High-Yield Antibiotics & Antifungals – First Aid 2025 Summary (Video Notes)

A comprehensive set of Q&A flashcards covering MOA, uses, and adverse effects for major antibiotics and antifungals from the lecture notes.

What is the MOA of penicillins (Penicillin G, Penicillin V)?

Bind penicillin-binding proteins (PBPs) to block peptidoglycan cross-linking in the bacterial cell wall.

What are the primary uses of penicillins G and V?

Gram-positive cocci (Streptococcus), Actinomyces; some Gram-negative cocci; spirochetes (e.g., syphilis).

What are common adverse effects of penicillins?

Hypersensitivity reactions and hemolytic anemia.

What is the MOA of antistaphylococcal penicillins (nafcillin, oxacillin, dicloxacillin)?

Penicillinase-resistant; designed to treat penicillinase-producing Staphylococcus aureus (except MRSA).

What is the primary use of antistaphylococcal penicillins?

Staphylococcus aureus infections, excluding MRSA.

What are common adverse effects of antistaphylococcal penicillins?

Hypersensitivity and interstitial nephritis.

What is the MOA of aminopenicillins (amoxicillin, ampicillin)?

Penicillinase-sensitive agents; often combined with a β-lactamase inhibitor.

What organisms are targeted by aminopenicillins (HELPSS)?

H. influenzae, H. pylori, E. coli, Listeria, Proteus, Salmonella, Shigella.

What are common adverse effects of aminopenicillins?

Hypersensitivity, rash, pseudomembranous colitis.

What is the MOA of antipseudomonal penicillins (piperacillin, ticarcillin)?

Extended-spectrum penicillins with activity against Pseudomonas and Gram-negative rods; used with β-lactamase inhibitors.

What are the uses of antipseudomonal penicillins?

Pseudomonas infections and other Gram-negative rods; often combined with β-lactamase inhibitors.

What are common adverse effects of antipseudomonal penicillins?

Hypersensitivity reactions.

What is the MOA of β-lactamase inhibitors (clavulanic acid, sulbactam, tazobactam)?

Protect penicillins from β-lactamase enzymes; extend antibiotic spectrum when combined with penicillins.

What is the use of β-lactamase inhibitors?

Combined with penicillins to broaden coverage and prevent β-lactamase–mediated inactivation.

What is the general MOA of cephalosporins (generations I–V)?

β-lactam drugs that inhibit cell wall synthesis; less susceptible to some penicillinases.

What does first-generation cephalosporin coverage (PEcK) include?

Proteus, E. coli, Klebsiella.

What does second-generation cephalosporin coverage (HEN PEcKS) include?

Haemophilus influenzae, Enterobacter, Neisseria, Serratia; coverage expanded to more gram-negatives.

What are typical uses of third-generation cephalosporins (e.g., ceftriaxone, cefotaxime, ceftazidime)?

Serious Gram-negative infections; ceftriaxone for meningitis, gonorrhea, Lyme disease.

What are typical uses of fourth-generation cephalosporin (cefepime)?

Broad Gram-negative coverage including Pseudomonas; also active against some Gram-positive cocci.

What are typical uses of fifth-generation cephalosporin (ceftaroline)?

MRSA coverage (not Pseudomonas).

What are common adverse effects of cephalosporins?

Hypersensitivity, autoimmune hemolytic anemia, disulfiram-like reaction, vitamin K deficiency.

What is the MOA of carbapenems (imipenem, meropenem, ertapenem, doripenem)?

Broad-spectrum β-lactamase–resistant agents that inhibit cell wall synthesis.

What are the uses of carbapenems?

Severe, life-threatening infections; broad coverage including many resistant organisms.

What are common adverse effects of carbapenems?

GI upset, rash, seizures (especially with imipenem).

What is the MOA of monobactams (aztreonam)?

Less susceptible to β-lactamases; binds PBP3 to inhibit cell wall synthesis.

