Class Function Spectrum Diseases Special Citations

Penicillins Derived from Penicillium fungi All penicillins are β-lactam antibiotics Oldest known antibiotic

Subtypes

Natural Penicillins Penicillinase-resistant Penicillins

Methicillin, Oxacillin Aminopenicillin – extended spectrum, wider

coverageAmpicillin, Amoxicillin

Disrupt the synthesis of the peptidoglycan layer of bacterial cell walls

Narrow-spectrum

β-lactamase sensitive -Benzathine penicillin-Benzylpenicillin (penicillin G)-Phenoxymethylpenicillin (penicillin V)-Procaine penicillin

Penicillinase-resistant penicillins -Methicillin-Oxacillin-Nafcillin-Cloxacillin-Dicloxacillin-Flucloxacillin

β-lactamase-resistant penicillins -Temocillin

Moderate-spectrum-Amoxicillin-Ampicillin

Broad-spectrumCo-amoxiclav (amoxicillin+clavulanic acid)

Extended-spectrum-Azlocillin-Carbenicillin-Ticarcillin-Mezlocillin-Piperacillin

Wide range of infections; penicillin used for streptococcal infections, syphilis, and Lyme disease

Side effects

Gastrointestinal upset and diarrhea

Allergy with serious anaphylactic reactions

Brain and kidney damage (rare)

Pregnancy Category B

Cephalosphorins Beta-lactam ring structure (similar to Penicillins) Derived from cephalosporin C which is produced from

Cephalosporium acremonium Widely used for surgical prophylaxis Grouped into generations

First Generation Most gram positive, few gram negative Cefazolin, Cephalexin,, Cephapirin

Second Generation Gram positive, expanded gram negative

spectrum Cefaclor, Cefuroxime, Cefonicid

Third Generation Expanded gram negative spectrum, less

gram positive Cefixime, Ceftriaxone, Cefotaxime

Fourth Generation Extended coverage on both spectrums,

can cross BBB Greater resistance to beta lactamases

than 3rd generations Cefepime,Cefpirome, Cefclidine

Disrupt the synthesis of the peptidoglycan layer of bacterial cell walls

Good coverage against Gram positive infections

Less gram positive cover, improved gram negative cover

Improved coverage of Gram negative organisms, except Pseudomonas. Reduced Gram positive cover

Covers pseudomonal infections, extended coverage on both spectrums, can cross BBB, greater resistance to beat lactamases than 3rd generation

Treatment of bacterial infections caused by susceptible organisms

Surgical prophylaxis

(1st Generation)Skin & Soft Tissue Infections (SSTI)Upper Respiratory Tract Infections

(2nd Generation)Community Acquired PneumoniaBronchitis, Sinusitis, OtitisSkin & Soft Tissue Infections (SSTI)MSSAAbdominal Surgical Prophylaxis

(3rd Generation)Community acquired pneumoniaBacterial meningitis (except Listeria)Lyme disease Viridans strep endocarditisIntra-Abdominal & Pelvic InfectionsHospital Acquired PneumoniaAnogenital gonorrhea

5–10% of patients with hypersensitivity to penicillins will have cross-reactivity with cephalosporins

Side effects

Gastrointestinal upset and diarrhea

Nausea (if alcohol taken concurrently)

Allergic reactions

Pregnancy Category B

Flouroquinolones Contains the root “floxacin”

Ciprofloxacin, Ofloxacin, Levofloxacin, Norfloxacin

Inhibit the bacterial DNA gyrase or the topoisomerase IV enzyme, thereby inhibiting DNA replication and transcription

Broad Spectrum Urinary tract infections, bacterial prostatitis, community-acquired pneumonia, bacterial diarrhea, mycoplasmal infections, gonorrhea

Side effects Nausea (rare),

irreversible damage to central nervous system (uncommon), tendinosis (rare)

Pregnancy Category C

Tetracyclines Four rings in chemical structure Derived from a species of Streptomyces bacteria Malaria prophylaxis Tetracycline, Doxycycline, Minocycline

Inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex. They do so mainly by binding to the 30S ribosomal subunit in the mRNA translation complex

Broad Spectrum Acne treatment, Syphilis, chlamydial infections, Lyme disease, mycoplasmal infections, acne rickettsial infections

Side effects

Gastrointestinal upset

Sensitivity to sunlight

Potential toxicity to mother and fetus during pregnancy

Enamel hypoplasia (staining of teeth; potentially permanent)

transient depression of bone growth

Pregnancy Category D

Macrolides Derived from Streptomyces bacteria Have a macrocyclic lactone chemical structure Erythromycin – prototype of this class Clarithromycin, Azithromycin, Roxithromycin

Inhibition of bacterial protein biosynthesis by binding reversibly to the subunit 50S of the bacterial ribosome, thereby inhibiting translocation of peptidyl tRNA

Broad Spectrum

Active against gram-positive cocci (mainly staphylococci and streptococci) and bacilli, and to lesser-extent gram-negative cocci

Streptococcal infections, syphilis, upper respiratory tract infections, lower respiratory tract infections, mycoplasmal infections, Lyme disease

Nausea, vomiting, and diarrhea (especially at higher doses)

Prolonged QT interval (especially erythromycin)

Jaundice (used with caution in patients with liver dysfunction

Pregnancy Category C

Aminoglycosides Derived from various species of Streptomyces used along with penicillins or cephalosporins Amikacin, Gentamicin, Kanamycin, Neomycin,

Streptomycin, Tobramycin

Binding to the bacterial 30S ribosomal subunit (some work by binding to the 50S subunit), inhibiting the translocation of the peptidyl-tRNA from the A-site to the P-site and also causing misreading of mRNA, leaving the bacterium unable to synthesize proteins vital to its growth

Broad Spectrum

Infections caused by Gram-negative bacteria, such as Escherichia coli and Klebsiella particularly Pseudomonas aeruginosa. Effective against Aerobic bacteria (not obligate/facultative anaerobes) and tularemia

The major side effect is ototoxicity.

Streptomycin and Gentamicin are vestibulotoxic,

Amikacin, Neomycin, Dihydrostreptomycin, and Kanamicin are cochleotoxic

Pregnancy Category D