Antibacterial Antibiotics Flashcards
Interfere with last step of cell wall synthesis (transpeptidation or cross
linking)
Penicillins (Penicillum notatum)
Beta lactam attached to:
thiazolidine ring, Nucleus: 6 aminopenicillanic acid
Beta lactamase Inhibitors
(Clavulanic acid, sulbactam, tazobactam)
No antibacterial activity. They inactivate beta lactamases
Beta lactamase Inhibitors (Clavulanic acid, sulbactam, tazobactam)
The beta lactam ring is not fused to another ring, no cross sensitivity with penicillin
Monobactam
magic bullet for Pseudomonas
Aztreonam
Thienamycin, Meropenem, Imipenem (cleaved by dihydropeptidase; cilastatin)
Carbapenems
Drugs under Natural Penicillins
Penicillin G (Benzylpenicillin) PO, IV, IM(Procaine and Benzathine) Use: RHD and Syphilis Penicillin V (Phenoxymethylpenicillin) PO
Drugs under Penicillinase Resistant/Antistaphylococcal Penicillins/Narrow Spectrum
Methicillin (2,6 dimethoxyphenylpenicillin) Prototype; off the market (interstitial nephritis) Nafcillin (2 ethocy 1 phenylpenicillin) Isoxazolyl Penicillins (Oxacillin, Cloxacillin,Dicloxacillin best absorbed orally)
Drugs under Aminopenicillins/Broad Spectrum
Ampicillin (Parenteral, poor GI absorption) Prodrugs: Hetacillin, Bacampicillin, Cyclacillin
Amoxicillin (PO)
Drugs under Extended Spectrum/Anti Pseudomonal Penicillins
Carboxypenicillins (Carbenicillin, Ticarcillin)
Ureidopenicillins (Piperacillin most potent, Azlocillin, Mezlocillin)
only for G-
Gramicidin (S. Brevis)
only for G+ ; MOA: Alter cell membrane permeability; Polymixin B and Colostin (Polymixin E)
Polymyxin (B. Polymyxa)
nephrotoxic (not for IV)
Bacitracin (B. Subtilis)
DOC for Pseudomembranous colitis and MPSA
Vancomycin (S. Orientalis)
Only IV (not orally absorbed);
Vancomycin (S. Orientalis)
Adverse effects of Vancomycin
Flushing (Red Man Syndrome)
Classes that binds to 30s subunit
AMINOGLYCOSIDES, TETRACYCLINES
Classes that binds to 50s subunit
MACROLIDES, LINCOSAMIDES, CHLORAMPHENICOL
Drugs under Aminoglycosides
(Streptomycin, Gentamicin, Netilmicin, Neomycin, Tobramycin, Amikacin from Kanamycin A)
Drugs under Tetracyclines
(Doxycycline, Minocycline, Tetracycline, Demeclocycline)
ingestion of expired tetracycline
Fanconi like syndrome
Broadest spectrum antibiotic
TETRACYCLINES (Doxycycline, Minocycline, Tetracycline, Demeclocycline)
Adverse effects of tetracyclines
Gastric discomfort, deposition in the bones and primary dentition causing discoloration and hypoplasia of the teeth and a temporary stunting of growth, hepatotoxicity, phototoxicity (demeclocycline), vestibular problems (minocycline)
IV (not absorbed orally) except neomycin (topical and oral only)
AMINOGLYCOSIDES (Streptomycin, Gentamicin, Netilmicin, Neomycin, Tobramycin, Amikacin from Kanamycin A)
Streptomyces (mycin) | Micromonospora (micin)
AMINOGLYCOSIDES
Adverse effects of aminoglycosides
Allergic reactions, Muscle relaxation, Incompatile with B lactams, Nephrotoxic (neomycin)
Ototoxic (streptomycin), G cocci only
Common chemical characteristics of MACROLIDES
A large lactone ring, A ketone group, A glycosidically linked amino sugar
Alternative/DOC for Pen G allergy and Legionnaire’s disease
