, Antimicrobial Therapy & Antihelminthics Reviewer
Reference: Rosenthal & Burchum, 2026; CDC, 2024
o Five generations; increasing gram-
Chapter 72: Basic Principles of negative activity and beta-
lactamase resistance.
Antimicrobial Therapy
o 1st gen (cefazolin) → staph/strep.
• Selective Toxicity = ability of drug to
kill/inhibit microbes without harming o 3rd gen (ceftriaxone) →
host. meningitis, gonorrhea.
• Classification: o 5th gen (ceftaroline) → MRSA.
o By susceptible organism: • Carbapenems (imipenem): Ultra broad
antibacterial, antifungal, antiviral. spectrum, resistant to most beta-
o By MOA: inhibit cell wall lactamases.
synthesis, protein synthesis, nucleic • Vancomycin:
acids, etc. o Not a beta-lactam, but inhibits cell
• Bactericidal vs. Bacteriostatic: wall synthesis.
o Cidal → kills bacteria. o Used for MRSA, C. diff (oral).
o Static → slows growth, relies on o Risks: nephrotoxicity, ototoxicity,
host immunity. “red man syndrome.”
• Resistance:
o Microbe may ↓ drug uptake, ↑ drug Chapter 75: Bacteriostatic Inhibitors of
inactivation, alter drug target sites, Protein Synthesis
or pump drug out (efflux). • Tetracyclines (doxycycline): Broad
o Big issue: MRSA, VRE, spectrum, used for acne, atypicals
multidrug- resistant TB. (chlamydia, Lyme).
• Superinfection: o Risks: teeth discoloration (avoid <8
o New infection during treatment of yrs), photosensitivity, GI upset.
another. Example: C. difficile • Macrolides (azithromycin,
after broad-spectrum antibiotics. erythromycin):
• Prophylaxis: o Used for strep throat in PCN
o Given to prevent infection allergy, atypical pneumonia.
(e.g., before surgery, recurrent o Risks: QT prolongation, GI upset,
UTIs, CYP3A4 interactions.
immunocompromised pts). • Clindamycin:
o Effective for anaerobes.
Chapter 73: Penicillins (PCNs) o High risk of C. diff infection.
• MOA: Weaken bacterial cell wall → lysis.
• Bactericidal, time-dependent. Chapter 76: Aminoglycosides (Bactericidal
• Resistance: Beta-lactamase production,
altered PBPs (penicillin-binding proteins).
Protein Synthesis Inhibitors)
• Gentamicin, Amikacin, Tobramycin.
• Types:
• MOA: Cause misreading of mRNA →
o Narrow-spectrum PCN G, V
defective proteins → bacterial death.
(strep, syphilis).
• Uses: Serious gram-negative infections.
o Broad-spectrum aminopenicillins
• Risks: Ototoxicity, nephrotoxicity,
(amoxicillin, ampicillin). neuromuscular blockade.
o Antistaphylococcal • Monitor drug levels (narrow therapeutic
(nafcillin, oxacillin, index).
dicloxacillin).
o Antipseudomonal
(piperacillin/tazobactam). Chapter 77: Sulfonamides & Trimethoprim
• Allergy: Rashes → anaphylaxis. Cross- • MOA: Inhibit folic acid synthesis
reactivity with cephalosporins. (bacteria need to make their own).
Chapter 74: Other Cell Wall Drugs
• Cephalosporins:
Reference: Rosenthal & Burchum, 2026; CDC, 2024
o Five generations; increasing gram-
Chapter 72: Basic Principles of negative activity and beta-
lactamase resistance.
Antimicrobial Therapy
o 1st gen (cefazolin) → staph/strep.
• Selective Toxicity = ability of drug to
kill/inhibit microbes without harming o 3rd gen (ceftriaxone) →
host. meningitis, gonorrhea.
• Classification: o 5th gen (ceftaroline) → MRSA.
o By susceptible organism: • Carbapenems (imipenem): Ultra broad
antibacterial, antifungal, antiviral. spectrum, resistant to most beta-
o By MOA: inhibit cell wall lactamases.
synthesis, protein synthesis, nucleic • Vancomycin:
acids, etc. o Not a beta-lactam, but inhibits cell
• Bactericidal vs. Bacteriostatic: wall synthesis.
o Cidal → kills bacteria. o Used for MRSA, C. diff (oral).
o Static → slows growth, relies on o Risks: nephrotoxicity, ototoxicity,
host immunity. “red man syndrome.”
• Resistance:
o Microbe may ↓ drug uptake, ↑ drug Chapter 75: Bacteriostatic Inhibitors of
inactivation, alter drug target sites, Protein Synthesis
or pump drug out (efflux). • Tetracyclines (doxycycline): Broad
o Big issue: MRSA, VRE, spectrum, used for acne, atypicals
multidrug- resistant TB. (chlamydia, Lyme).
• Superinfection: o Risks: teeth discoloration (avoid <8
o New infection during treatment of yrs), photosensitivity, GI upset.
another. Example: C. difficile • Macrolides (azithromycin,
after broad-spectrum antibiotics. erythromycin):
• Prophylaxis: o Used for strep throat in PCN
o Given to prevent infection allergy, atypical pneumonia.
(e.g., before surgery, recurrent o Risks: QT prolongation, GI upset,
UTIs, CYP3A4 interactions.
immunocompromised pts). • Clindamycin:
o Effective for anaerobes.
Chapter 73: Penicillins (PCNs) o High risk of C. diff infection.
• MOA: Weaken bacterial cell wall → lysis.
• Bactericidal, time-dependent. Chapter 76: Aminoglycosides (Bactericidal
• Resistance: Beta-lactamase production,
altered PBPs (penicillin-binding proteins).
Protein Synthesis Inhibitors)
• Gentamicin, Amikacin, Tobramycin.
• Types:
• MOA: Cause misreading of mRNA →
o Narrow-spectrum PCN G, V
defective proteins → bacterial death.
(strep, syphilis).
• Uses: Serious gram-negative infections.
o Broad-spectrum aminopenicillins
• Risks: Ototoxicity, nephrotoxicity,
(amoxicillin, ampicillin). neuromuscular blockade.
o Antistaphylococcal • Monitor drug levels (narrow therapeutic
(nafcillin, oxacillin, index).
dicloxacillin).
o Antipseudomonal
(piperacillin/tazobactam). Chapter 77: Sulfonamides & Trimethoprim
• Allergy: Rashes → anaphylaxis. Cross- • MOA: Inhibit folic acid synthesis
reactivity with cephalosporins. (bacteria need to make their own).
Chapter 74: Other Cell Wall Drugs
• Cephalosporins:
