Unit 2 Flashcards
Antimicrobial drugs that inhibit cell wall synthesis
Penicillin, Cephalosporins, Carbapenems
Antimicrobial drugs that inhibit protein synthesis
Aminoglycosides, Tetracyclines, Chloramphenicol, Macrolides
Antimicrobial drugs that inhibit folic acid biosynthesis
Sulfonamides and Trimethoprim
Antimicrobial drugs that inhibit DNA/RNA synthesis
Fluoroquinolones
Antimicrobial drugs that inhibit membrane function
Amphotericin B
What are narrow-spectrum antibiotics and give an example
Chemo agents acting only on a single or limited group of microorganisms.
Ex: Isoniazid
What are extended-spectrum antibiotics and give an example
Antibiotics that are modified to be effective against gram + organisms and gram - organisms.
Ex: Ampicillin
What are broad-sprectrum antibiotics and give an example
Drugs that affect a wide variety of microbial species.
Ex: Tetracycline
Penicillin: Inhibitor of cell wall synthesis
Interferes with the last step of bacterial cell wall synthesis which is the cross-linking of adjancet peptidoglycan strands by a process known as transpeptidation;
Results in formation of weakened cell wall and ultimately cell death;
Regarded as bactericidal and work in a time-dependent fashion;
Therapeutic uses: Pneumococcal infections, Gonorrhea, and Syphillis
Beta-lactam antibiotics is determined by the stability of the drug to gastric acid and the severity of the infeciton, Some beta-lactams must be administered by IV or IM while others can be given orally;
Destroyed by the stomach acid;
AE’s: Hypersensitivity, Diarrhea, Nephritis, Neurotoxicity, Hematologic toxicity
Cephalosporins: Inhibitors of Cell Wall Synthesis
Closely related structurally and functionally to penicillin;
Have same mode of action;
Tend to be more resistant than beta-lactamases;
Classified as 1st, 2nd, 3rd, 4th, and advanced generations based on their bacterial susceptibility patterns and resistance to beta-lactamases;
Mainly administered IV or IM due to poor oral absorption, Few can penetrate CSF;
Elimination is via the tubular secretion/glomerular filtration; Ceftriaxone is excreted through the bile
AE’s: Stevens-Johnson Syndrome;
Should be watched when people who take it are allergic to penicillin
Carbapenems: Inhibitors of Cell Wall Synthesis
Synthetic Beta-lactam antibiotics that differ in structure from penicillin in that the sulfur atom of thiazolidine ring has been externalized and replaced by a C atom; Imipenem resists hydrolysis by most beta-lactamases;
Administered by IV and penetrates the CSF;
AE’s: Nausea, vomiting, and diarrhea
Protein Synthesis Inhibitors
Target bacterial ribosomes and inhibit bacterial protein synthesis;
Most agents exhibit bacteriostatic activity;
Bacterial ribosomes differ structurally from mammalian cytoplasmic ribosomes and are composed of 30S and 50S
Tetracyclines, Glycycylines, Aminoglycosides, Macrolides/Ketolides, Macrocyclic, Lincosamides, Oxazolidinones, and others
Tetracyclines: Protein Synthesis Inhibitor
MOA: Enter organism via passive diffusion & by energy-dependent transport protein mechanism unique to the bacterial inner cytoplasmic membrane. Drug binds reversibly to the 30S subunit of bacterial ribosome and prevents binding of tRNA to the mRNA-ribosome complex, thereby inhibiting bacterial protein synthesis;
Bacteriostatic antibiotics effective against a wide variety of organisms: gram +, gram -, protozoa, spirochetes, and mycobacteria;
Resistance due to an efflux pump within bacteria that expels the drug, prevent intracellular accumulation
Uses: Peptic ulcer disease, Lyme disease, Mycoplasma pneumoniae, Cholera, Chlamydia, and Rocky mountain spotted fever;
Adequately absorbed after oral ingestion, some forms delivered IV/IM. Oral with dairy products - decreased absorption due to formation of non-absorbable chelates;
Concentrates in liver, bile, kidney, gingival fluid, and Skin. Binds to tissues undergoing calcification
Eliminated via unchanged urine
AE’s: Gastric discomfort, effects on calcified tissues, hepatotoxicity, phototoxicity, vestibular dysfunction, and contraindications
Aminoglycosides: Protein Synthesis Inhibitor
Used to treat serious infections due to aerobic gram - bacilli. Clinically limited due to serious toxicities;
Diffuse through porin channel and binds to 30S ribosomal subunit to interfere with assembly of functional ribosomal apparatus causing misread genetic code;
Used to treat Aerobic gram - bacilli, including those that are thought to be multidrug resistant;
Resistance via efflux pumps, decreased uptake, or modification and inactivation by plasmid-associated synthesis of enzymes;
Drug is highly polar preventing adequate oral absorption, administered topically for skin infections;
Concentrates in most body fluids, doesn’t enter CNS, crosses the placental barrier and may accumulate in fetal plasma and amniotic fluid;
Mainly excreted unchanged in urine
AE’s: Ototoxicity, Nephrotoxicity, Neuromuscular paralysis, and allergic reactions
Macrolides: Protein Synthesis Inhibitor
Group of antibiotics with a macrolytic lactone structure to which one or more deoxy sugars are attached. Erythromycin was the first drug to have clinical application and is used as an alternative to penicillin (when PT is allergic);
Bind irreversibly to a site on 50S subunit of bacterial ribosome, inhibiting translocation. Interferes with protein synthesis and transpeptidation;
Are bacteriostatic and bactericidal at high levels
Effective against many of the same organisms as penicillin;
Resistance through organism’s inability to take up macrolide, presence of efflux pumps, and decreased affinity of the 50S ribosomal subunit for the drug, and presence of plasmid associated esterase
Uses: Corynebacterium diphtheriae, Chlamydial infections, Legionnaire’s disease, Mycoplasma Pneunomia, Mycobacterium avium complex
Erythromycin (E) is destroyed by gastric acid where Clarithromycin (C) and Azithromycin (A) are stable in stomach acids and readily absorbed;
E goes to all body fluids except the CSF. C & A widely distribute to all tissues. A concentrates in neutrophils, macrophages, and fibroblasts;
E, A, C undergo hepatic metabolism and are excreted in bile
AE’s: Gastric distress, Cholestatic jaundice, Ototoxicity, QT prolongation, and contraindications
