Infectious Disease Drugs 1 Lecture Notes PDF

**Lecture Notes** **INFECTIOUS DISEASE DRUGS 1** **I. Introduction to Antimicrobials** A. [Def] Antimicrobial: any agent that kills or suppresses microorganisms. Antibiotic: a chemical produced by microorganism, has ability to harm others. B. [Selective Toxicity:] ability of drug to kill or su...

**Lecture Notes** **INFECTIOUS DISEASE DRUGS 1** **I. Introduction to Antimicrobials** A. [Def] Antimicrobial: any agent that kills or suppresses microorganisms. Antibiotic: a chemical produced by microorganism, has ability to harm others. B. [Selective Toxicity:] ability of drug to kill or suppress infecting microorganisms without causing injury to host. C. [Use of Antimicrobials] 1\. Treat infection 2\. Prophylactic Use a\. surgery b\. bacterial endocarditis c\. neutropenia D. [Misuses of Antimicrobials] 1\. attempted treatment of untreatable infections 2\. treatment of fever of unknown origin 3\. improper dosage 4\. improper drug for organism 5\. omission of surgical cleaning/drainage E. [Drug Resistance] Microorganisms able to alter function or structure - changes in microbial DNA. 1\. produce drug-metabolizing enzymes 2\. cease active uptake of certain drugs 3\. alter drug-binding sites 4\. produce compounds that antagonize drug actions F. [Types of Antibiotics]: Classified by: 1\. Susceptible organism: gram-pos or gram-neg, anaerobic or aerobic 2\. Narrow spectrum or Broad Spectrum: 3\. Mechanisms of Antimicrobial action a\. Inhibitors of Cell Wall Synthesis 1\. penicillins 2\. cephalosporins 3\. carbapenems 4\. vancomycin b\. Bacteriostatic inhibitors of protein synthesis 1\. tetracyclines 2\. macrolides c\. Bactericidal inhibitors of protein synthesis 1\. aminoglycosides d\. Others 1\. sulfonamides 2\. fluoroquinolones 3\. metronidazole 4\. daptomycin II\. **Inhibitors of Cell Wall Synthesis** Inhibits bacterial cell wall synthesis or activate enzymes that disrupt cell wall. A. [Penicillin] Have beta-lactam ring, some bacteria become resistant, produce beta-lactamase -- penicillinases 1\. [Types of Penicillins] a\. Narrow-spectrum, penicillinase sensitive penicillin G penicillin V/*Pen-Vee K* b\. Narrow-spectrum, penicillinase resistant nafcillin/*Nallpen* dicloxacillin/*Dynapen* oxacillin/*Bactocill* methicillin (obsolete now) c\. Broad-spectrum ampicillin/*Pricipen* amoxicillin/*Amoxil* d\. Extended-spectrum piperacillin/*Pipracil* e\. Penicillin + Beta lactamase inhibitors augmentin: amoxicillin + clavulanic acid unasyn: ampicillin + sulbactam 2\. [Penicillin G] MOA weakens bacterial cell wall by binding to penicillin-binding proteins -\> allows water to enter cell, ruptures cell. IND gram positive bacteria gram negative cocci AE pain at injection site allergic reactions DI aminoglycosides Nursing medic alert bracelets don't mix with aminoglycosides B. [Cephalosporins] 1\. [Types of Cephalosporins]: a\. 1^st^ Generation cefazolin/*Ancef, Kefzol* cephalexin/*Keflex* b\. 2^nd^ Generation cefuroxime/*Ceftin* cefoxitin/*Mefoxin* c\. 3^rd^ Generation ceftriaxone/*Rocephin* cefixime/*Suprax* d\. 4^th^ Generation cefepime/*Maxipime* MOA bind to penicillin-binding proteins and inhibit bacterial cell wall synthesis -\> weakens cell wall, causes lysis and death. IND bacterial infections 1^st^ generation: gram pos -- strept, staph infections, prophy surg 2^nd^ generation: gram neg -- staph also, resp infections, sinus, ear i 3^rd^ generation: broad spectrum, gram neg, reaches CSF 4^th^ generation: strongest, reaches CSF easier AE allergic reactions bleeding thrombophlebitis DI alcohol drugs that promote bleeding Nursing use cautiously in patients with penicillin