Penicillins, cephalosporins, vanomycin Mechanism of Action
inhibit bacterial cell wall synthesis/activation of enzymes that disrupt bacterial cell walls
Antifungals MOA
disruption of microbial ell membranes
Aminoglycosides, clindamycin, erythromycin, tetracyclines MOA
inhibition of protein synthesis by bacterial or porduction of abnormal bacterial proteins (bind irreversibly with bacterial ribosomes so cannot synthesize proteins)
Fluroquinolones, rifampin, antivirals MOA
inhibition of organism production by interfering with nucleic acid synthesis
sulfonamides, trimethoprim
inhibition of cell metabolism and growth
Beta-Lactams
Penicillin and Cephalosporins
MOA: inhibit bacterial cell wall synthesis
Used to treat infections caused by gram-positive and gram-negative bacteria
-Penicillins: respiratory infections, GI and genitourinary infections, best for gram positive
-Cephalosporins: respiratory infections, skin, soft tissue, bone, joint, UTI, surgical prophylaxis, infections caused by resistant microorganisms, best for gram-negative infections
AE:
- Penicillin: allergy, superinfections, N & V, diarrhea, abd pain
- Cephalosporins: nephrotox, HA, dizzy, weak, fever, bleeding
Contraindications - both -
- cross sensitivity betwn the two because chemically similar, if allergic to pens cautions w/ cephs
- use may decrease effectiveness of BC by diminishing enterophepatic circulation
Penicillin G
- parenterally
- most potent penicillin
- narrow spectrum: strepptococcus pyogenes, S. pneumoniae, Neisseria Meningitis, N. gonorrhoeae, treponemes, listeria, actinomycetes, clostridia
- Beta lactamase sensitive
Ampicillin
Beta lactamase sensitive
- orally or parenterally
- less active than penicillin G against gram positive bacteria
- Wide spectrum: strep pyogenes, S. pneumoniae, Neisseria Meningitis, N. gonorrhoeae, treponemes, listeria, actinomycetes, clostridia AND klebsiella and proteus strains
Amoxycillin: the same as ampicillin except it is better absorbed orally
Cephalosporins: broad spectrum
1st Gen: -cephalexin(PO, keflex) -Cefazolin (IV/PO, Kefzol, Ancef) 2nd Gen: -Cefaclor (PO, Ceclor) -Cefoxitin (IV/IM, Mefoxin) 3rd Gen: -cefixime (PO, suprax) -ceftiaxone (IV/IM, rocephin) 4th Gen: -cefepime (IV/IM, maxipime) Similar to penicillins
Tetracyclines: broad spectrum
MOA-penetrates microbial cells by passive diffusion/active transport system and binds to ribosomes and inhibit microbial protein synthesis
Use-infections caused by wide range of gram positive and negative organisms and rickettsia, mycoplasmas, protozoa, spirochetes
- drug of choice for: cholera, granuloma, infuinale, chancroid, rocky mtn spotted fever, chlamydia, STD infections, long term acne tx and prevention of travelers diarrhea
- pen sub if allergic
tetracycline (achromycin)
demeclocycline (declomycin)
doxycycline (vibramycin)
-bacteriostatic and bactericidal
-Do not take with dairy products, antacids, iron, or magnesium laxatives - reduce absorption
AE: permanent stains in developing teeth in fetus and children, photosensitivity, superinfections, diarrhea, GI upset
Contraindications: pregnancy, children 8 y and younger
Aminoglycosides
MOA: penetrates cell walls of susceptible bacteria and binds irreversibly to ribosomes and intracellular structures that synthesize proteins necessary for function and replication (bactericidal)
- Uses: gram negative organisms, serious life threatening infections, systemic aerobic gram negative infections in respiratory and GI tracts, skin, wounds, bowel, bloodstream, resistant TB, suppress GI flora, may be used w/ cephs and vancomycin for synergistic effects
- Poor oral absorption
Gentamicin (garamycin) Amikacin Neomycin Streptomycin Kanamycin Tobramycin
AE: nephrotox, N & V, diarrhea, auditory impairment, peripheral neuritis, tingling/numb, HA, dizzy, fever
Contraindications: renal impairment, do not combine w/ loop diuretics
Flouroquinolones: broad spectrum
MOA: interfering with DNA gyrase, an enzyme required for synthesis of bacterial DNA and therefore required for bacterial growth and replication (Bactericidal)
-Used for gram-negative and positive organisms: respiratory infections, GI, bone, skin, joints, soft tissue, gonorrhea, multidrug resistant TB
Ciprofloxacin (Cipro) Enoxacin (Penetrex) Levofloxacin (Levaquin) Norfloxacin (Noroxin) Ofloxacin (Floxin)
-good oral absorption (reduced by antacids)
-1st oral abx effective against gram neg
AE: allergy rxn/rashes,N & V, diarrhea, HA, dizzy, drowsy, fatigue, restless, photosens
Contraindications: children/infants, preg/lactating
Interactions: cipro increases effects of anticoags and caffeine - not be taken w/ antacids, milk, iron, magnesium laxatives
Macrolides
MOA: enter microbial cells and attach to ribosomes thereby inhibiting microbial protein synthesis (bacteriostatic and bacteriacidal in large doses)
-Used to treat gram-positive, some anaerobic organisms, atypical mycobaterium: respiratory infections, skin, prophylaxis for rheumatic fever, gonorrhea, syphilis, chlamydia, pen sub if allergic
Erythromcin
Axithromycin (Zithromax)
Clarithromycin (Biaxin)
Dirithromycin (Dynabac)
AE: hepatotox, N & V, diarrhea, HA, dizzy, GI upset on empty stomach
Contra: preexisiting liver disease
Sulfonamide
MOA: inhibits the multiplication of new bacteria (bacteriostatic)
-Used for wide range of infections: UTI’s, ulcerative colitis, topical for burn and ocular, vaginal and other soft tissue infections
Single agents
- sulfamethoxazole (gantanol)
- sulfisoxazole (gantrisin, for UTIs)
Combo agent
-Trimethoprim-sulfamethoxazole (Bactrim, Septra for UTIs)
Topical
-silver sulfadiazine (silvadene, burns)
AE: kidney damage, photosens, N & V, diarrhea, GI upset
-Take with full glass of water on empty stomach, drink 8-10 glass of water to prevent crystallization of sulfa in kidneys, wear protective clothing and sunscree, avoid carbonated beverages because urine should be acidic for it to work
Contra: renal failure, late preg, lactation, children
