Antibiotic Pharmacotherapy Flashcards
Bactericidal
Antibacterial drug that kills microorganisms
Bacterostatic
Antibacterial drug that inhibits microorganism growth
Superinfection
A new or secondary infection that occurs during antimicrobial therapy of a primary infection
- d/t too large of a dose or inhibition of normal flora within the body
Antibiotic Combination Therapy
2+ drugs
- Synergistic effect
- Prevent emergence of drug resistant organisms
- Tx immunosuppressed pts
Empiric Therapy
Tx of an infection prior to identification of organisms via culture
- Broad spectrum antibiotic
- If necessary, change agent after culture & sensitivity results are obtained
Antibiotic MOA’s
Act on any structures unique to bacteria
MOA: Penicillin, Cephalosporin, Vancomycin
inhibition of bacterial cell wall synthesis/activation of enzymes that disrupt bacterial cell walls
MOA: Aminoglycocides, Clindamycin, Erythromycin, Tetracyclines
Inhibition of protein synthesis by bacterial or production of abnormal bacterial proteins
- Bind irreversibly w/ bacterial ribosomes -> cannot synthesize proteins
MOA: Anti-fungals
Disruption of microbial cell membranes
MOA: Fluoroquinolones & Anti-virals (e.g. Rifampin)
Inhibition of organism production by interfering with nucleic acid synthesis
MOA: Sulfonamides & Trimethoprim
Inhibition of cell metabolism & growth
Indications for Prophylactic Therapy
- Group A strep infections
- Bacterial endocarditis in pt’s with CVD having dental, surgical, or other invasive procedures
- TB-INH
- Peri-operative infections in high-risk pt’s
- STD’s (gonorrhea, syphilis, chlamydia) after exposure has occurred
- Recurrent UTI in premenopausal or sexually active women
Antimicrobial Dosing & Administration
- Individualized to each pt*
- Avg. duration of therapy for acute infections = 7-10 days (48-72 hrs. if febrile and asymptomatic)
- Schedule dose at even intervals
- Take most on empty stomach (1 hr. before or 2 hrs. after meal) w/ glass of water
- Give IM doses into large muscle mass (rotate sites)
- Give IV doses over 30-60 minutes & flush IV tubing after
- Always observe for drug interactions
Antimicrobial Pt Education
- Take all prescribed doses; do not stop when symptoms subside
- Do not take meds left over form previous illness or prescribed to someone else
- Report all other drugs being taken
- Some antibiotics decrease effectiveness of estrogens & OCPs (–> Ampicillin, Nitrofurantoin, Penicillin V, Sulfonamides, Tetracyclines)
- Report all drug allergies
Overall Adverse Effects
- Hypersensitivity (anaphylaxis, serum sickness, acute interstitial nephritis)
- Superinfection
- N/V/diarrhea
- Nephrotoxicity
- Neurotoxicity (HA, dizziness, confusion, restlessness)
- Bleeding (platelet dysfunction)
Antibiotic Agents
- Beta Lactams (Penicillins, Cephalosporins)
- Tetracyclines
- Aminoglycosides
- Fluoroquinolones
- Macrolides
- Sulfonamides
Beta-Lactams
MOA: inhibition of bacterial cell wall synthesis
- USE: Gram - and + bacteria
- Penicillins: *respiratory, GI, & GU infxns
- Cephalosporins: *respiratory infxns, surgical prophylaxis, resistant microorganisms, *best for gram - bacteria
B-Lactams & Resistance
- The B-lactam ring is part of the core structure of several antibiotic families
- Some produce B-lactamases–enzymes capable of destroying penicillins & cephalosporins (resistance)
B-Lactamase Enzyme Inhibitors
- Clavulanic acid
- Tazobactum
- Sulbactam
Penicillin/B-Lactamase Enzyme Inhibitor Combinations
- Ampicillin/Sulbactam (Unasyn)
- Amoxicillin clavulanate (Augmentin)
- Piperacillin/Tazobactam (Zosyn)
Penicillins
- Natural Penicillins (narrow-spectrum)- (Penicillin G, Penicillin V)
- Penicillinase-resistant penicillins (narrow)-(Cloxacillin, Dicloxacillin, Methicillin, Nafcillin, Oxacillin)
- Aminopenicillins (broad-spectrum)-(Amoxicillin, Ampicillin, Bacampicillin)
- Extended-spectrum penicillins-(Piperacillim, Carbenicillin, Mezlocillin)
Penicillins: Narrow-Spectrum
- Penicillin G (B-lactamase sensitive)
- Parenterally
- Most potent penicillin
- Penicillin V (given for minor infxns)
- Orally
Covers–Strep pyogenes, S. pneumoniae, Neisseria meningitis, N. gonorrhoeae, treponemes, Listeria, Actinomycetes, Clostridia
Penicillins: Broad-Spectrum
Ampicillin or Amoxycillin
- B-lactamase sensitive
- PO or parenterally (amoxycyillin better PO)
- Less active than Penicillin G against Gram + bacteria
- Covers narrow spectrum + Klebsiella & Proteus strains
Cephalosporins
- Broad spectrum
- Divided into generations based on antimicrobial activity
- Structurally & pharmacologically similar to penicillins
Cephalosporins: 1st Generation
- Cephalexin (PO, Keflex)
- Cefazolin (IV/PO)
- Cephapirin
Cephalosporins: 2nd Generation
- Cefaclor (PO)
- Cefoxitin (IV/IM)