allergy monitor prothrombin time C. [Carbapenems] 1\. Types a\. imipenem/*Primaxin* b\. meropenem/*Merrem* c\. ertapenem/*Invanz* 2\. [Imipenem/*Primaxin*] MOA binds to penicillin-binding proteins -\> weakens bacterial cell wall -\> lysis, death. Mixed in combo with cilastatin IND gram pos, gram neg bacteria resistant organisms, mixed infections, can reach CSF AE GI effects allergic reactions suprainfections D. [Vancomycin] MOA inhibits cell wall synthesis causing lysis and death. Binds to molecules that serve as precursors for cell wall synthesis. IND serious infections only- gram pos infection with methicillin-resistant Staph antibiotic-associated pseudomembranous colitis: C. difficle AE renal failure ototoxicity flushing/rash thrombophlebitis III\. **Bacteriostatic Inhibitors of Protein Synthesis** Do not cause bacterial cell death - slows microbial growth. A. [Tetracyclines] 1\. Types: tetracycline/*Sumycin* doxycycline/*Vibramycin* minocycline/*Minocin* MOA suppress bacteria growth by inhibiting bacterial protein synthesis. Bind to ribosomal subunits, inhibits binding of transfer RNA to ribosome complex IND broad spectrum against gram pos, gram neg tx of acne tx of infectious disease tx of PUD tx of periodontal disease AE GI irritation discoloration of developing bones and teeth suprainfection hepatotoxicity, renal toxicity photosensitivity DI Metal ions: calcium, iron, magnesium, aluminum and zinc. CI do not use for children \ get inserted -\> weak points -\> cell death IND aerobic gram-negative bacilli -- pseudomonas, E. coli, Klebsiella used in comb with vanco to treat serious infections with gram pos AE ototoxicity nephrotoxicity CI pts with renal disease, elderly DI cephalosporins, vancomycin penicillins ototoxic drugs nephrotoxic drugs Nursing monitor drug levels, peak and trough monitor kidney function: BUN, Cr monitor for signs of ototoxicity do not take for more than 10 days V. **Others** A. [Sulfonamides] 1\. [Types] Sulfasoxazole Sulfadiazine Sulfamethoxazole Trimethoprim + Sulfamethoxazole (Bactrim, Septra) 2\. [Trimethoprim+Sulfamethoxazole (TMP/SMZ)/*Bactrim, Septra*] MOA Both meds disrupt synthesis of folic acid, needed for bacterial biosynthesis of RNA and DNA. IND gram pos, gram neg bacterial infections: UTIs, ear infections, bronchitis protozoal infections: pneumocystis carinii pneumonia AE hypersensitivity reactions hematological effects kernicterus renal damage from crystalluria DI warfarin, dilantin, oral hypoglycemics CI pregnant women near term, breastfeeding children \< 2 months Nursing observe for hypersensitivity reactions avoid sun, wear sunscreen periodic blood work inc fluids B. [Fluoroquinolones] 1\. Types ciprofloxacin/*Cipro* levofloxacin/*Levaquin* norfloxacin/*Noroxin* ofloxacin/*Floxin* gemifloxacin/*Factive* 2\. [Ciprofloxacin/*Cipro*] MOA inhibits bacterial DNA enzyme -\> prevents DNA replication IND broad spectrum, aerobic gram neg, gram pos bacteria infections: respiratory tract, GI, UTI, bones, skin, joint infections prevention of anthrax AE GI effects CNS effects candida infections tendon rupture DI theophylline, warfarin antacids, milk products, iron, zinc C. [Metronidazole/*Flagyl*] MOA taken up by cell, causes DNA strand breakage. IND anaerobic organisms, protozoal infections GI infections GU infections AE CNS effects GI effects DI alcohol warfarin D. [Daptomycin/Cubicin] MOA inserted into cell membrane, causes loss of potassium -\> disrupts membrane, inhibits DNA, RNA synthesis IND gram pos, staph bacteremia, skin infections (MRSA, vanco resistant) AE GI CNS myopathy -- monitor for pain, CPK level DI none --use cautiously with other drugs that affect muscles