What are the uses of aztreonam?

Gram-negative rods; safe for penicillin-allergic patients or renal impairment.

What are common adverse effects of aztreonam?

Usually nontoxic.

What is the MOA of vancomycin?

Binds D-Ala-D-Ala termini to inhibit peptidoglycan polymerization (cell wall synthesis).

What are the uses of vancomycin?

Gram-positive organisms only (MRSA, Enterococcus, C. difficile (oral for infection in gut)).

What are common adverse effects of vancomycin?

Nephrotoxicity, ototoxicity, thrombophlebitis, Red man syndrome.

What is the MOA of aminoglycosides (gentamicin, amikacin, tobramycin, streptomycin)?

Inhibit 30S ribosomal subunit causing misreading of mRNA; bactericidal.

What are the uses of aminoglycosides?

Severe Gram-negative infections; synergistic with β-lactams for some infections.

What are common adverse effects of aminoglycosides?

Nephrotoxicity, ototoxicity, teratogenicity, neuromuscular blockade.

What is the MOA of tetracyclines (doxycycline, minocycline)?

Bind 30S and prevent attachment of aminoacyl-tRNA; bacteriostatic.

What are typical uses of tetracyclines?

Borrelia, Mycoplasma, Rickettsia, Chlamydia.

What are common adverse effects of tetracyclines?

Teeth discoloration, inhibition of bone growth, photosensitivity; contraindicated in pregnancy.

What is the MOA of chloramphenicol?

Inhibits 50S peptidyltransferase.

What are typical uses of chloramphenicol?

Meningitis, RMSF (alternative therapy due to toxicity).

What are common adverse effects of chloramphenicol?

Anemia, aplastic anemia, Gray baby syndrome.

What is the MOA of clindamycin?

Blocks 50S peptidyltransferase.

What are typical uses of clindamycin?

Anaerobic infections above the diaphragm (aspiration pneumonia, lung abscess).

What are common adverse effects of clindamycin?

Pseudomembranous colitis (C. difficile), fever, diarrhea.

What is the MOA of macrolides (azithromycin, clarithromycin, erythromycin)?

Block 50S ribosomal translocation.

What are typical uses of macrolides?

Atypical pneumonia (Mycoplasma, Chlamydia, Legionella), STIs, G+ cocci.

What are common adverse effects of macrolides?

GI motility issues, arrhythmias (QT prolongation), cholestatic hepatitis, rash, eosinophilia.

What is the MOA of linezolid?

Inhibits 50S initiation complex.

What are typical uses of linezolid?

Gram-positive resistant organisms (MRSA, VRE).

What are common adverse effects of linezolid?

Bone marrow suppression, serotonin syndrome, peripheral neuropathy.

What is the MOA of fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin)?

Inhibit DNA gyrase (topoisomerase II) and topoisomerase IV.

What are common uses of fluoroquinolones?

Gram-negative rods (UTI, GI infections); some Gram-positive; Pseudomonas.

What are common adverse effects of fluoroquinolones?

Tendon rupture, cartilage damage, QT prolongation; contraindicated in pregnancy and children.

What is the MOA of metronidazole?

Forms toxic free radicals causing DNA damage.

What are typical uses of metronidazole?

Giardia, Entamoeba, Trichomonas, Gardnerella, anaerobes (Bacteroides, C. difficile), H. pylori.

What are common adverse effects of metronidazole?

Disulfiram-like reaction with alcohol, headache, metallic taste.

What is the MOA of rifamycins (rifampin, rifabutin)?

Inhibit DNA-dependent RNA polymerase.

What are typical uses of rifamycins?

TB, leprosy; prophylaxis for meningococcus and H. influenzae; prophylaxis in some contexts.

What are common adverse effects of rifamycins?

Hepatotoxicity, orange body fluids, CYP450 induction (rifabutin less so).

