Antimicrobials Flashcards
Penicillin G & V
Natural penicillins (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Against gram positive. Bactericidal. G inactivated by gastric acid so can’t be taken orally. V less active by not inactivated by gastric acid. SE convulsions if given IV, <0.1% anaphylaxis
cefradine
1st gen cephalosporin (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Bactericidal. Highly active against gram+. Cross allergy w penicillin 5% of cases
Aztreonam
Monobactam (b lactam)
Notes - Bactericidal. Targets cell wall. Narrow spectrum -> Gram + bacilli, gram - aerobic, enterobacteria, pseudomonas. Used in penicillin & cephalosporin allergy.
Cefaclor
2nd gen cephalosporin (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Bactericidal. activity against gram -. Cross allergy w penicillin 5% of cases
Cefotaxime
3rd gen cephalosporin (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Bactericidal. Activity against gram+ (but less than 1st gen) & strong activity against gram- aerobes (more than 2nd gen) Cross allergy w penicillin 5% of cases
Cefepime
4th gen cephalosporin (b lactam)
Notes- Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Bactericidal. Highly resistant to beta-lactamase. Cross allergy w penicillin 5% of cases
Ceftaroline
5th gen cephalosporin (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Bactericidal. high activity against MRSA. Cross allergy w penicillin 5% of cases
Amoxicillin & ampicillin
Broad spectrum penicillins (b lactam)
Notes - Against Gram negative. Bactericidal. Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Amoxicillin oral, ampicillin lower bioavailability. SE convulsions if given IV, <0.1% anaphylaxis. Ampicillin given with sulbactam (b lactamase inhibitor)
Cloxacillin & floxacillin
b lactamase resistant penicillins (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. Only for methicillin SENSITIVE s. aureus (not MRSA) & some coliforms. Bactericidal. SE convulsions if given IV, <0.1% anaphylaxis
Carbenicillin & ticarcillin & ureidopenicillin
Extended spectrum carboxy-penicillins (b lactam)
Notes - Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. beta lactamase sensitive. Bactericidal. SE convulsions if given IV, <0.1% anaphylaxis
imipenem, meropenem, doripenem, ertapenem
carbapenems (b lactams)
Notes - Bactericidal. Target PBPs which are enzymes for cell wall synthesis which prevents NAG/NAM cross-linking peptide formation & activate autolysins. widest spectrum-> gram + cocci, gram - bacilli ex p. Aeruginosa. anaerobes
Vancomycin
Cell wall inhibitor (glycoprotein)
Notes - Bactericidal. drug of last resort when b lactams don’t work* On reserve for MRSA esp. S.aureus & C.diff* Forms bonds with D-Alanine in PG layer preventing incorporation of NAG/NAM. SE - RED MAN SYNDROME (rate dependent infusion reaction by activating mast cells to release histamine- not mediated by IgE), OTOTOXICITY, NEPHROTOXICITY
Teicoplanin
Cell wall inhibitor (glycoprotein)
Notes - Bactericidal. Longer half life (30h) than vancomycin (4-11h) & fewer S.E. Given IV or intramuscularly
Bacitracin
Cell wall inhibitor
Notes - bactericidal. Inhibits regeneration of lipid carrier of PG so can’t get to cell wall
Cycloserine
Cell wall inhibitor
Notes- Bactericidal. D-Alanine structural analogue so inhibits incorporation. Used for TB
Polymyxin B
Cell membrane inhibitor
Notes- Bactericidal. A detergent that displaces Mg & Ca in cell membrane making it leaky. Has high affinity for phospholipids TOPICAL USE ONLY for gram - (ex pseudomonas & coliforms) bc they have LPS layer which is exposed cell membrane
Erythromycin
1st gen macrolide (inhibits protein synthesis)
Notes - Bacteriostatic @ low doses, bactericidal @ high doses. Bind 50S ribosome and prevent translocation of ribosome along mRNA. SE nausea especially with this drug!!, prolonged QT interval so c/i for heart problems. CYP inhibitor.
Clarithromycin
2nd gen macrolide (inhibits protein synthesis)
Notes - Bacteriostatic @ low doses, bactericidal @ high doses. Bind 50S ribosome and prevent translocation of ribosome along mRNA. SE nausea, prolonged QT interval so c/i for heart problems. CYP inhibitor.
Azithromycin
3rd gen macrolide (inhibits protein synthesis)
Notes - Bacteriostatic @ low doses, bactericidal @ high doses. Bind 50S ribosome and prevent translocation of ribosome along mRNA. Strongest effect for gram negative of all generations. SE nausea, prolonged QT interval so c/i for heart problems. CYP inhibitor.
