
- acid labile (PCN G, Methicillin)
- amoxicillin: good absorption
- Nafcillin: biliary clearance
Clearance of Nafcillin
Biliary Clearance
Probenecid and Penicllin drug interaction
Probenecid inhibits secretion of PCN
ADR of Nafcillin
Nafcillin: neutropenia
ADR of Oxacillin
Hepatitis
ADR of Methicillin
Interstitial nephritis
First generation cephalosporins, spectrum, indications
Cephalexin, Cefazolin
Spectrum: Staphyloccous, streptococci
Indications: UTI, minor staph infections, minor cellulitis or tissue abscess
Second generation cephalosporins, spectrum of activity
Cefuroxime
Cefaclor
Cefoxitin
Spectrum: Gram positive and gram negative
Indicatoions: mixed infections such as diabetic foot ulcers and asphyxiation pneumonia
Cefuroxime is effective for
Community acquired pneumonia
Crosses BBB
Penicillin effective againts Bacteroides
Cefoxitin
Penicllin effective against H. influenzae
Cefamandole
Cefuroxime
Cefaclor
Third generation ceophalosporins, spectrum, indications
Aerobic gram negative organisms
- aerobic gram negative bacterial meningitis
- biliary tract infection
Aztreonam: spectrum of activity, MOA, advantage over aminoglycosides and cephalosporins, PK
MOA: Binds to PBPs, interferes with cell wall synthesis
Spectrum:
- Only for aerobic gram negtaive rods, including pseudomonas
- beta lactamas resistant gram negative rods
PK: not absorbed orally
Advantages:
- not nephrotoxic
- remains bactericidal under anaerobic conditions
- safe to those with anaphylactic reactions to penicillin
Carbapenems, MOA, spectrum
Carbapenems:
- Imipenem
- meropenem
- Ertapenem
MOA:
- Bind to PBPs
- PBP1: bacterial wall’s constant diameter
- PBP2: extends the bacterial cell wall in any direction
- Resistant to most beta lactamases
Spectrum: Broad
- Grame positive cocci
- Gram negative rods
- Anaerobes
Carbapenems are inactivated by
Renal dihydropeptidases –> low renal concetration
Carbapenem which inhibits renal dihydropeptidase
Cilastatin
Beta lactamas inhibitors with negligible antibacterial activity
- Clavulanic acid
- Sulbactam
- Tazobactam
Indications and adverse effects of chloramphenicol
Indications:
- H. influenzae
- N. meningitides
- Bacteroides
- Salmonella
ADRs:
- Bone marrow depression: aplastic anemia
- anemia
- Gray baby syndrome
- GIT effects
Lincosamides, Indications, ADRs
Lincosamides:
- Lincomycin
- Clindamycin
Indications:
- anaerobes
- gram positive infections (clindamycin)
- osteomyelitis
- acne
ADRs:
- Pseudomembranous colitis
- superinfection
Metronidazole, spectrum of activity, ADRs
Indications:
- effective ageainst amoeba
- amoeba-like organisms
- anaerobic infections (gas gangrene)
- E. histolytica
- trichomonas
- giardia lambdia
- balantidum
ADRs: disulfiram-like ractions
Macrolides, spectrum of activity, indications, ADRs
Spectrum: gram (+) aerobic bacteria, some gram (-), atypical agents that cause atypical pneumonia
Indications:
- DOC for Campylobacter, mycoplasma, or Legionella
- alterantive to beta lactam allergy
ADRs: Liver toxicity (erythromycin estolate)
Erythromycin, absorption, excretion, adverse drug reactions
Absorption: duodenum, impeded by food
Excretion: biliary excretion, not removed by dialysis
ADRs: intestinal gastric irritation, nausea, vomiting, diarrhea, GI intolerance
Clarythromycin, advantage over erythromycin, spectrum of activity
Lower incidence of GI intolerance
active against mycobacterium avium complex, m. leprae, toxoplasma gondii, H. influenza
Azithromycin, administration, indication
Administration: Once a day dosing, given for 3-5 days
Indication:
- prohylaxis of Mycobacterium avium intracellulare complex,
- Chlamydia sp.
Quinolones, mechanism and mode of action, spectrum of acitivity, ADRs, contraindication
Quinolones:
- Ciprofloxacin
- levofloxacin
MOA: inhibits DNA gyrase and topoisomerase IV, bactericidal
Spectrum: broad spectrum
ADR: arthropathy
Contrainidications: not for children less than 18 y/o
Sulfonamides, MOA, Indications, Contraindications
MOA: inhibits folic acid synthesis
Indications:
- uncomplicated UTI
- malaria
- toxoplasmosis
- pneumocustis carinii in AIDS
Contraindications:
- Infants less than 2 months old: kernicterus
- pregnant lactating mothers: neural tube defects
Tetracyclines, Spectrum of activity, Indications, ADRs, Contraindications
Spectrum: Broad
DOC: mycoplasma, chlamydia, rickettsia, vibrios
Secondary use: syphilis, respiratory infections, leptospirosis, acne
ADRs:
- GIT
- photosensitivity
- hepatotoxicity
- nephrotoxicity
- minocycline: vestibular toxicity
Vancomycin, MOA, spectrum of activity, indications, ADRs
MOA: inhibits synthesis of bacterial cell wall by inhibiting transglycosidase, binds to D-ala-d-ala terminus
Spectrum: narrow: only on cocci
Indications: DOC for serious drug resistant gram positive organisms
ADRs:
- Thrombophlebitis
- Nephrotoxic
- Ototoxic
- Hypersensitivity: red man syndrome, hypotension, pain and spasm syndrome
Main clinical use for streptogramins
Treatment of vancomycin-resistant strains of enterococcus faecium
Bacitracin is good against __
Staphylococcus aureus
Urinary antiseptics
Nitrofurantoin
Methenamine hippurate: acidifies urine and releases formaldehyde
Phenazopyridine
Sulfonamides are primarily metablized by what mechanism
Acetylation
The most important reason for limited clinical use of chloramphenicol
Potential for bone marrow suppression
Tetracyclines are avoided in pregnancy because of
Enamel dysplasia in the offspring
Which antimicrobial group has neuromuscular blocking actions
Aminoglycosides
Which anti-TB drug causes hyperuricemia
Pyrazinamide
Which antimalarial is ototoxic and contrainidicated in 3rd trimester of pregnancy
Quinine