Cephalosporins: 3rd Generation
- Cefixime (PO)
- Ceftiaxone (IV/IM, Rocephin)
Cephalosporins: 4th Generation
- Cefepime (IV/IM)
B-Lactams Adverse Effects
Penicillins: Hypersensitivity/allergy, superinfections, N/V, diarrhea, AP
Cephalosporins: Nephrotoxicity, HA, dizziness, weakness, fever, bleeding
B-Lactams Contraindications
- Cross-sensitivity w/ Penicillin –> If allergic to Penicillin, do not take/cautiously take Cephalosporins
- Use may decrease effectiveness of OCPs by diminishing enterohepatic circulation
Penicillin: Pt Education
- Take w/ full glass of water on empty stomach
- Use different form of birth control while taking these
Cephalosporin: Pt Education
- Take w/ food if gastric upset occurs
- Do not consume alcohol while on these antibiotics
- Caution w/ taking ASA or NSAIDs or anticoagulants as bleeding tendencies intensify
Tetracycline
- MOA: penetrates microbial cells & binds to 30S ribosomes -> inhibit microbial protein synthesis (bacterostatic & bactericidal)
- *Broad spectrum
USE: Gram + and - organisms plus, rickettsia, mycoplasmas, some protozoa, spirochetes, & others
Tetracyclines: Indications
1st line therapy w/:
- Cholera, granuloma, inguinale, chancroid, RMSF, psittacosis, typhus, trachoma
Penicillin substitute if allergic for STDs, long term tx of acne, & prevention of traveler’s diarrhea
Tetracycline Drugs
- Tetracycline
- Demeclocycline
- Doxycycline
- Minocycline
Tetracycline: Pt Education
- Tetracyclines bind to Ca, Mg, & Al
- Do not take w/ dairy products, antacids, iron supplements, or magnesium laxatives -> reduce their absorption (within 2 hours)
Tetracycline: Adverse Effects
- Permanent stains in developing teeth of fetus & children
- Photosensitivity
- Superinfection
- Diarrhea, GI upset
Tetracycline: Contraindications
- Pregnancy (retards fetal skeletal development)
- Children up to 8 years of age
Aminoglycoside
- MOA: Penetrates cell walls of susceptible bacteria, binds irreversibly to 30S ribosomes, & inhibits protein synthesis (bactericidal)
- Narrow spectrum (VERY POTENT)
- USE: Gram - (aerobic) organisms
- Reserved for serious/life threatening infxns
- Ex: respiratory, resistant TB
Aminoglycoside Drugs
- Gentamicin
- Amikacin
- Neomycin
- Streptomycin
- Kenamycin
- Tobramycin
- POOR ORAL ABSORPTION*
Aminoglycoside: Adverse Effects/CI
AE: - Nephrotoxicity - N/V/diarrhea - Ototoxicity (auditory impairment) CI: - Renal disease (do not combine w/ loop diuretics) - MUST MONITOR DRUG LEVELS
Flouroquinolones
- Broad spectrum*
- MOA: (Bactericidal)-interfere w/ DNA gyrase-enzyme needed for bacterial synthesis
- USE: Gram - and + bacteria
- respiratory infections
Fluoroquinolone Drugs
- Ciprofloxacin*–(Cipro)
- Levofloxacin (Levaquin)
- Many more…
Excellent oral absorption-reduced w/ antacids
Fluoroquinolone: Adverse Effects/CI
AE:
- Allergy/rashes
- N/V/diarrhea
- HA, dizziness, drowsiness, restlessness
- Photosensitivity (ciprofloxacin)
CI:
- Children, infants, pregnant, or lactating
Fluoroquinolone: Drug Interactions
- Increases the effects of anticoagulants & caffeine
- DO NOT TAKE w/ antacids, milk, iron supplements, or magnesium laxatives
Macrolides
- Broad Spectrum*
- MOA: Attach to 50S ribosomes -> inhibit microbial protein synthesis (bacterostatic & bactericidal in large doses)
- USE: Gram +, some anaerobic & atypical mycobacterium
- respiratory tract infxns, penicillin substitute if allergic, prophylaxis for rheumatic fever, & STDs, tx of Legionnaire’s DZ
Macrolide Drugs
- Erythromycin
- Azithromycin (Zithromax)
- Clarithromycin
- Dirithromycin
Macrolide: Pt Education
- Effective on empty stomach, but may give w/ food if GI upset occurs
Macrolide: Adverse Effects/CI
AE: - N/V/diarrhea - Hepatoxicity - HA, dizziness - GI upset (erythromycin) CI: - Pre-existing liver disease
Sulfonamide
- MOA: (bacterostatic)-inhibits multiplication
- USE: wide range
- Primary use in UTI tx
Sulfonamide Drugs
- Single Agents: Sulfamethoxazole, Sulfisoxazole
- Combination Agents: Trimethoprim-Sulfamethoxazole (Bactrim, Septra)
- Topical Agents: Silver Sulfadiazine (Silvadene)–burns
Sulfonamide: Adverse Effects/CI
AE: - Kidney damage - Photosensitivity - GI upset CI: - Renal failure - Late pregnancy, lactation & children
Sulfonamide: Pt Education
- Take w/ water on empty stomach
- Drink 8-10 glasses of water to prevent crystallization of sulfa in the kidneys
- Wear protective clothing & sunscreen
- Urine should be acidic for sulfonamides to work
- Avoid carbonated beverages
Antimicrobials & Nursing
Before initiation, assess for –> drug allergies, hepatic liver & cardiac functions, potential drug interactions
*Must obtain cultures before initiation
After initiation –> watch for signs of superinfection (e.g. fever, cough, lethargy, perineal itching)
