Antibiotic Classification & Indications

Inhibits Cell Wall Synthesis Penicillins (bactericidal: blocks cross linking via competitive inhibition of the transpeptidase enzyme) Class/Mechanism Drugs Indications (**Drug of Choice) Toxicity Penicillin Penicillin G Aqueous penicillin G Procaine penicillin G Benzathine penicillin G Penicillin V Strep. pyogenes (Grp.A)** Step. agalactiae (Grp.B)** C. perfringens(Bacilli)** Hypersensitivity reaction Hemolytic anemia Aminopenicillins Ampicillin Amoxicillin Above + ↑ Gram-negative: E. faecalis** E. Coli**  Above Penicillinase-resistant-penicillins Methicillin Nafcillin Oxacillin Cloxacillin Dicloxacillin Above + PCNase-producingStaph. aureus Above + Interstitial nephritis Antipseudomonal penicillins Carbenicillin Ticarcillin Piperacillin Above + Pseudomonas aeruginosa**  Above Cephalosporins (bactericidal: inhibits bacterial cell wall synthesis via competitive inhibition of the transpeptidase enzyme) 1st generation  Cefazolin Cephalexin Staph. aureus** Staph. epidermidis** Some Gram-negatives: E. Coli Klebsiella Allergic reaction Coombs-positive anemia (3%) 2nd generation Cefoxitin Cefaclor Cefuroxime Above + ↑ Gram-negative Allergic Reaction ETOH Disulfiram reaction 3rd generation Ceftriaxone Cefotaxime Ceftazidime Cefepime (4th generation) Above + ↑ Gram-negative Pseudomonas Allergic Reaction ETOH Disulfiram reaction Other Cell Wall Inhibitors Vancomycin  (bactericidal: disrupts peptioglycan cross-linkage)  Vancomycin MRSA** PCN/Ceph allegies** S. aureus S. epidermidis Red man syndrome Nephrotoxicity Ototoxicity Beta-lactamase Inhibitors  (bactericidal: blocking cross linking) Clavulanic Acid Sulbactam Tazobactam S aureus** S epidermis** E.Coli** Klebsiella** Hypersensitivity Reaction Hemolytic anemia Carbapenems Imipenem (+ cilastatin) Meropenem Doripenem Ertapenem Broadest activity of any antibiotic (except MRSA, Mycoplasma) Aztreonam Aztreonam Gram-negative rods Aerobes Hospital-acquired infections Polymyxins Polymyxin B Polymyxin E Topical Gram-negative infections Bacitracin Bacitracin Topical Gram-positive infections Protein Synthesis Inhibition Anti-30S ribosomal subunit Aminoglycosides (bactericidal: irreversible binding to 30S)  Gentamicin Neomycin Amikacin Tobramycin Streptomycin Aerobic Gram-negatives Enterobacteriaceae Pseudomonas Nephrotoxicity Ototoxicity Tetracyclines (bacteriostatic: blocks tRNA) Tetracycline Doxycycline Minocycline Demeclocycline Rickettsia Mycoplasma Spirochetes (Lyme's disease) Hepatotoxicity Tooth discoloration Impaired growth Avoid in children < 12 years of age Anti-50S ribosomal subunit Macrolides (bacteriostatic: reversibly binds 50S) Erythromycin Azithromycin Clarithromycin Streptococcus H. influenzae Mycoplamsa pneumonia Coumadin Interaction (cytochrome P450) Chloramphenicol (bacteriostatic) Chloramphenicol H influenzae Bacterial Meningitis Brain absces Aplastic Anemia Gray Baby Syndrome Lincosamide (bacteriostatic: inhibits peptidyl transferase by interfering with amino acyl-tRNA complex) Clindamycin Bacteroides fragilis S aureus Coagulase-negative Staph & Strep Excellent Bone Penetration Pseudomembranous colitis Hypersensitivity Reaction Linezolid (variable) Linezolid Resistant Gram-positives Streptogramins Quinupristin Dalfopristin VRE GAS and S. aureus skin infections DNA Synthesis Inhibitors Fluoroquinolones (bactericidal: inhibit DNA gyrase enzyme, inhibiting DNA synthesis) 1st generation   Nalidixic acid Steptococcus Mycoplasma Aerobic Gram + Phototoxicity Achilles tendon rupture Impaired fracture healing  2nd generation Ciprofloxacin Norfloxacin Enoxacin Ofloxacin Levofloxacin As Above +Pseudomonas as above 3rd generation Gatifloxacin As above + Gram-positives as above 4th generation Moxifloxacin Gemifloxacin As above + Gram-positives + anaerobes as above Other DNA Inhibitors Metronidazole (bacteridical: metabolic biproducts disrupt DNA) Metronidazole (Flagyl) Anaerobics Seizures Crebelar dysfunction ETOH disulfram reaction RNA Synthesis Inhibitors Rifampin (bactericidal: inhibits RNA transcription by inhibiting RNA polymerase) Rifampin Staphylococcus Mycobacterium (TB)  Body fluid discoloration Hepatoxicity (with INH) Mycolic Acids Synthesis Inhibitors Isoniazid Isoniazidz TB Latent TB Folic acid Synthesis Inhibitors Trimethoprim/Sulfonamides (bacteriostatic: inhibition with PABA) Trimethoprim/Sulfamethoxazole (SMX) Sulfisoxazole Sulfadiazine UTI organisms Proteus Enterobacter Thrombocytopenia Avoid in third trimester of pregnancy Pyrimethamine Pyrimethamine Malaria T. gondii