Antimicrobial Drugs

Antimicrobial Drugs

1. Goal: Elminate microbes

   • Need to identify/understand microbe
   • Specificity for the pathogen/ not normal microflora
   • Understand and monitor drug resistance
   • Understand host factors

2. Mechanisms of action:

   • Inhibition of cell wall synthesis
   • Inhibition of protein synthesis
   • Interferance with nucleic acid synthesis
   • Inhibition of cell metabolism
   • Disruption of cell membrane permeability
   • Interruption of viral enzymes

3. Antibiotics

   • Beta-Lactam Antibiotics
     • Inhibit cell wall synthesis- bind to specific protein w/i pedtidoglycan layer- lysis cell causing death
     • Penicillins
       • Many people allergic to
       • Kill gram+ bacteria
         • Staphylcoccus
       • Subdivided into four grps based on chemical structure and type of bacteria they kill
         • Natural Penicillins
           • pneumonia, menigitis, pharyngitis, syphilis, and infectious encarditis, anthrax, tetanus, gas gangrene, rheumatic fever, bacterial endocarditis
         • Penicillinase-resistant penicillins
           • Kill bacteria with beta-lactamase enzyme- primarily tx penicillin resistant staph
         • Aminopenicilins
           • Useful for same as natural penicillins, but also gram- bacteria
             • TX bacterial menigitis, otitis media, septicemia, gonorrhea, and sinusitis
         • Extended-spectrum penicillins
           • Kill gram- species
             • Pseudomonas, Enterobacter, and Proteus
           • Aminopenillins
           • Carboxypenicillins
           • Ureidopenicillins
       • Many drugs have developed resistance to
       • Compete with NSAIDS and decrease effectiveness of oral contraceptives and warfarin
   • Cephalosporins
     • Similar to penicillins but have broader uses
     • Subdivided by generations
       • 1st
         • Cefazolin, cephalexin, cefadroxil, cephradine
           • Streptococcus spp. staphylococcus aureus
             • Skin, soft tissue, urinary, and respiratory infections,
       • 2nd
         • Cefuroxime, cefuroxime axetil, ceforetan, cefoxitin, cefprozil, cefmetazole, loracarbef
           • TX sinusitis, otitis, resp. tract infections, prophylaxis in colorectal surgery
       • Third
         • Cefotaxime, ceftriaxone, cefdinir, cefditoren, ceftibuten, cefpodoxime, ceftizoxime, cefoperaxone, ceftazidime
           • Tx septic pt. and immunocompromised pts
       • Fourth
         • Cefepime
           • Tx nosocomiall infections that are resistant to other antibiotics
     • Pt. should abstain from alcohol and aspirin while using
   • Carbapenems A.K.A Extended spectrum beta-lactamase inhibitor
     • Imipenem, meropenem, ertapenem, doripenem, panipenem, and biapenem
       • Kill broader spectrum than penicillins
     • Avoid using with C.difficile and mixing with other I.V mmemedications
   • Monobactams
     • Azteonam
       • Tx gram- rods: UTI's dermal infections, septicemia, intra abdominal and gynecologic infections
   • Beta-Lactamase Inhibitors
     • Have limited effects on bacteria but help Beta-lactam drugs work
     • Some bacteria have also become resistant to this
   • sulfonamides
     • Targets folic acid synthesis cutting down on nutrient supply
       • TX UTIs, also used on burns, and malaria
     • Use caution when dealing w/ pts. w/ diabetes and kidney problems, and pts. with frequent sun exposure
   • Tetracyclines
     • Derived from soil mold
       • Tetracycline, demeclocycline, oxytetracycline
     • Semi-synthesized
       • Doxycycline, minocyline
     • Broad-spectrum: gram + and-
     • Glycylcyclines
     • TX endocervical, rectal, urethral, acne, pelivic inflammatory disease, STDS and traveler's diarrhea
   • Amnioglcyosides
     • Mostly gram- but some gram+
     • Small therapeutic window with severe adverse effects
     • Narrow spectrum
     • Poor oral absorption: used to clean colon
   • Macrolides
     • Erythromoycin
       • Safest, but many drug interaction and resistance- Not used very widely
       • Azithromycin, clarithromycin, dirithromycin, roxithromycin telithromycin
     • Broad spectrum
     • TX gram+ aerobic cocci and bacilli
   • Quinolones and Fluoroquinolones
     • Ciprofloxacin, norfloxacin, levofloxacin, gemifloxacin, moxifloxacin, ofloxacin
     • TX UTI's, STDs, GI, abdominal, respiratory, bone and joint, and soft-tissue infections
       • Active against gram+ and few gram-
   • Lincosamides
     • Has been replaced by clindamycin
   • Vancomyocin
     • Used to tx severe infections
     • Only use IV route, no oral route

4. Antitubercular drugs

   • Isoniazid, ethambutol, ethionamide, pyrazinamide, rifampin, streptomycin

5. Antiviral medications

   • Non-retroviral agents
     • Anti-herpesvirus, anti-influenza, anti-hepatitis agens
   • Antiretroviral agents
     • Nucleoside reverse transcriptase inhibitors (NRTIs), Non-nuceloside transcriptase inhibitors (NNRTIs), Protease inhibitors, entry inhibitors, integrase strand transfer inhibitors

6. Antifungal medications

   • Systemic antifungals
   • Azole antifungals
   • Topical medications that tx skin and mucous membranes

7. Antiparasitic Agents

   • Protozoal agents
   • Antiprotozoal agents
   • Anthelmintic agents