Erythromycin (Ilotycin) S. erythreus
Used with Omeprazole or Lansoprazole (H.pylori eradication), more potent for strep and staph
Clarithromycin
For nongonococcal urethritis (Chlamydia, LRTI, PID, pharyngitis, Legionnaire’s)
Azithromycin, OD
For typhoid fever (Ceftriaxone new DOC), meningococcal infections and H.influenza infections in cephalosporin allergic patients, anaerobic infections
CHLORAMPHENICOL (S. venezuelae)
For abdominal and female genitourinary tract infections caused by B. fragilis
LINCOSAMIDES (Clindamycin) Streptomyces lincolnensis
Esters (eg. stearate, estolate, and ethylsuccinate) have improved acid stability
Erythromycin (Ilotycin) S. erythreus
Adverse effects of Erythromycin (Ilotycin)
epigastric distress, cholestatic jaundice (estolate form of erythromycin)
40 to 68 hours half life is prolonged because of extensive tissue sequestration and binding (↑Vd)
Azithromycin, OD
Sulfur containing; Resemble sulfonamides in antibacterial spectrum and biochemical MOA
LINCOSAMIDES (Clindamycin) Streptomyces lincolnensis
Adverse effects of Lincosamides
Pseudomembranous colitis, rash
DOC for Pseudomembranous colitis, rash
Vancomycin
Bone marrow suppression
(dose related)
Aplastic anemia
(non dose related)
Gray Baby Syndrome
(neonates)
Used topically for impetigo, eczema, staphylococcal and beta hemolytic streptococcal infections
MUPIROCIN (Pseudomonas fluorescens)
topical treatment of burns
Nitrofurazone
DOC for E. Histolytica, G. Lambia, Trichomonas vaginalis
Metronidazole
Treatment of Chagas’ disease/American Sleeping sickness (Trypanosoma cruzi)
Nifurtimox
Vector: reduviid bug/kissing bug
Nifurtimox
diarrhea (SPEcKs;) CI: Alcohol
Furazolidone (PO)
Urinary antiseptic
Nitrofurantoin
Metallic taste, Disulfiram like effect
Metronidazole
DOC for leprosy (Test: G6PD)
Dapsone
Chloroquine resistant malaria
Quinine + pyrimethamine + sulfadoxime (Fansidar®)
DOC for Pneumocystis carinii
Bactrim; alternative drug: Pentamidine (aromatic diamide)
Burn therapy
Silver sulfadiazine and Mafenide (Flammazine®)
Conjunctivitis
Sodium sulfacetamide
Patterned after nalidixic acid (introduced for the treatment of UTI and URTI)
QUINOLONES
Mechanism of Action of MUPIROCIN (Pseudomonas fluorescens)
Inhibition of RNA and DNA synthesis
Mechanism of Action of MUPIROCIN (Pseudomonas fluorescens)
Inhibition of RNA and DNA synthesis
Mechanism of Action of QUINOLONES
Inhibits DNA gyrase (topoisomerase II)
Mechanism of Action of SULFONAMIDES
Compete with PABA for dihydropteroate synthetase—prevents synthesis of folic acid
adverse effects of QUINOLONES
Diarrhea, nausea, headache, dizziness, nephrotoxicity, phototoxicity
adverse effects of SULFONAMIDES
Crystalluria, Steven Johnson Syndrome, Kernicterus, Anemia
have enhanced antibacterial activity
Fluoroquinolones
most potent
Ciprofloxacin
anti pseudomonal
Norfloxacin
Chelates with metals
QUINOLONES
(essential for antibacterial activity)
1,4 dihydro 4 oxo 3 pyridinecarboxylic acid moiety
Sulfonamides are usually used with
dihydrofolate reductase inhibitors (e.g Trimethoprim)
studied a bright dye, Prontosil (metabolized in vivo to sulfanilamide active)
Gerard Domagk