What is the MOA of sulfonamides (sulfamethoxazole, sulfisoxazole, sulfadiazine)?

Inhibit dihydropteroate synthase, blocking folate synthesis.

What are typical uses of sulfonamides?

Gram-positive and Gram-negative bacteria; Nocardia; Chlamydia; often combined with TMP.

What are common adverse effects of sulfonamides?

Hypersensitivity, hemolysis in G6PD deficiency, nephrotoxicity, photosensitivity, kernicterus.

What is the MOA of trimethoprim?

Inhibits bacterial dihydrofolate reductase.

What are typical uses of trimethoprim?

UTIs, Shigella, Salmonella, Pneumocystis jirovecii.

What are common adverse effects of trimethoprim?

Megaloblastic anemia, leukopenia, granulocytopenia (co-administer folinic acid).

What is the MOA of dapsone?

Inhibits dihydropteroate synthase (folate synthesis) similar to sulfonamides.

What are typical uses of dapsone?

Leprosy; Pneumocystis jirovecii prophylaxis.

What are common adverse effects of dapsone?

Hemolysis in G6PD deficiency; methemoglobinemia.

What is the MOA of daptomycin?

Disrupts cell membrane integrity; forms pores.

What are typical uses of daptomycin?

MRSA, VRE; not for pneumonia.

What are common adverse effects of daptomycin?

Myopathy, rhabdomyolysis.

What is the MOA of polymyxins (polymyxin B, colistin)?

Cationic polypeptides that disrupt bacterial cell membranes to increase permeability.

What are typical uses of polymyxins?

Multidrug-resistant Gram-negative bacteria.

What are common adverse effects of polymyxins?

Nephrotoxicity, neurotoxicity, potential respiratory failure.

What is the MOA of amphotericin B?

Binds ergosterol, forms pores in fungal cell membranes.

What are typical uses of amphotericin B?

Systemic mycoses (Cryptococcus, Blastomyces, Coccidioides, Histoplasma, Candida, Mucor).

What are common adverse effects of amphotericin B?

Fever/chills, nephrotoxicity, hypotension, arrhythmias, anemia.

What is the MOA of nystatin?

Binds ergosterol like amphotericin B; forms membrane pores.

What are typical uses of nystatin?

Topical/oral candidiasis; not for systemic use.

What is the MOA of azoles (fluconazole, ketoconazole, itraconazole, voriconazole)?

Inhibit fungal CYP450 enzymes; block ergosterol synthesis.

What are typical uses of azoles?

Local and some systemic fungal infections; fluconazole for Cryptococcus and Candida.

What are common adverse effects of azoles?

Hepatotoxicity, CYP450 inhibition, possible testosterone synthesis inhibition (gynecomastia).

What is the MOA of echinocandins (caspofungin, micafungin, anidulafungin)?

Inhibit synthesis of β-glucan, a key component of the fungal cell wall.

What are typical uses of echinocandins?

Invasive aspergillosis and Candida infections.

What are common adverse effects of echinocandins?

GI upset, flushing (histamine release).

What is the MOA of flucytosine?

Converted to 5-FU; inhibits DNA and RNA synthesis.

What are typical uses of flucytosine?

Cryptococcus (in combination with amphotericin B).

What are common adverse effects of flucytosine?

Bone marrow suppression.

What is the MOA of griseofulvin?

Inhibits microtubule function, disrupting mitosis.

What are typical uses of griseofulvin?

Dermatophytes (tinea, ringworm).

What are common adverse effects of griseofulvin?

Teratogenic, carcinogenic potential; headache, confusion; CYP450 induction; disulfiram-like rxn.

What is the MOA of terbinafine?

Inhibits squalene epoxidase → decreased ergosterol synthesis.

What are typical uses of terbinafine?

Dermatophytoses and onychomycosis.

What are common adverse effects of terbinafine?

GI upset, hepatotoxicity, taste disturbance.