Doxycycline, tetracycline, minocycline, demeclocycline
Tetracycline (inhibits protein synthesis)
Notes - Bacteriostatic. Bind 30S ribosome and prevent tRNA adding new AA to peptide chain. These are broad spectrum & low cost alternative to penicillins and macrolides! BUT they have a big problem with resistance. SE - photosensitive, teratogenic bc chelator of calcium & metals so c/i in pregnancy & nursing, teeth stains
Gentamycin, streptomycin, amikamycin, tobramycin
Aminoglycosides (inhibits protein synthesis)
Notes - Bactericidal. Bind 30S ribosome and change its shape causing misreading of the mRNA. Mainly active against gram negative aerobes. NEVER first option bc of the extreme SE NEPHROTOXICITY so c/i kidney problem patients, ototoxicity, muscular blockade by displacing calcium from NMJ, blocking Nm receptors & inhibiting ACh release …so c/i myasthenia gravis
Clindamycin
Lincosamide (inhibits protein synthesis)
Notes - Bacteriostatic @ low doses, bactericidal @ high doses. Binds 50S ribosome and prevents aminoacyl translocation so prevents chain elongation. SE - C diff super-infection 2-9 days after therapy starts so c/i elderly
Chloramphenicol
Protein synthesis inhibitor
Notes - Bacteriostatic. Binds 50S and prevents peptide bond formation. Reserved for life-threatening infections caused by BM depression. SE - pancytopenia & GREY BABY SYNDROME
Sulfonamides
PABA analogue (inhibit synthesis & reduction of folate)
Notes - Bacteriostatic. inhibit dehydropteroate synthetase
Linezolid & Tedizolid
Oxazolidinones (inhibit protein synthesis)
Notes - Newest target against ribosomes. Bind 50S and prevent fMET TRNA synthesis. Only for Gram +, good for MRSA & TB multi-resistance & vancomycin resistant enterococcus. SE of linezolid - serotonin syndrome, BM suppression, optic & peripheral neuropathy, lactic acidosis
“Does a “zolid” job except depresses mood, BM, eyes & causes lactic acidosis”
Trimethoprim
DHFR inhibitor (inhibit synthesis & reduction of folate)
Notes - Bacteriostatic. For AEROBIC only
Ciprofloxacin, Levofloxacin, Gemifloxacin
Broad spectrum fluoroquinolones (inhibit DNA synthesis)
Notes - Bactericidal. Inhibit DNA gyrase. SE - torsade du pontes, C. Diff superinfection. cardiac arrhythmias, convulsions, hypoglycemia
Nalidixic acid
Narrow spectrum fluoroquinolone - not fluorinated (inhibit DNA synthesis)
Notes - Bactericidal. Inhibit DNA gyrase. SE - torsade du pontes, C. Diff superinfection. cardiac arrhythmias, convulsions, hypoglycemia
Flagyl
metronidazole (inhibit DNA synthesis)
Notes - Bactericidal. Goes in bacteria & bacterial ferrodoxins activate it into active metabolites - nitro radical anions that chop DNA. for ANAEROBES only. SE - metallic taste, dark urine, stomatitis & glossitis, peripheral neuropathy, teratogenic so c/i pregnancy. Alcohol causes profuse vomiting with it so it can be used as an anti-abuse drug to deter person from drinking. DDI - warfarin*
Rifampicin
RNA polymerase inhibitor - 1st line TB medication
Notes - Bactericidal. Binds beta subunit of bacterial DNA dependent RNA polymerase and inhibits RNA synthesis. Used for TB. SE - HEPATOTOXICITY (must stop if bilirubin increases), ORANGE TEARS/URINE/SWEAT, IMMUNE DYSFUNCTION (thrombocytopenic purpura if intermittent use). CYP inducer
Augmentin
clavulanic acid + amoxicillin
tazobactam
beta lactamase inhibitor - given with beta lactamase sensitive penicillins
Puromycin
Premature termination of peptide chain
TB treatment
Polytherapy
First line:
-> 2 months isoniazid + rifampicin + pyrazinamide + (IF RESISTANT) ethambutol
-> Followed by isoniazid + rifampicin for 4 months
Second line:
-> cycloserine (cell wall inhibitor)
-> streptomycin (aminoglycoside Ab)
-> clarithromycin (macrolide Ab)
-> capreomycin (cyclic peptide)
-> ciprofloxacin (fluoroquinolone)
XDR-TB - resistant to everything
MDR-TB - resistant to isoniazid & rifampicin
Isoniazid
1st line TB medication
Notes - inhibits mycolic acid synthesis in cell wall. SE hepatitis, peripheral neuropathy, pyridoxine (Vit B6) deficit, agranulocytosis, psychosis (Rare). CYP inhibitor
Ethambutol
1st line TB medication
Notes - inhibits mycolic acid movement to cell wall and inhibits RNA synthesis. SE - optic neuritis (colour deteriorates first)
Pyrazinamide
1st line TB medication
Notes - inhibits FAS. SE - hepatitis, athralgia, hyperuricemia. c/i in GOUT
Gram Positive AEROBES
Cocci - staph, strep, entero
Rods - Bacillus, listeria, nocardia
Gram Positive ANAEROBES
Rods - C.diff, actinomyces
Gram Neg AEROBES
Cocci - Neisseria
Rods - Lactose fermenters (e. coli, klebsiella), non-lactose fermenters (salmonella, shigella), pseudomonas, vibrio, Hemophilus
Misc. bacteria
Chlamydia, mycoplasma, legionella, helicobacter
